Debris flows

Alluvial fans were studied in the field, largely in the desert regions of California, and in the laboratory. Field study consisted of detailed mapping of parts of four fans and reconnaissance work on over one hundred additional fans. Features mapped included the nature and age of deposits, material size, and channel pattern. In the laboratory small alluvial fans were built of mud and sand transported through a channel into a 5-foot by 5-foot box under controlled conditions. Material is transported to fans by debris flows or water flows that follow a main channel. This channel is generally incised at the fanhead, because there water is able to transport on a lower slope the material deposited earlier by debris flows. The main channel emerges onto the surface near a midfan point, herein called the "intersection point." On laboratory fans most deposition above the intersection point is by debris flows that exceed the depth of the incised channel. Fluvial deposition dominates below the intersection point. This depositional relation probably also occurs on natural fans. On fans deficient in fine material large discharges may infiltrate completely before reaching the toe of the fan. Coarse debris is then deposited as lobate masses, herein called "sieve deposits." In many respects sieve deposits resemble debris-flow deposits, but they lack primary fine material, and fresh lobes are highly permeable.

@article{doi101086627271,
    author = "Hooke, Roger LeB.",
    title = "Processes on Arid-Region Alluvial Fans",
    year = "1967",
    journal = "The Journal of Geology",
    abstract = {Alluvial fans were studied in the field, largely in the desert regions of California, and in the laboratory. Field study consisted of detailed mapping of parts of four fans and reconnaissance work on over one hundred additional fans. Features mapped included the nature and age of deposits, material size, and channel pattern. In the laboratory small alluvial fans were built of mud and sand transported through a channel into a 5-foot by 5-foot box under controlled conditions. Material is transported to fans by debris flows or water flows that follow a main channel. This channel is generally incised at the fanhead, because there water is able to transport on a lower slope the material deposited earlier by debris flows. The main channel emerges onto the surface near a midfan point, herein called the "intersection point." On laboratory fans most deposition above the intersection point is by debris flows that exceed the depth of the incised channel. Fluvial deposition dominates below the intersection point. This depositional relation probably also occurs on natural fans. On fans deficient in fine material large discharges may infiltrate completely before reaching the toe of the fan. Coarse debris is then deposited as lobate masses, herein called "sieve deposits." In many respects sieve deposits resemble debris-flow deposits, but they lack primary fine material, and fresh lobes are highly permeable.},
    url = "https://doi.org/10.1086/627271",
    doi = "10.1086/627271",
    openalex = "W2036897912",
    references = "doi1010160022169465901010, doi101061jyceaj0000852, doi101086621596, doi101086621915, doi101086623509, doi101098rspa19540186, doi101111j146783061963tb00464x, doi10113000167606195364547moawsc20co2, doi101680ipeds195511843, doi102307213147"
}

ABSTRACT The growth pattern of a deep-sea fan relates events in and around the fan-valleys to the structure and morphology of the open fan. The growth pattern cannot be determined without knowledge of the origin and recent history of the fan-valley system. The mapping of La Jolla and San Lucas deep-sea fans with the deep-towed instrument package developed at Marine Physical Laboratory of the Scripps Institution of Oceanography details the fine-scale morphology, structure, and internal fill of the fan-valleys and suggests the growth patterns of these fans. The La Jolla fan, 20 km west of Scripps Institution, has one meandering fan-valley that extends across the entire fan. Except on the toe of the fan, the deeply incised valley has terraced walls with steeper walls on the outside of meanders. Very low-relief levees border the fan-valley in some localities. The present erosional valley bypasses the partly buried remnants of an older distributary system on the lower fan. The San Lucas fan, off the southern tip of the peninsula of Baja California, shows a depositional lobe of sediment, or suprafan, below the short, leveed fan-valley extending from San Jose Canyon. The suprafan appears as a convex-upward bulge on a radial profile of the fan. The surface of the suprafan has a series of discontinuous depressions up to 55 m deep and 1 km wide. The depressions are generally asymmetric in cross section, commonly have terraced walls, and are underlain by coarse sand and gravel. They are interpreted to be channel remnants. A model for deep-sea fan growth, based on this study, predicts that deposition on a fan will be localized in a suprafan at the end of large, leveed valleys commonly found on, and generally confined to, the upper reaches of deep-sea fans. The suprafan normally is on the midfan and is characterized by numerous smaller distributary channels. Rapid aggradation in the suprafan coupled with migration and meandering of the channels produces a surface marked by isolated depressions or channel remnants. Uniform deposition, producing a symmetrical half-cone morphology, results from the shifting through time of fan-valleys across the area of the fan.

@article{doi1013065d25cc7916c111d78645000102c1865d,
    author = "Normark, William R.",
    title = "Growth Patterns of Deep-Sea Fans",
    year = "1970",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT The growth pattern of a deep-sea fan relates events in and around the fan-valleys to the structure and morphology of the open fan. The growth pattern cannot be determined without knowledge of the origin and recent history of the fan-valley system. The mapping of La Jolla and San Lucas deep-sea fans with the deep-towed instrument package developed at Marine Physical Laboratory of the Scripps Institution of Oceanography details the fine-scale morphology, structure, and internal fill of the fan-valleys and suggests the growth patterns of these fans. The La Jolla fan, 20 km west of Scripps Institution, has one meandering fan-valley that extends across the entire fan. Except on the toe of the fan, the deeply incised valley has terraced walls with steeper walls on the outside of meanders. Very low-relief levees border the fan-valley in some localities. The present erosional valley bypasses the partly buried remnants of an older distributary system on the lower fan. The San Lucas fan, off the southern tip of the peninsula of Baja California, shows a depositional lobe of sediment, or suprafan, below the short, leveed fan-valley extending from San Jose Canyon. The suprafan appears as a convex-upward bulge on a radial profile of the fan. The surface of the suprafan has a series of discontinuous depressions up to 55 m deep and 1 km wide. The depressions are generally asymmetric in cross section, commonly have terraced walls, and are underlain by coarse sand and gravel. They are interpreted to be channel remnants. A model for deep-sea fan growth, based on this study, predicts that deposition on a fan will be localized in a suprafan at the end of large, leveed valleys commonly found on, and generally confined to, the upper reaches of deep-sea fans. The suprafan normally is on the midfan and is characterized by numerous smaller distributary channels. Rapid aggradation in the suprafan coupled with migration and meandering of the channels produces a surface marked by isolated depressions or channel remnants. Uniform deposition, producing a symmetrical half-cone morphology, results from the shifting through time of fan-valleys across the area of the fan.",
    url = "https://doi.org/10.1306/5d25cc79-16c1-11d7-8645000102c1865d",
    doi = "10.1306/5d25cc79-16c1-11d7-8645000102c1865d",
    openalex = "W1979345769",
    references = "doi101086621596, doi101086623509, doi101086625999, doi101086627271, doi101126science1523721502, doi101130001676061969801859dfpap20co2, doi1013065ceae13616bb11d78645000102c1865d, doi1013065d25c61516c111d78645000102c1865d, doi101306bc743d7f16be11d78645000102c1865d, openalexw580680426"
}

ABSTRACT Turbidity currents may be generated in the oceans as part of the sequence from landsliding through debris flow to turbidity current flow. Three aspects of this sequence examined here are 1) the transition from landsliding to debris flow, 2) the mechanics of subaqueous debris flow, and 3) the transition from subaqueous debris flow to turbidity-current flow. The transition from landsliding to debris flow, as observed in the subaerial environment, occurs readily if water is incorporated into the landslide debris as it is jostled and remoulded during downslope movement. Remoulding and incorporation of water reduce the strength and increase the fluid behavior of the debris, thereby causing it to flow rather than slide. Incorporation of only a few percent water typically decreases the strength of landslide debris by a factor of two or more; therefore, landslide debris commonly becomes very fluid with incorporation of a small amount of water. The ready availability of water in the marine environment suggests that conditions are favorable for the development of subaqueous debris flows from subaqueous landslides. Debris flow has been modeled as flow of a plastico-viscous substance, which has a yield strength and deforms viscously at stresses greater than the yield strength. The conditions required for movement of a subaqueous debris flow are described in terms of a critical thickness of debris, which varies directly with strength and inversely with submerged trait weight and slope angle. Within a debris flow, viscous shear occurs where shear stress exceeds the shear strength of the debris, but where shear stress is less than shear strength the material is rafted along as a nondeforming plug. Distinct zones of viscous shear and nondeformation exist in a subaqueous debris flow. Transition from subaqueous debris flow to turbidity-current flow involves extensive dilution of debris-flow material, reducing the density from about 2.0 gm/cm3 to about 1.1 gm/cm3. In experiments, subaqueous debris-flow material was mixed with the surrounding water by erosion of material from the front of the flow and ejection of the material into the overlying water to form a dilute turbulent cloud (turbidity current). The amount of mixing, and hence the size of the turbidity current, varied inversely with the strength of the debris. Conditions that cause mixing at the front of a subaqueous debris flow are illustrated by analyzing flow around a half-body, with boundary-layer separation. Turbidity, currents also may be generated from subaqueous debris flows by mixing water directly into the body of the flow, behind the front, although this type of mixing was not observed in experiments. Mixing into the body of the flow can result from flow instability, either by breaking interface waves or by momentum transfer associated with turbulence, but available information suggests that mixing due to instability is inhibited by the presence of clay and coarse granular solids in debris. Mixing by erosion from the front of a debris flow is favored as being a more typical process of generating turbidity currents because this mixing is a natural consequence of debris flowing through water; it requires no special conditions to operate.

@article{doi10130674d7262b2b2111d78648000102c1865d,
    author = "Hampton, Monty A.",
    title = "The Role of Subaqueous Debris Flow in Generating Turbidity Currents",
    year = "1972",
    journal = "Journal of Sedimentary Research",
    abstract = "ABSTRACT Turbidity currents may be generated in the oceans as part of the sequence from landsliding through debris flow to turbidity current flow. Three aspects of this sequence examined here are 1) the transition from landsliding to debris flow, 2) the mechanics of subaqueous debris flow, and 3) the transition from subaqueous debris flow to turbidity-current flow. The transition from landsliding to debris flow, as observed in the subaerial environment, occurs readily if water is incorporated into the landslide debris as it is jostled and remoulded during downslope movement. Remoulding and incorporation of water reduce the strength and increase the fluid behavior of the debris, thereby causing it to flow rather than slide. Incorporation of only a few percent water typically decreases the strength of landslide debris by a factor of two or more; therefore, landslide debris commonly becomes very fluid with incorporation of a small amount of water. The ready availability of water in the marine environment suggests that conditions are favorable for the development of subaqueous debris flows from subaqueous landslides. Debris flow has been modeled as flow of a plastico-viscous substance, which has a yield strength and deforms viscously at stresses greater than the yield strength. The conditions required for movement of a subaqueous debris flow are described in terms of a critical thickness of debris, which varies directly with strength and inversely with submerged trait weight and slope angle. Within a debris flow, viscous shear occurs where shear stress exceeds the shear strength of the debris, but where shear stress is less than shear strength the material is rafted along as a nondeforming plug. Distinct zones of viscous shear and nondeformation exist in a subaqueous debris flow. Transition from subaqueous debris flow to turbidity-current flow involves extensive dilution of debris-flow material, reducing the density from about 2.0 gm/cm3 to about 1.1 gm/cm3. In experiments, subaqueous debris-flow material was mixed with the surrounding water by erosion of material from the front of the flow and ejection of the material into the overlying water to form a dilute turbulent cloud (turbidity current). The amount of mixing, and hence the size of the turbidity current, varied inversely with the strength of the debris. Conditions that cause mixing at the front of a subaqueous debris flow are illustrated by analyzing flow around a half-body, with boundary-layer separation. Turbidity, currents also may be generated from subaqueous debris flows by mixing water directly into the body of the flow, behind the front, although this type of mixing was not observed in experiments. Mixing into the body of the flow can result from flow instability, either by breaking interface waves or by momentum transfer associated with turbulence, but available information suggests that mixing due to instability is inhibited by the presence of clay and coarse granular solids in debris. Mixing by erosion from the front of a debris flow is favored as being a more typical process of generating turbidity currents because this mixing is a natural consequence of debris flowing through water; it requires no special conditions to operate.",
    url = "https://doi.org/10.1306/74d7262b-2b21-11d7-8648000102c1865d",
    doi = "10.1306/74d7262b-2b21-11d7-8648000102c1865d",
    openalex = "W2134038787"
}

@book{fisher1972clastic2,
    author = "Fisher, W. L. and Brown, L. F. and Jr",
    title = "Clastic depositional systems - a genetic approach to facies analysis",
    year = "1972",
    publisher = "Bureau of Economic Geology: University of Texas at Austin, p. 161-183",
    note = "talkorigins\_source = {true}; raw\_reference = {Fisher, W. L., and Brown, L. F., Jr., 1972, Clastic depositional systems - a genetic approach to facies analysis: Bureau of Economic Geology: University of Texas at Austin, p. 161-183.}"
}

@book{walker1973moppingup6,
    author = "Walker, R. G",
    title = "Mopping-up the turbidite mess, in Ginsburg, R. N., ed., Evolving Concepts in Sedimentology",
    year = "1973",
    publisher = "Baltimore, John Hopkins Press, p. 1-37",
    note = "talkorigins\_source = {true}; raw\_reference = {Walker, R. G., 1973, Mopping-up the turbidite mess, in Ginsburg, R. N., ed., Evolving Concepts in Sedimentology: Baltimore, John Hopkins Press, p. 1-37.}"
}

@misc{nelson1974depositional4,
    author = "Nelson, C. H. and Nilsen, T. H",
    title = "Depositional trends of modern and ancient deep-sea fans, in Modern and Ancient Geosynclinal Sedimentation",
    year = "1974",
    howpublished = "SEPM Special Publication 19, p. 69-91",
    note = "talkorigins\_source = {true}; raw\_reference = {Nelson, C. H., and Nilsen, T. H., 1974, Depositional trends of modern and ancient deep-sea fans, in Modern and Ancient Geosynclinal Sedimentation: SEPM Special Publication 19, p. 69-91.}"
}

ABSTRACT Apart from Bouma sequences, recurrent patterns of sedimentation can be recognized at two hierarchic levels in turbidite formations of the northern Apennines. First order cycles (turbidite suites) encompass most of the basin fill, second order cycles (megasequences) occur as organized groups of beds 2-70 m thick within the suites. The Marnoso-arenacea (Lower-Upper Miocene) is an example of a progradational or offlapping suite with thickening and coarsening upward trend. The Laga Formation (Upper Miocene-Lower Pliocene) is characterized by a transgressive (retrogradational) or onlapping trend. Vertical facies changes go either way through the following steps: basin plain outer fan midfan inner fan slope deposits (= prograding, = receding). Both suites are enclosed by hemipelagic pelites and chaotic deposits, the start of turbidite sedimentation being gradual in the progradational case, and abrupt (large scale erosion) in the reverse one. Second order cycles follow each other or are separated by monotonous (uniform or irregularly bedded) sequences of extremely variable thickness (2 to more than 1,000 m) composed either of fan (overbank, fringe) or basin plain deposits (with key beds laterally continuous up to 175 km). The trend of cycles may be asymmetric (termed positive when beds thin upward, negative when they thicken upward), symmetric, composite or not definable. Thick to massive beds with sand/shale ratio >> 1 or > 1 and well developed coarse divisions (products of high density turbidity currents, grain flows, debris flows, fluidized flows) form the thicker bedded portion of cycles and sometimes the whole cycle. One hundred and thirty-two cycles were analyzed and subdivided into simple and complex (= multiple or composite). By splitting multiple cycles into simple components, a total of 170 cycles was reached. Thirty-nine of them were measured in channelized deposits, 131 in non-channelized turbidites, laterally continuous exposures enabling the distinction to be made. Results of sequence analysis are illustrated by columnar profiles and bed thickness diagrams, i.e. CD (coarse division) and L (layer) diagrams. Eighty percent of channelized cycles show a positive trend, whereas a negative trend characterizes 60% of non channelized cycles. This strengthens the assumption that most positive cycles reflect filling of fan channels, while negative cycles are the expression of prograding depositional lobes, i.e. localized areas of preferred sand accumulation in front of distributary channels. Among progradational cycles, a distinction was made between fast and slow accretion types by means of relative number of beds (L/T ratio), relative number of coarse divisions (L/CD ratio), and frequence of interbedded hemipelagites. The possible non-prograd tional nature of some slower cycles is discussed; they could alternatively reflect sporadic phases of sand accumulation in the basin plain environment due to huge flows triggered by tectonic events and bypassing the fan system (or independent from a fan system). Attempts of correlation of negative cycles both downcurrent and across current are shown.

@article{doi101306212f6cb72b2411d78648000102c1865d,
    author = "Ricci-Lucchi, Franco",
    title = "Depositional cycles in two turbidite formations of northern Apennines",
    year = "1975",
    journal = "Journal of Sedimentary Research",
    abstract = "ABSTRACT Apart from Bouma sequences, recurrent patterns of sedimentation can be recognized at two hierarchic levels in turbidite formations of the northern Apennines. First order cycles (turbidite suites) encompass most of the basin fill, second order cycles (megasequences) occur as organized groups of beds 2-70 m thick within the suites. The Marnoso-arenacea (Lower-Upper Miocene) is an example of a progradational or offlapping suite with thickening and coarsening upward trend. The Laga Formation (Upper Miocene-Lower Pliocene) is characterized by a transgressive (retrogradational) or onlapping trend. Vertical facies changes go either way through the following steps: basin plain outer fan midfan inner fan slope deposits (= prograding, = receding). Both suites are enclosed by hemipelagic pelites and chaotic deposits, the start of turbidite sedimentation being gradual in the progradational case, and abrupt (large scale erosion) in the reverse one. Second order cycles follow each other or are separated by monotonous (uniform or irregularly bedded) sequences of extremely variable thickness (2 to more than 1,000 m) composed either of fan (overbank, fringe) or basin plain deposits (with key beds laterally continuous up to 175 km). The trend of cycles may be asymmetric (termed positive when beds thin upward, negative when they thicken upward), symmetric, composite or not definable. Thick to massive beds with sand/shale ratio >> 1 or > 1 and well developed coarse divisions (products of high density turbidity currents, grain flows, debris flows, fluidized flows) form the thicker bedded portion of cycles and sometimes the whole cycle. One hundred and thirty-two cycles were analyzed and subdivided into simple and complex (= multiple or composite). By splitting multiple cycles into simple components, a total of 170 cycles was reached. Thirty-nine of them were measured in channelized deposits, 131 in non-channelized turbidites, laterally continuous exposures enabling the distinction to be made. Results of sequence analysis are illustrated by columnar profiles and bed thickness diagrams, i.e. CD (coarse division) and L (layer) diagrams. Eighty percent of channelized cycles show a positive trend, whereas a negative trend characterizes 60\% of non channelized cycles. This strengthens the assumption that most positive cycles reflect filling of fan channels, while negative cycles are the expression of prograding depositional lobes, i.e. localized areas of preferred sand accumulation in front of distributary channels. Among progradational cycles, a distinction was made between fast and slow accretion types by means of relative number of beds (L/T ratio), relative number of coarse divisions (L/CD ratio), and frequence of interbedded hemipelagites. The possible non-prograd tional nature of some slower cycles is discussed; they could alternatively reflect sporadic phases of sand accumulation in the basin plain environment due to huge flows triggered by tectonic events and bypassing the fan system (or independent from a fan system). Attempts of correlation of negative cycles both downcurrent and across current are shown.",
    url = "https://doi.org/10.1306/212f6cb7-2b24-11d7-8648000102c1865d",
    doi = "10.1306/212f6cb7-2b24-11d7-8648000102c1865d",
    openalex = "W2016995231"
}

@misc{embley1976new1,
    author = "Embley, R. W",
    title = "New evidence for occurrence of debris flow deposits in the deep sea",
    year = "1976",
    howpublished = "Geology, v. 4, p. 371-374",
    note = "talkorigins\_source = {true}; raw\_reference = {Embley, R. W., 1976, New evidence for occurrence of debris flow deposits in the deep sea: Geology, v. 4, p. 371-374.}"
}

Abstract Five main facies of deep-water clastic rocks can be defined: classic turbidites, massive sandstones, pebbly sandstones, conglomerates, and debris flows (with slumps and slides). The classic turbidites consist of monotonously parallel-interbedded sandstones and shales without channeling; internal sedimentary structures include grading, parallel lamination, and cross-lamination. Massive sandstones are thicker, coarser, and commonly channelized. They lack the sedimentary structures of classic turbidites, but do contain evidence of dewatering during deposition. Pebbly sandstones tend to be well graded, and can contain parallel stratification and large-scale cross-stratification. Conglomerates are characterized by inverse and normal grading, parallel and cross-stratification, and commonly have a preferred clast fabric (imbrication). Both the pebbly sandstones and conglomerates commonly are channelized. The facies can be fitted into a model of submarine-fan deposition. Modern fans are subdivided into an upper fan (suprafan), characterized by (1) a single deep channel with levees, (2) a middle fan, built up from suprafan lobes that periodically switch in position, and (3) a topographically smooth lower fan. The suprafan lobes have shallow, braided channels on their inner parts, but the outer suprafan lobes are smooth, and grade basinward into the smooth lower fan and basin plain. The smooth suprafan lobes and lower fan are characterized by deposition of the classic turbidite facies, and the braided part of the suprafan lobes by massive and pebbly sandstones. When one lobe is abandoned and another starts to prograde elsewhere, the first lobe is blanketed by mud, forming a potential stratigraphic trap. The upper-fan channel is an area of coarse sediment deposition, or conglomerates where gravel and boulders are supplied to the basin. During fan progradation, thickening- and coarsening-upward facies sequences can be formed in a manner analogous to those of deltas. Fan channels also can be abandoned progressively, forming thinning- and fining-upward sequences similar to those of fluvial or distributary channels. These sequences can be identified on electric logs. Where basin shales act as hydrocarbon-source areas, the classic turbidites can act as conduits, leading the hydrocarbons to the thicker, laterally coalesced massive and pebbly sandstones of the braided suprafan lobes. These bodies can be of the order of 25 km in diameter, and up to 100 m thick. The coarse deposits of the upper-fan channel also might form good reservoirs, being bounded by shales (levee deposits) on either side, and possibly by shales above if the fan-channel system is abandoned. Such channels can be tens of kilometers long, several kilometers wide, and a few hundred meters deep. Reservoirs may be present in all of these environments.

@article{doi101306c1ea4f7716c911d78645000102c1865d,
    author = "Walker, Roger G.",
    title = "Deep-Water Sandstone Facies and Ancient Submarine Fans: Models for Exploration for Stratigraphic Traps",
    year = "1978",
    journal = "AAPG Bulletin",
    abstract = "Abstract Five main facies of deep-water clastic rocks can be defined: classic turbidites, massive sandstones, pebbly sandstones, conglomerates, and debris flows (with slumps and slides). The classic turbidites consist of monotonously parallel-interbedded sandstones and shales without channeling; internal sedimentary structures include grading, parallel lamination, and cross-lamination. Massive sandstones are thicker, coarser, and commonly channelized. They lack the sedimentary structures of classic turbidites, but do contain evidence of dewatering during deposition. Pebbly sandstones tend to be well graded, and can contain parallel stratification and large-scale cross-stratification. Conglomerates are characterized by inverse and normal grading, parallel and cross-stratification, and commonly have a preferred clast fabric (imbrication). Both the pebbly sandstones and conglomerates commonly are channelized. The facies can be fitted into a model of submarine-fan deposition. Modern fans are subdivided into an upper fan (suprafan), characterized by (1) a single deep channel with levees, (2) a middle fan, built up from suprafan lobes that periodically switch in position, and (3) a topographically smooth lower fan. The suprafan lobes have shallow, braided channels on their inner parts, but the outer suprafan lobes are smooth, and grade basinward into the smooth lower fan and basin plain. The smooth suprafan lobes and lower fan are characterized by deposition of the classic turbidite facies, and the braided part of the suprafan lobes by massive and pebbly sandstones. When one lobe is abandoned and another starts to prograde elsewhere, the first lobe is blanketed by mud, forming a potential stratigraphic trap. The upper-fan channel is an area of coarse sediment deposition, or conglomerates where gravel and boulders are supplied to the basin. During fan progradation, thickening- and coarsening-upward facies sequences can be formed in a manner analogous to those of deltas. Fan channels also can be abandoned progressively, forming thinning- and fining-upward sequences similar to those of fluvial or distributary channels. These sequences can be identified on electric logs. Where basin shales act as hydrocarbon-source areas, the classic turbidites can act as conduits, leading the hydrocarbons to the thicker, laterally coalesced massive and pebbly sandstones of the braided suprafan lobes. These bodies can be of the order of 25 km in diameter, and up to 100 m thick. The coarse deposits of the upper-fan channel also might form good reservoirs, being bounded by shales (levee deposits) on either side, and possibly by shales above if the fan-channel system is abandoned. Such channels can be tens of kilometers long, several kilometers wide, and a few hundred meters deep. Reservoirs may be present in all of these environments.",
    url = "https://doi.org/10.1306/c1ea4f77-16c9-11d7-8645000102c1865d",
    doi = "10.1306/c1ea4f77-16c9-11d7-8645000102c1865d",
    openalex = "W4253862311",
    references = "doi101086625710, doi101111j136530911975tb00290x, doi101111j136530911976tb00051x, doi101111j136530911977tb00122x, doi10113000167606195970279tdispa20co2, doi101130001676061969801859dfpap20co2, doi10113000167606197586737gfmfrc20co2, doi101144pygs3511, doi101306212f6cb72b2411d78648000102c1865d, doi1013065d25c61516c111d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, doi10130674d716452b2111d78648000102c1865d"
}

@techreport{normark1978fan5,
    author = "Normark, W. R",
    title = "Fan valleys, channels, and depositional lobes on modern submarine fans",
    year = "1978",
    howpublished = "characters for recognition of sandy turbidite environments: American Association of Petroleum Geologists Bulletin, v. 62, p. 912-931",
    note = "talkorigins\_source = {true}; raw\_reference = {Normark, W. R., 1978, Fan valleys, channels, and depositional lobes on modern submarine fans: characters for recognition of sandy turbidite environments: American Association of Petroleum Geologists Bulletin, v. 62, p. 912-931.}"
}

Five main facies of deep-water clastic rocks can be defined: classic turbidites, massive sandstones, pebbly sandstones, conglomerates, and debris flows (with slumps and slides). The classic turbidites consist of monotonously parallel-interbedded sandstones and shales without channeling; internal sedimentary structures include grading, parallel lamination, and cross-lamination. Massive sandstones are thicker, coarser, and commonly channelized. They lack the sedimentary structures of classic turbidites, but do contain evidence of dewatering during deposition. Pebbly sandstones tend to be well graded, and can contain parallel stratification and large-scale cross-stratification. Conglomerates are characterized by inverse and normal grading, parallel and cross-stratification, nd commonly have a preferred clast fabric (imbrication). Both the pebbly sandstones and conglomerates commonly are channelized. The facies can be fitted into a model of submarine-fan deposition. Modern fans are subdivided into an upper fan (suprafan), characterized by (1) a single deep channel with levees, (2) a middle fan, built up from suprafan lobes that periodically switch in position, and (3) a topographically smooth lower fan. The suprafan lobes have shallow, braided channels on their inner parts, but the outer suprafan lobes are smooth, and grade basinward into the smooth lower fan and basin plain. The smooth suprafan lobes and lower fan are characterized by deposition of the classic turbidite facies, and the braided part of the suprafan lobes by massive and pebbly sandstones. When one lobe is abandoned and another starts to prograde elsewhere, the first lobe is blanketed by mud, forming a potential stratigraphic trap. The upper-fan channel is an area of coarse sediment deposition, or conglomerates where gravel and boulders are supplied to the basin. During fan progradation, thickening- and coarsening-upward facies sequences can be formed in a manner analogous to those of deltas. Fan channels also can be abandoned progressively, forming thinning- and fining-upward sequences similar to those of fluvial or distributary channels. These sequences can be identified on electric logs. Where basin shales act as hydrocarbon-source areas, the classic turbidites can act as conduits, leading the hydrocarbons to the thicker, laterally coalesced massive and pebbly sandstones of the braided suprafan lobes. These bodies can be of the order of 25 km in diameter, and up to 100 m thick. The coarse deposits of the upper-fan channel also might form good reservoirs, being bounded by shales (levee deposits) on either side, and possibly by shales above if the fan-channel system is abandoned. Such channels can be tens of kilometers long, several kilometers wide, and a few hundred meters deep. Reservoirs may be present in all of these environments.

@article{doi1013062f9182e316ce11d78645000102c1865d,
    author = "Aalto, K. R.",
    title = "Deep-Water Sandstone Facies and Ancient Submarine Fans: Models for Exploration for Stratigraphic Traps: Discussion",
    year = "1979",
    journal = "AAPG Bulletin",
    abstract = "Five main facies of deep-water clastic rocks can be defined: classic turbidites, massive sandstones, pebbly sandstones, conglomerates, and debris flows (with slumps and slides). The classic turbidites consist of monotonously parallel-interbedded sandstones and shales without channeling; internal sedimentary structures include grading, parallel lamination, and cross-lamination. Massive sandstones are thicker, coarser, and commonly channelized. They lack the sedimentary structures of classic turbidites, but do contain evidence of dewatering during deposition. Pebbly sandstones tend to be well graded, and can contain parallel stratification and large-scale cross-stratification. Conglomerates are characterized by inverse and normal grading, parallel and cross-stratification, nd commonly have a preferred clast fabric (imbrication). Both the pebbly sandstones and conglomerates commonly are channelized. The facies can be fitted into a model of submarine-fan deposition. Modern fans are subdivided into an upper fan (suprafan), characterized by (1) a single deep channel with levees, (2) a middle fan, built up from suprafan lobes that periodically switch in position, and (3) a topographically smooth lower fan. The suprafan lobes have shallow, braided channels on their inner parts, but the outer suprafan lobes are smooth, and grade basinward into the smooth lower fan and basin plain. The smooth suprafan lobes and lower fan are characterized by deposition of the classic turbidite facies, and the braided part of the suprafan lobes by massive and pebbly sandstones. When one lobe is abandoned and another starts to prograde elsewhere, the first lobe is blanketed by mud, forming a potential stratigraphic trap. The upper-fan channel is an area of coarse sediment deposition, or conglomerates where gravel and boulders are supplied to the basin. During fan progradation, thickening- and coarsening-upward facies sequences can be formed in a manner analogous to those of deltas. Fan channels also can be abandoned progressively, forming thinning- and fining-upward sequences similar to those of fluvial or distributary channels. These sequences can be identified on electric logs. Where basin shales act as hydrocarbon-source areas, the classic turbidites can act as conduits, leading the hydrocarbons to the thicker, laterally coalesced massive and pebbly sandstones of the braided suprafan lobes. These bodies can be of the order of 25 km in diameter, and up to 100 m thick. The coarse deposits of the upper-fan channel also might form good reservoirs, being bounded by shales (levee deposits) on either side, and possibly by shales above if the fan-channel system is abandoned. Such channels can be tens of kilometers long, several kilometers wide, and a few hundred meters deep. Reservoirs may be present in all of these environments.",
    url = "https://doi.org/10.1306/2f9182e3-16ce-11d7-8645000102c1865d",
    doi = "10.1306/2f9182e3-16ce-11d7-8645000102c1865d",
    openalex = "W2056452793",
    references = "doi1010160016714277900096, doi101086625710, doi101111j136530911975tb00290x, doi101111j136530911976tb00051x, doi101111j136530911977tb00122x, doi101130001676061969801859dfpap20co2, doi10113000167606197586737gfmfrc20co2, doi1013065d25c0f916c111d78645000102c1865d, doi1013065d25c2d316c111d78645000102c1865d, doi1013065d25c61516c111d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, doi10130674d7262b2b2111d78648000102c1865d, doi102110scn7502, openalexw3120543430, paine1968stratigraphy"
}

@article{nardin1979a3,
    author = "Nardin, T. R. and Hein, F. J. and Gorsline, D. S. and Edwards, B. D",
    title = "A review of mass movement processes, sediment and acoustic characteristics, and contrasts in slope and base-of-slope systems versus canyon-fan-basin floor systems, in Geology of Continental Slopes",
    year = "1979",
    journal = "SEPM Special Publication 27, p. 61-73",
    note = "talkorigins\_source = {true}; raw\_reference = {Nardin, T. R., Hein, F. J., Gorsline, D. S., and Edwards, B. D., 1979, A review of mass movement processes, sediment and acoustic characteristics, and contrasts in slope and base-of-slope systems versus canyon-fan-basin floor systems, in Geology of Continental Slopes: SEPM Special Publication 27, p. 61-73.}"
}

ABSTRACT Four principal mechanisms of deposition are effective in the formation of sediment gravity flow deposits. Grains deposited by traction sedimentation and suspension sedimentation respond individually and accumulate directly from bed and suspended loads, respectively. Those deposited by frictional freezing and cohesive freezing interact through either frictional contact or cohesive forces, respectively, and are deposited collectively, usually by plug formation. Sediment deposition from individual sediment flows commonly involves more than one of these mechanisms acting either serially as the flow evolves or simultaneously on different grain populations. Deposition from turbidity currents is treated in terms of three dynamic grain populations: 1) clay- to medium-grained sand-sized particles that can be fully suspended as individual grains by flow turbulence, 2) coarse-grained sand to small-pebble-sized gravel that can be fully suspended in large amounts mainly in highly concentrated turbulent suspensions where grain fall velocity is substantially reduced by hindered settling, and 3) pebble- and cobble-sized clasts having concentrations greater than 10 percent to 15 percent that will be supported largely by dispersive pressure resulting from clast collisions and by buoyant lift provided by the interstitial mixture of water and finer-grained sediment. The effects of hindered settling, dispersive pressure, and matrix buoyant lift are con entration dependent, and grain populations 2 and 3 are likely to be transported in large amounts only within flows having high particle concentrations, probably in excess of 20 percent solids by volume. Low-density turbidity currents, made up largely of grains of population 1, typically show an initial period of traction sedimentation, forming Bouma (Tb) and Tc) divisions, followed by one of mixed traction and suspension sedimentation (Td), and a terminal period of fine-grained suspension sedimentation (Te). The sediment loads of high-density turbidity currents commonly include grains belonging to populations 1, 2, and 3. Consequently, deposition often occurs as a series of discrete sedimentation waves as flows decelerate and individual grain populations can no longer be maintained in transport. Each sedimentation wave tends to show increasing unsteadiness and accelerating sedimentation rate as it evolves, passing from an initial stage of traction sedimentation, to one of mixed frictional freezing and suspension sedimentation within traction carpets, to a final stage of direct suspension sedimentation. Sequences of sedimentary structure divisions representing this succession of depositional stages are here termed the ecoR1-3) sequence, representing population 3 grains, and the S1-3) sequence, representing population 2. Deposition of the high-density suspended load leaves behind a residual low-density turbidity current composed largely of population 1 grains. At their distal ends, high-density turbidity currents deposit mainly by suspension sedimentation, forming thin (S3) divisions. These (S3) divisions are the same as Bouma (Ta) and, if subsequently capped by (Tb-e) deposited by the residual low-density flows, become the basal divisions of normal turbidities. Liquefied flows deposit by direct high-density suspension sedimentation. Grain flows of sand are characterized by frictional freezing and their deposits are limited mainly to angle-of-repose slipface units. Density-modified grain flows, in which larger clasts are partially supported by matrix buoyancy, and traction carpets, in which a dense frictional grain dispersion is driven by an overlying turbulent flow, are important in the buildup of natural deposits on submarine slopes. Cohesive debris flows depost sediment mainly by cohesive freezing, commonly modified by suspension sedimentation of the largest clasts.

@article{doi101306212f7f312b2411d78648000102c1865d,
    author = "Lowe, Donald R.",
    title = "Sediment Gravity Flows: II Depositional Models with Special Reference to the Deposits of High-Density Turbidity Currents",
    year = "1982",
    journal = "Journal of Sedimentary Research",
    abstract = "ABSTRACT Four principal mechanisms of deposition are effective in the formation of sediment gravity flow deposits. Grains deposited by traction sedimentation and suspension sedimentation respond individually and accumulate directly from bed and suspended loads, respectively. Those deposited by frictional freezing and cohesive freezing interact through either frictional contact or cohesive forces, respectively, and are deposited collectively, usually by plug formation. Sediment deposition from individual sediment flows commonly involves more than one of these mechanisms acting either serially as the flow evolves or simultaneously on different grain populations. Deposition from turbidity currents is treated in terms of three dynamic grain populations: 1) clay- to medium-grained sand-sized particles that can be fully suspended as individual grains by flow turbulence, 2) coarse-grained sand to small-pebble-sized gravel that can be fully suspended in large amounts mainly in highly concentrated turbulent suspensions where grain fall velocity is substantially reduced by hindered settling, and 3) pebble- and cobble-sized clasts having concentrations greater than 10 percent to 15 percent that will be supported largely by dispersive pressure resulting from clast collisions and by buoyant lift provided by the interstitial mixture of water and finer-grained sediment. The effects of hindered settling, dispersive pressure, and matrix buoyant lift are con entration dependent, and grain populations 2 and 3 are likely to be transported in large amounts only within flows having high particle concentrations, probably in excess of 20 percent solids by volume. Low-density turbidity currents, made up largely of grains of population 1, typically show an initial period of traction sedimentation, forming Bouma (Tb) and Tc) divisions, followed by one of mixed traction and suspension sedimentation (Td), and a terminal period of fine-grained suspension sedimentation (Te). The sediment loads of high-density turbidity currents commonly include grains belonging to populations 1, 2, and 3. Consequently, deposition often occurs as a series of discrete sedimentation waves as flows decelerate and individual grain populations can no longer be maintained in transport. Each sedimentation wave tends to show increasing unsteadiness and accelerating sedimentation rate as it evolves, passing from an initial stage of traction sedimentation, to one of mixed frictional freezing and suspension sedimentation within traction carpets, to a final stage of direct suspension sedimentation. Sequences of sedimentary structure divisions representing this succession of depositional stages are here termed the ecoR1-3) sequence, representing population 3 grains, and the S1-3) sequence, representing population 2. Deposition of the high-density suspended load leaves behind a residual low-density turbidity current composed largely of population 1 grains. At their distal ends, high-density turbidity currents deposit mainly by suspension sedimentation, forming thin (S3) divisions. These (S3) divisions are the same as Bouma (Ta) and, if subsequently capped by (Tb-e) deposited by the residual low-density flows, become the basal divisions of normal turbidities. Liquefied flows deposit by direct high-density suspension sedimentation. Grain flows of sand are characterized by frictional freezing and their deposits are limited mainly to angle-of-repose slipface units. Density-modified grain flows, in which larger clasts are partially supported by matrix buoyancy, and traction carpets, in which a dense frictional grain dispersion is driven by an overlying turbulent flow, are important in the buildup of natural deposits on submarine slopes. Cohesive debris flows depost sediment mainly by cohesive freezing, commonly modified by suspension sedimentation of the largest clasts.",
    url = "https://doi.org/10.1306/212f7f31-2b24-11d7-8648000102c1865d",
    doi = "10.1306/212f7f31-2b24-11d7-8648000102c1865d",
    openalex = "W2087125749"
}

ABSTRACT The late Pleistocene and Holocene stratigraphy of Navy Fan is mapped in detail from more than 100 cores. Thirteen 14 C dates of plant detritus and of organic‐rich mud beds show that a marked change in sediment supply from sandy to muddy turbidites occurred between 9000 and 12,000 years ago. They also confirm the correlation of several individual depositional units. The sediment dispersal pattern is primarily controlled by basin configuration and fan morphology, particularly the geometry of distributary channels, which show abrupt 60° bends related to the Pleistocene history of lobe progradation. The Holocene turbidity currents are depositing on, and modifying only slightly, a relict Pleistocene morphology. The uppermost turbidite is a thin sand to mud bed on the upper‐fan valley levées and on parts of the mid‐fan. Most of its sediment volume is in a mud bed on the lower fan and basin plain downslope from a sharp bend in the mid‐fan distributary system. Little sediment occurs farther downstream within this distributary system. It appears that most of the turbidity current overtopped the levée at the channel bend, a process referred to as flow stripping. The muddy upper part of the flow continued straight down to the basin plain. The residual more sandy base of the flow in the distributary channel was not thick enough to maintain itself as gradient decreased and the channel opened out on to the mid‐fan lobe. Flow stripping may occur in any turbidity current that is thick relative to channel depth and that flows in a channel with sharp bends. Where thick sandy currents are stripped, levée and mid‐fan erosion may occur, but the residual current in the channel will lose much of its power and deposit rapidly. In thick muddy currents, progressive overflow of mud will cause less declaration of the residual channelised current. Thus both size and sand‐to‐mud ratio of turbidity currents feeding a fan are important factors controlling morphologic features and depositional areas on fans. The size‐frequency variation for different types of turbidity currents is estimated from the literature and related to the evolution of fan morphology.

@article{doi101111j136530911983tb00702x,
    author = "Piper, David J. W. and Normark, William R.",
    title = "Turbidite depositional patterns and flow characteristics, Navy Submarine Fan, California Borderland",
    year = "1983",
    journal = "Sedimentology",
    abstract = "ABSTRACT The late Pleistocene and Holocene stratigraphy of Navy Fan is mapped in detail from more than 100 cores. Thirteen 14 C dates of plant detritus and of organic‐rich mud beds show that a marked change in sediment supply from sandy to muddy turbidites occurred between 9000 and 12,000 years ago. They also confirm the correlation of several individual depositional units. The sediment dispersal pattern is primarily controlled by basin configuration and fan morphology, particularly the geometry of distributary channels, which show abrupt 60° bends related to the Pleistocene history of lobe progradation. The Holocene turbidity currents are depositing on, and modifying only slightly, a relict Pleistocene morphology. The uppermost turbidite is a thin sand to mud bed on the upper‐fan valley levées and on parts of the mid‐fan. Most of its sediment volume is in a mud bed on the lower fan and basin plain downslope from a sharp bend in the mid‐fan distributary system. Little sediment occurs farther downstream within this distributary system. It appears that most of the turbidity current overtopped the levée at the channel bend, a process referred to as flow stripping. The muddy upper part of the flow continued straight down to the basin plain. The residual more sandy base of the flow in the distributary channel was not thick enough to maintain itself as gradient decreased and the channel opened out on to the mid‐fan lobe. Flow stripping may occur in any turbidity current that is thick relative to channel depth and that flows in a channel with sharp bends. Where thick sandy currents are stripped, levée and mid‐fan erosion may occur, but the residual current in the channel will lose much of its power and deposit rapidly. In thick muddy currents, progressive overflow of mud will cause less declaration of the residual channelised current. Thus both size and sand‐to‐mud ratio of turbidity currents feeding a fan are important factors controlling morphologic features and depositional areas on fans. The size‐frequency variation for different types of turbidity currents is estimated from the literature and related to the evolution of fan morphology.",
    url = "https://doi.org/10.1111/j.1365-3091.1983.tb00702.x",
    doi = "10.1111/j.1365-3091.1983.tb00702.x",
    openalex = "W2103765846",
    references = "doi101016001174717090001x, doi1010160019103580900974, doi1010160025322776900633, doi101086627725, doi101111j136530911979tb00971x, doi10113000167606197485859lcotpe20co2, doi101130001676061976871291cotthb20co2, doi101130001676061979901165bsthap20co2, doi101306212f79b42b2411d78648000102c1865d, openalexw3120543430"
}

Part 1 Facies, processes, sequences and controls: sediment transport and deposition deep-water facies and depositional processes controls on sedimentation and sequences. Part 2 Deep-water basin elements: slope aprons and slope basins submarine canyons, gullies and valleys submarine fans sheet systems contourite drifts. Part 3 Plate tectonics and sedimentation: evolving and mature passive margins active convergent margins oblique-slip margins.

@book{openalexw1912503598,
    author = "Pickering, K.T. and Hiscott, Richard N. and Hein, Frances J.",
    title = "Deep Marine Environments: Clastic sedimentation and tectonics",
    year = "1989",
    abstract = "Part 1 Facies, processes, sequences and controls: sediment transport and deposition deep-water facies and depositional processes controls on sedimentation and sequences. Part 2 Deep-water basin elements: slope aprons and slope basins submarine canyons, gullies and valleys submarine fans sheet systems contourite drifts. Part 3 Plate tectonics and sedimentation: evolving and mature passive margins active convergent margins oblique-slip margins.",
    openalex = "W1912503598"
}

ABSTRACT The Mississippi Fan is a large, mud-dominated submarine fan over 4 km thick that was deposited in the deep Gulf of Mexico during the late Pliocene and Pleistocene. Analysis of 19000 km of multifold seismic data across the fan defined 17 seismic sequences, each characterized by a series of channel, levee, and associated overbank deposits, along with other mass transport deposits. At the base of nine sequences are a series of seismic facies consisting of mounded, hummocky, chaotic, and subparallel reflections, which constitute 10–20% of the sediments in the sequence. These facies are externally mounded in cross section and occur in two general regions of the fan. In the upper and middle fan, they occur below channels and are elongated in shape, mimicking the channel’s distribution. In the middle to lower fan, they have a fan-shaped distribution, increasing in width downfan. These facies are interpreted to have formed as disorganized slides, debris flows, and turbidites, and are informally called mass transport complexes. Overlying this basal interval and characteristic of all sequences are well-developed channel-levee systems, which constitute 80–90% of the fan’s sediments. Channels consist of high-amplitude, subparallel reflections. Levee sediments have subparallel reflections that have moderate to high amplitudes at the base changing upward to low amplitude. The vertical change in amplitude may reflect a decrease in the grain size and bed thickness of the levee sediments. Overbank sediments consist of interbedded subparallel to hummocky and mounded reflections, suggesting both turbidites derived from the channel, as well as slides and debris flows derived from the slope. Pliocene–Pleistocene eustatic cycles are interpreted to have been the major factor controlling the timing and style of sedimentation in the fan. Mass transport complexes are interpreted to have formed during a lowering of sea level, and reflect sediments derived from retrogressive slumping during the formation of submarine canyons in the upper slope and outer shelf. Channel-levee systems were deposited when sea level was near its lowest position and sediment derived from deltas was transported into the deep basin via submarine canyons. During highstands in sea level, a thin layer of hemipelagic sediment was deposited on the fan surface. The Mississippi Fan serves as an exploration model for mud-dominated submarine fans and has four prospective reservoir facies: channel sands with linear trends, unchannelized sands beyond the downdip terminus of the channel (possible lobes), potentially sand-prone levees immediately adjacent to initial channels deposited in some sequences, and limited parts of mass transport complexes.

@article{doi1013060c9b2321171011d78645000102c1865d,
    author = "Weimer, Paul",
    title = "Sequence Stratigraphy, Facies Geometries, and Depositional History of the Mississippi Fan, Gulf of Mexico",
    year = "1990",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT The Mississippi Fan is a large, mud-dominated submarine fan over 4 km thick that was deposited in the deep Gulf of Mexico during the late Pliocene and Pleistocene. Analysis of 19000 km of multifold seismic data across the fan defined 17 seismic sequences, each characterized by a series of channel, levee, and associated overbank deposits, along with other mass transport deposits. At the base of nine sequences are a series of seismic facies consisting of mounded, hummocky, chaotic, and subparallel reflections, which constitute 10–20\% of the sediments in the sequence. These facies are externally mounded in cross section and occur in two general regions of the fan. In the upper and middle fan, they occur below channels and are elongated in shape, mimicking the channel’s distribution. In the middle to lower fan, they have a fan-shaped distribution, increasing in width downfan. These facies are interpreted to have formed as disorganized slides, debris flows, and turbidites, and are informally called mass transport complexes. Overlying this basal interval and characteristic of all sequences are well-developed channel-levee systems, which constitute 80–90\% of the fan’s sediments. Channels consist of high-amplitude, subparallel reflections. Levee sediments have subparallel reflections that have moderate to high amplitudes at the base changing upward to low amplitude. The vertical change in amplitude may reflect a decrease in the grain size and bed thickness of the levee sediments. Overbank sediments consist of interbedded subparallel to hummocky and mounded reflections, suggesting both turbidites derived from the channel, as well as slides and debris flows derived from the slope. Pliocene–Pleistocene eustatic cycles are interpreted to have been the major factor controlling the timing and style of sedimentation in the fan. Mass transport complexes are interpreted to have formed during a lowering of sea level, and reflect sediments derived from retrogressive slumping during the formation of submarine canyons in the upper slope and outer shelf. Channel-levee systems were deposited when sea level was near its lowest position and sediment derived from deltas was transported into the deep basin via submarine canyons. During highstands in sea level, a thin layer of hemipelagic sediment was deposited on the fan surface. The Mississippi Fan serves as an exploration model for mud-dominated submarine fans and has four prospective reservoir facies: channel sands with linear trends, unchannelized sands beyond the downdip terminus of the channel (possible lobes), potentially sand-prone levees immediately adjacent to initial channels deposited in some sequences, and limited parts of mass transport complexes.",
    url = "https://doi.org/10.1306/0c9b2321-1710-11d7-8645000102c1865d",
    doi = "10.1306/0c9b2321-1710-11d7-8645000102c1865d",
    openalex = "W2121411543",
    references = "doi1010079781461251149, doi10100797814684827684, doi10100797894009324181, doi10100797894017280964, doi101007bf02431072, doi1010160025322771900533, doi1010160031018288900089, doi10113000167606198798728qcosdc20co2, doi10130603b59a5816d111d78645000102c1865d, doi101306703c9109170711d78645000102c1865d, doi101306703c910e170711d78645000102c1865d, doi10130694887889170411d78645000102c1865d, doi1040435695ms"
}

@incollection{kolla1990lowstand,
    author = "KOLLA, V. and MARTIN, R. and WEIMER, P.",
    title = "Lowstand Deep-Water Clastic Fans and Related Depositional Systems: Terminology, Characteristics, Processes, and Variability",
    year = "1990",
    booktitle = "Sequence Stratigraphy as an Exploration Tool: Concepts and Practices in the Gulf Coast: 11th Annual",
    url = "https://doi.org/10.5724/gcs.90.11.0213",
    doi = "10.5724/gcs.90.11.0213",
    openalex = "W2132352100",
    pages = "213-215"
}

ABSTRACT Depositional systems in deep-water basin margins can be classified on the basis of grain size and feeder system into 12 classes: mud-rich, mud/sand-rich, sand-rich, and gravel-rich “point-source submarine fans;” mud-rich, mud/sand-rich, sand-rich, and gravel-rich “multiple-source submarine ramps;” and mud-rich, mud/sand-rich, sand-rich, and gravel-rich “linear-source slope aprons.” The size and stability of channels and the organization of the depositional sequences decreases toward a linear source as does the length:width ratio of the system. As grain size increases, so does slope gradient, impersistence of channel systems, and tendency for channels to migrate. As grain size diminishes, there is an increase in the size of the source area, the size of the depositional system, the downcurrent length, the persistence and size of flows, fan channels, channel-levee systems, and in the tendency to meander and for major slumps and sheet sands to reach the lower fan and basin plain. The exact positioning of any one depositional system within the scheme cannot always be precise, and the position may be altered by changes in tectonics, climate, supply, and sea level. However, the models derived from each system are sufficiently different to significantly affect the nature of petroleum prospectivity and reservoir pattern. Understanding and recognizing this variability is crucial to all elements of the exploration-production chain. In exploration, initial evaluations of prospectivity and commerciality rely on the accurate stratigraphic prediction of reservoir facies, architecture, and trapping styles. For field appraisal and reservoir development, a similar appreciation of variability aids reservoir description by capturing the distribution and architecture of reservoir and nonreservoir facies and their impact on reservoir delineation, reservoir behavior, and production performance.

@article{doi101306a25fe3bf171b11d78645000102c1865d,
    author = "Reading, Harold G. and Richards, Marcus",
    title = "Turbidite Systems in Deep-Water Basin Margins Classified by Grain Size and Feeder System",
    year = "1994",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT Depositional systems in deep-water basin margins can be classified on the basis of grain size and feeder system into 12 classes: mud-rich, mud/sand-rich, sand-rich, and gravel-rich “point-source submarine fans;” mud-rich, mud/sand-rich, sand-rich, and gravel-rich “multiple-source submarine ramps;” and mud-rich, mud/sand-rich, sand-rich, and gravel-rich “linear-source slope aprons.” The size and stability of channels and the organization of the depositional sequences decreases toward a linear source as does the length:width ratio of the system. As grain size increases, so does slope gradient, impersistence of channel systems, and tendency for channels to migrate. As grain size diminishes, there is an increase in the size of the source area, the size of the depositional system, the downcurrent length, the persistence and size of flows, fan channels, channel-levee systems, and in the tendency to meander and for major slumps and sheet sands to reach the lower fan and basin plain. The exact positioning of any one depositional system within the scheme cannot always be precise, and the position may be altered by changes in tectonics, climate, supply, and sea level. However, the models derived from each system are sufficiently different to significantly affect the nature of petroleum prospectivity and reservoir pattern. Understanding and recognizing this variability is crucial to all elements of the exploration-production chain. In exploration, initial evaluations of prospectivity and commerciality rely on the accurate stratigraphic prediction of reservoir facies, architecture, and trapping styles. For field appraisal and reservoir development, a similar appreciation of variability aids reservoir description by capturing the distribution and architecture of reservoir and nonreservoir facies and their impact on reservoir delineation, reservoir behavior, and production performance.",
    url = "https://doi.org/10.1306/a25fe3bf-171b-11d7-8645000102c1865d",
    doi = "10.1306/a25fe3bf-171b-11d7-8645000102c1865d",
    openalex = "W2112508324",
    references = "doi1010160012825288900645, doi101111j136530911983tb00702x, doi101111j136530911993tb01347x, doi10113000167606198394459ftaspi20co2, doi10130603b5b6aa16d111d78645000102c1865d, doi1013060c9b2321171011d78645000102c1865d, doi1013062f9182e316ce11d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, doi101306703c9109170711d78645000102c1865d, doi101306819a41a216c511d78645000102c1865d, doi101306ad4619e916f711d78645000102c1865d, doi101306ad462b3716f711d78645000102c1865d, doi101306bdff8e16171811d78645000102c1865d, normark1978fan, openalexw425049407"
}

Abstract Sandstones deposited in deep marine environments form important hydrocarbon reservoirs in many basins throughout the world. However, despite the plethora of outcrop studies and the development of numerous submarine fan models and classification schemes, very few applied studies at a reservoir scale have been published. This publication has arisen from the perceived needs of the academic and industrial communities to understand the controls on the architecture and geometry of deep marine clastic reservoirs. A number of areas of concern have been addressed: (1) Are conceptual models applicable to understanding sandstone body development and distribution at a reservoir scale? (2) Do we understand the processes that are active in the formation of deep marine clastic systems and the likely influence of these processes on reservoir quality? (3) How do we correlate and at what scale do correlation mechanisms work within and between deep marine clastic reservoirs? (4) How can we quantify heterogeneity and reservoir quality within these reservoirs?

@article{doi101144gslsp19950940101,
    author = "Hartley, Adrian J. and Prosser, J.",
    title = "Characterization of deep marine clastic systems",
    year = "1995",
    journal = "Geological Society London Special Publications",
    abstract = "Abstract Sandstones deposited in deep marine environments form important hydrocarbon reservoirs in many basins throughout the world. However, despite the plethora of outcrop studies and the development of numerous submarine fan models and classification schemes, very few applied studies at a reservoir scale have been published. This publication has arisen from the perceived needs of the academic and industrial communities to understand the controls on the architecture and geometry of deep marine clastic reservoirs. A number of areas of concern have been addressed: (1) Are conceptual models applicable to understanding sandstone body development and distribution at a reservoir scale? (2) Do we understand the processes that are active in the formation of deep marine clastic systems and the likely influence of these processes on reservoir quality? (3) How do we correlate and at what scale do correlation mechanisms work within and between deep marine clastic reservoirs? (4) How can we quantify heterogeneity and reservoir quality within these reservoirs?",
    url = "https://doi.org/10.1144/gsl.sp.1995.094.01.01",
    doi = "10.1144/gsl.sp.1995.094.01.01",
    openalex = "W2032337494"
}

Recent advances in theory and experimentation motivate a thorough reassessment of the physics of debris flows. Analyses of flows of dry, granular solids and solid‐fluid mixtures provide a foundation for a comprehensive debris flow theory, and experiments provide data that reveal the strengths and limitations of theoretical models. Both debris flow materials and dry granular materials can sustain shear stresses while remaining static; both can deform in a slow, tranquil mode characterized by enduring, frictional grain contacts; and both can flow in a more rapid, agitated mode characterized by brief, inelastic grain collisions. In debris flows, however, pore fluid that is highly viscous and nearly incompressible, composed of water with suspended silt and clay, can strongly mediate intergranular friction and collisions. Grain friction, grain collisions, and viscous fluid flow may transfer significant momentum simultaneously. Both the vibrational kinetic energy of solid grains (measured by a quantity termed the granular temperature) and the pressure of the intervening pore fluid facilitate motion of grains past one another, thereby enhancing debris flow mobility. Granular temperature arises from conversion of flow translational energy to grain vibrational energy, a process that depends on shear rates, grain properties, boundary conditions, and the ambient fluid viscosity and pressure. Pore fluid pressures that exceed static equilibrium pressures result from local or global debris contraction. Like larger, natural debris flows, experimental debris flows of ∼10 m³ of poorly sorted, water‐saturated sediment invariably move as an unsteady surge or series of surges. Measurements at the base of experimental flows show that coarse‐grained surge fronts have little or no pore fluid pressure. In contrast, finer‐grained, thoroughly saturated debris behind surge fronts is nearly liquefied by high pore pressure, which persists owing to the great compressibility and moderate permeability of the debris. Realistic models of debris flows therefore require equations that simulate inertial motion of surges in which high‐resistance fronts dominated by solid forces impede the motion of low‐resistance tails more strongly influenced by fluid forces. Furthermore, because debris flows characteristically originate as nearly rigid sediment masses, transform at least partly to liquefied flows, and then transform again to nearly rigid deposits, acceptable models must simulate an evolution of material behavior without invoking preternatural changes in material properties. A simple model that satisfies most of these criteria uses depth‐averaged equations of motion patterned after those of the Savage‐Hutter theory for gravity‐driven flow of dry granular masses but generalized to include the effects of viscous pore fluid with varying pressure. These equations can describe a spectrum of debris flow behaviors intermediate between those of wet rock avalanches and sediment‐laden water floods. With appropriate pore pressure distributions the equations yield numerical solutions that successfully predict unsteady, nonuniform motion of experimental debris flows.

@article{doi10102997rg00426,
    author = "Iverson, Richard M.",
    title = "The physics of debris flows",
    year = "1997",
    journal = "Reviews of Geophysics",
    abstract = "Recent advances in theory and experimentation motivate a thorough reassessment of the physics of debris flows. Analyses of flows of dry, granular solids and solid‐fluid mixtures provide a foundation for a comprehensive debris flow theory, and experiments provide data that reveal the strengths and limitations of theoretical models. Both debris flow materials and dry granular materials can sustain shear stresses while remaining static; both can deform in a slow, tranquil mode characterized by enduring, frictional grain contacts; and both can flow in a more rapid, agitated mode characterized by brief, inelastic grain collisions. In debris flows, however, pore fluid that is highly viscous and nearly incompressible, composed of water with suspended silt and clay, can strongly mediate intergranular friction and collisions. Grain friction, grain collisions, and viscous fluid flow may transfer significant momentum simultaneously. Both the vibrational kinetic energy of solid grains (measured by a quantity termed the granular temperature) and the pressure of the intervening pore fluid facilitate motion of grains past one another, thereby enhancing debris flow mobility. Granular temperature arises from conversion of flow translational energy to grain vibrational energy, a process that depends on shear rates, grain properties, boundary conditions, and the ambient fluid viscosity and pressure. Pore fluid pressures that exceed static equilibrium pressures result from local or global debris contraction. Like larger, natural debris flows, experimental debris flows of ∼10 m³ of poorly sorted, water‐saturated sediment invariably move as an unsteady surge or series of surges. Measurements at the base of experimental flows show that coarse‐grained surge fronts have little or no pore fluid pressure. In contrast, finer‐grained, thoroughly saturated debris behind surge fronts is nearly liquefied by high pore pressure, which persists owing to the great compressibility and moderate permeability of the debris. Realistic models of debris flows therefore require equations that simulate inertial motion of surges in which high‐resistance fronts dominated by solid forces impede the motion of low‐resistance tails more strongly influenced by fluid forces. Furthermore, because debris flows characteristically originate as nearly rigid sediment masses, transform at least partly to liquefied flows, and then transform again to nearly rigid deposits, acceptable models must simulate an evolution of material behavior without invoking preternatural changes in material properties. A simple model that satisfies most of these criteria uses depth‐averaged equations of motion patterned after those of the Savage‐Hutter theory for gravity‐driven flow of dry granular masses but generalized to include the effects of viscous pore fluid with varying pressure. These equations can describe a spectrum of debris flow behaviors intermediate between those of wet rock avalanches and sediment‐laden water floods. With appropriate pore pressure distributions the equations yield numerical solutions that successfully predict unsteady, nonuniform motion of experimental debris flows.",
    url = "https://doi.org/10.1029/97rg00426",
    doi = "10.1029/97rg00426",
    openalex = "W2097033979",
    references = "doi1010029781119832348, doi10100797836426975939, doi1010160021916971901899, doi1010160040195171900382, doi1010160377027384900027, doi101017s0022112084000586, doi10102995rg03287, doi101029rg014i002p00227, doi10106311712886, doi1010970001069419750800000022, doi101098rspa19540186, doi101130reg7p1, doi101177030913338300700401, doi102136sssaj197303615995003700040004x, doi102136sssaj197603615995004000040003x, doi103133pp1547, openalexw1548487652, openalexw1555930968"
}

▪ Abstract Field observations, laboratory experiments, and theoretical analyses indicate that landslides mobilize to form debris flows by three processes: (a) widespread Coulomb failure within a sloping soil, rock, or sediment mass, (b) partial or complete liquefaction of the mass by high pore-fluid pressures, and (c) conversion of landslide translational energy to internal vibrational energy (i.e. granular temperature). These processes can operate independently, but in many circumstances they appear to operate simultaneously and synergistically. Early work on debris-flow mobilization described a similar interplay of processes but relied on mechanical models in which debris behavior was assumed to be fixed and governed by a Bingham or Bagnold rheology. In contrast, this review emphasizes models in which debris behavior evolves in response to changing pore pressures and granular temperatures. One-dimensional infinite-slope models provide insight by quantifying how pore pressures and granular temperatures can influence the transition from Coulomb failure to liquefaction. Analyses of multidimensional experiments reveal complications ignored in one-dimensional models and demonstrate that debris-flow mobilization may occur by at least two distinct modes in the field.

@article{doi101146annurevearth25185,
    author = "Iverson, Richard M. and Reid, Mark E. and LaHusen, Richard G.",
    title = "DEBRIS-FLOW MOBILIZATION FROM LANDSLIDES",
    year = "1997",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "▪ Abstract Field observations, laboratory experiments, and theoretical analyses indicate that landslides mobilize to form debris flows by three processes: (a) widespread Coulomb failure within a sloping soil, rock, or sediment mass, (b) partial or complete liquefaction of the mass by high pore-fluid pressures, and (c) conversion of landslide translational energy to internal vibrational energy (i.e. granular temperature). These processes can operate independently, but in many circumstances they appear to operate simultaneously and synergistically. Early work on debris-flow mobilization described a similar interplay of processes but relied on mechanical models in which debris behavior was assumed to be fixed and governed by a Bingham or Bagnold rheology. In contrast, this review emphasizes models in which debris behavior evolves in response to changing pore pressures and granular temperatures. One-dimensional infinite-slope models provide insight by quantifying how pore pressures and granular temperatures can influence the transition from Coulomb failure to liquefaction. Analyses of multidimensional experiments reveal complications ignored in one-dimensional models and demonstrate that debris-flow mobilization may occur by at least two distinct modes in the field.",
    url = "https://doi.org/10.1146/annurev.earth.25.1.85",
    doi = "10.1146/annurev.earth.25.1.85",
    openalex = "W2021675301",
    references = "doi10102997rg00426, doi10108004353676198011879996, doi101130reg7p1, openalexw1555930968"
}

The postglacial Quaternary colluvial systems in western Norway are arrays of steep fans, often coalescing into aprons, developed along the slopes of valley sides and fjord margins. The coarse debris, derived from weathered gneissic bedrock and its glacial‐till mantle, varies from highly immature to mature. The depositional processes are mainly avalanches, ranging from rockfalls and debrisflows to snowflows, but include also waterflow and debris creep. The mechanics and sedimentary products of these processes are discussed, with special emphasis on snow avalanches, whose role as an agent of debris transport is little‐known to sedimentologists. The subsequent analysis of sedimentary successions is focused on colluvial‐fan deltas, which are very specific, yet little‐studied, coastal depositional systems. The stratigraphic variation and depositional architecture of the colluvial facies assemblages, constrained by abundant radiometric dates, are used to decipher the signal of regional climatic changes from the sedimentary record. The stratigraphic data from two dozen local colluvial successions are compiled and further compared with other types of regional palaeoclimatic proxy record. The analysis suggests that the colluvial systems, although dependent upon local geomorphic conditions, have acted as highly sensitive recorders of regional climatic changes. The study as a whole demonstrates that colluvial depositional systems are an interesting and important frontier of clastic sedimentology.

@article{doi101046j13653091199800200x,
    author = "BLIKRA and Nemec",
    title = "Postglacial colluvium in western Norway: depositional processes, facies and palaeoclimatic record",
    year = "1998",
    journal = "Sedimentology",
    abstract = "The postglacial Quaternary colluvial systems in western Norway are arrays of steep fans, often coalescing into aprons, developed along the slopes of valley sides and fjord margins. The coarse debris, derived from weathered gneissic bedrock and its glacial‐till mantle, varies from highly immature to mature. The depositional processes are mainly avalanches, ranging from rockfalls and debrisflows to snowflows, but include also waterflow and debris creep. The mechanics and sedimentary products of these processes are discussed, with special emphasis on snow avalanches, whose role as an agent of debris transport is little‐known to sedimentologists. The subsequent analysis of sedimentary successions is focused on colluvial‐fan deltas, which are very specific, yet little‐studied, coastal depositional systems. The stratigraphic variation and depositional architecture of the colluvial facies assemblages, constrained by abundant radiometric dates, are used to decipher the signal of regional climatic changes from the sedimentary record. The stratigraphic data from two dozen local colluvial successions are compiled and further compared with other types of regional palaeoclimatic proxy record. The analysis suggests that the colluvial systems, although dependent upon local geomorphic conditions, have acted as highly sensitive recorders of regional climatic changes. The study as a whole demonstrates that colluvial depositional systems are an interesting and important frontier of clastic sedimentology.",
    url = "https://doi.org/10.1046/j.1365-3091.1998.00200.x",
    doi = "10.1046/j.1365-3091.1998.00200.x",
    openalex = "W2153106841",
    references = "doi102110scn7502, openalexw1598633756"
}

Continental slope sediment failures around the epicentre of the 1929 ‘Grand Banks’ earthquake have been imaged with the SAR (Système Acoustique Remorqué) high‐resolution, deep‐towed sidescan sonar and sub‐bottom profiler. The data are augmented by seismic reflection profiles, cores and observations from submersibles. Failure occurs only in water depths greater than about 650 m. Rotational, retrogressive slumps, on a variety of scales, appear to have been initiated on local steep areas of seabed above shallow (5–25 m) regional shear planes covering a large area of the failure zone. The slumps pass downslope into debris flows, which include blocky lemniscate bodies and intervening channels. Clear evidence of current erosion is found only in steep‐sided valleys: we infer that debris flows passed through hydraulic jumps on these steep slopes and were transformed into turbidity currents which then evolved ignitively. Delayed retrogressive failure and transformation of debris flows into turbidity currents through hydraulic jumps provide a mechanism to produce a turbidity current with sustained flow over many hours.

@article{doi101046j13653091199900204x,
    author = "Piper, David J. W. and Cochonat, P. and Morrison, Martin L.",
    title = "The sequence of events around the epicentre of the 1929 Grand Banks earthquake: initiation of debris flows and turbidity current inferred from sidescan sonar",
    year = "1999",
    journal = "Sedimentology",
    abstract = "Continental slope sediment failures around the epicentre of the 1929 ‘Grand Banks’ earthquake have been imaged with the SAR (Système Acoustique Remorqué) high‐resolution, deep‐towed sidescan sonar and sub‐bottom profiler. The data are augmented by seismic reflection profiles, cores and observations from submersibles. Failure occurs only in water depths greater than about 650 m. Rotational, retrogressive slumps, on a variety of scales, appear to have been initiated on local steep areas of seabed above shallow (5–25 m) regional shear planes covering a large area of the failure zone. The slumps pass downslope into debris flows, which include blocky lemniscate bodies and intervening channels. Clear evidence of current erosion is found only in steep‐sided valleys: we infer that debris flows passed through hydraulic jumps on these steep slopes and were transformed into turbidity currents which then evolved ignitively. Delayed retrogressive failure and transformation of debris flows into turbidity currents through hydraulic jumps provide a mechanism to produce a turbidity current with sustained flow over many hours.",
    url = "https://doi.org/10.1046/j.1365-3091.1999.00204.x",
    doi = "10.1046/j.1365-3091.1999.00204.x",
    openalex = "W2063261374"
}

Abstract A Geographic Information System (GIS) database incorporating information from 241 publications, theses, and dissertations; well logs and paleontologic reports; and interpreted University of Texas Institute for Geophysics (UTIG) deep-basin seismic lines was used to map and interpret 18 basinwide genetic stratigraphic sequences that form the Gulf of Mexico basin Cenozoic fill. Eight principal extrabasinal fluvial axes provided the bulk of the sediment infill in the basin. First-order temporal and spatial use of these axes reflects four continent-scale phases of crustal uplift. Abundant sediment supply has prograded the northern and northwestern basin margin 150 to 180 mi (240 to 290 km) from its inherited Cretaceous position. Margin outbuilding has been locally and briefly interrupted by hypersubsidence due to salt withdrawal and mass wasting. Three depositional systems tracts characterize Cenozoic genetic sequences: (1) fluvial -> delta -> delta-fed apron, (2) coastal plain -> shore zone -> shelf -> shelf-fed apron, and (3) delta flank -> submarine fan. One or more examples of the fluvial -> delta -> delta-fed apron systems tract occur in each of the major genetic sequences. Immense volumes of sand have bypassed the shelf margin to be deposited in slope and base-of-slope systems, primarily within fluvial -> delta -> delta-fed apron system tracts, during all major Paleogene and Neogene depositional episodes. Deposition and preservation of volumetrically significant coastal plain -> shore zone -> shelf -> shelf-fed apron tracts is typical of Paleogene through Miocene depositional episodes only. Fan system origin was commonly associated with major continental margin failures, but large submarine canyons occur mainly in Pleistocene sequences. Thick, potential reservoir sand bodies occur in offlapping delta-fed slope and subjacent basin floor aprons, in autochthonous slope aprons and related infills of slide scars and canyon cuts, and in submarine fans.

@article{doi1013068626c37f173b11d78645000102c1865d,
    author = "Galloway, William E. and Ganey-Curry, Patricia and Li, Xiang and Buffler, Richard T.",
    title = "Cenozoic Depositional History of the Gulf of Mexico Basin",
    year = "2000",
    journal = "AAPG Bulletin",
    abstract = "Abstract A Geographic Information System (GIS) database incorporating information from 241 publications, theses, and dissertations; well logs and paleontologic reports; and interpreted University of Texas Institute for Geophysics (UTIG) deep-basin seismic lines was used to map and interpret 18 basinwide genetic stratigraphic sequences that form the Gulf of Mexico basin Cenozoic fill. Eight principal extrabasinal fluvial axes provided the bulk of the sediment infill in the basin. First-order temporal and spatial use of these axes reflects four continent-scale phases of crustal uplift. Abundant sediment supply has prograded the northern and northwestern basin margin 150 to 180 mi (240 to 290 km) from its inherited Cretaceous position. Margin outbuilding has been locally and briefly interrupted by hypersubsidence due to salt withdrawal and mass wasting. Three depositional systems tracts characterize Cenozoic genetic sequences: (1) fluvial -\> delta -\> delta-fed apron, (2) coastal plain -\> shore zone -\> shelf -\> shelf-fed apron, and (3) delta flank -\> submarine fan. One or more examples of the fluvial -\> delta -\> delta-fed apron systems tract occur in each of the major genetic sequences. Immense volumes of sand have bypassed the shelf margin to be deposited in slope and base-of-slope systems, primarily within fluvial -\> delta -\> delta-fed apron system tracts, during all major Paleogene and Neogene depositional episodes. Deposition and preservation of volumetrically significant coastal plain -\> shore zone -\> shelf -\> shelf-fed apron tracts is typical of Paleogene through Miocene depositional episodes only. Fan system origin was commonly associated with major continental margin failures, but large submarine canyons occur mainly in Pleistocene sequences. Thick, potential reservoir sand bodies occur in offlapping delta-fed slope and subjacent basin floor aprons, in autochthonous slope aprons and related infills of slide scars and canyon cuts, and in submarine fans.",
    url = "https://doi.org/10.1306/8626c37f-173b-11d7-8645000102c1865d",
    doi = "10.1306/8626c37f-173b-11d7-8645000102c1865d",
    openalex = "W2105082865",
    references = "caughey1981deltaic, doi10100797814684827687, doi1010079783642610189, doi1010160025322771900533, doi101086629710, doi1011300091761319930210483nagmhf23co2, doi101130dnaggnaj245, doi1013060c9b2321171011d78645000102c1865d, doi1013061d9bc5bb172d11d78645000102c1865d, doi1013061d9bc5d9172d11d78645000102c1865d, doi101306703c9afa170711d78645000102c1865d, doi101306bdff8876171811d78645000102c1865d, doi101306bdff8f88171811d78645000102c1865d, doi102110pec95040129, doi105724gcs84050109, openalexw1599441881"
}

The Ross Sandstone Formation is a 380m thick sand-rich turbidite system deposited in an intracratonic basin during a period of ca. 500,000 years. In overall terms, the system has a net aggradational/progradational trend, but this trend has been interrupted repeatedly by glacially-forced fluctuations in sea level that produced a series of condensed sections and interpreted sequence boundaries. Sheet-like turbidites, turbidite channels, megaflute surfaces, mudstone-filled gullies, and slides/slumps are recognised in the turbidite system. Channels dominate the mid to upper parts of the system and show considerable variability. The most widely developed type is a sandstone-dominated channel which comprises...

@incollection{doi105724gcs00150342,
    author = "Elliott, T.",
    title = "Depositional Architecture of a Sand-Rich, Channelized Turbidite System: The Upper Carboniferous Ross Sandstone Formation, Western Ireland",
    year = "2000",
    booktitle = "SOCIETY OF ECONOMIC PALEONTOLOGISTS AND MINERALOGISTS eBooks",
    abstract = "The Ross Sandstone Formation is a 380m thick sand-rich turbidite system deposited in an intracratonic basin during a period of ca. 500,000 years. In overall terms, the system has a net aggradational/progradational trend, but this trend has been interrupted repeatedly by glacially-forced fluctuations in sea level that produced a series of condensed sections and interpreted sequence boundaries. Sheet-like turbidites, turbidite channels, megaflute surfaces, mudstone-filled gullies, and slides/slumps are recognised in the turbidite system. Channels dominate the mid to upper parts of the system and show considerable variability. The most widely developed type is a sandstone-dominated channel which comprises...",
    url = "https://doi.org/10.5724/gcs.00.15.0342",
    doi = "10.5724/gcs.00.15.0342",
    openalex = "W2502437756"
}

Abstract The Nile Delta offshore is rapidly emerging as a major gas province. High-quality three-dimensional (3-D) seismic data, coupled with data from 13 consecutive successful deep-water exploration and appraisal wells, have highlighted clear phases of erosion and deposition within the upper Pliocene deep-marine slope channels. The gross reservoir architecture is spectacularly imaged by 3-D seismic techniques, both in time sections and through a variety of amplitude extractions, while an extensive program of core and wire-line log acquisition and analysis has enabled high-resolution definition of the channel-fill sediments. The channels were initiated by the introduction of coarse sediments to the shelf edge possibly at times of relative sea level fall. Initially, there was significant erosion, especially in areas up depositional dip, creating what we term “slope valleys”. Subsequent valley infill commonly commenced with debris flows, slumps, and slides, sometimes overlying basal, bypass-related sands, and progressed to amalgamated or stacked channels in packages of upward-decreasing net-to-gross sand ratios. This pattern was commonly repeated following reincision, which may have occurred several times. The different stages of channel development can be considered in terms of slope equilibrium with a reduction in slope gradient promoted by increases in flow size and density and decreases in grain size.

@article{doi1013061105021094,
    author = "Samuel, Andy and Kneller, Ben and Raslan, Samir and Sharp, A. and Parsons, Cormac",
    title = "Prolific deep-marine slope channels of the Nile Delta, Egypt",
    year = "2003",
    journal = "AAPG Bulletin",
    abstract = "Abstract The Nile Delta offshore is rapidly emerging as a major gas province. High-quality three-dimensional (3-D) seismic data, coupled with data from 13 consecutive successful deep-water exploration and appraisal wells, have highlighted clear phases of erosion and deposition within the upper Pliocene deep-marine slope channels. The gross reservoir architecture is spectacularly imaged by 3-D seismic techniques, both in time sections and through a variety of amplitude extractions, while an extensive program of core and wire-line log acquisition and analysis has enabled high-resolution definition of the channel-fill sediments. The channels were initiated by the introduction of coarse sediments to the shelf edge possibly at times of relative sea level fall. Initially, there was significant erosion, especially in areas up depositional dip, creating what we term “slope valleys”. Subsequent valley infill commonly commenced with debris flows, slumps, and slides, sometimes overlying basal, bypass-related sands, and progressed to amalgamated or stacked channels in packages of upward-decreasing net-to-gross sand ratios. This pattern was commonly repeated following reincision, which may have occurred several times. The different stages of channel development can be considered in terms of slope equilibrium with a reduction in slope gradient promoted by increases in flow size and density and decreases in grain size.",
    url = "https://doi.org/10.1306/1105021094",
    doi = "10.1306/1105021094",
    openalex = "W2148169148",
    references = "doi10108000206817809471524, doi1013062dc4091c0e4711d78643000102c1865d"
}

Analyses of 3-D seismic data in predominantly basin-floor settings offshore Indonesia, Nigeria, and the Gulf of Mexico, reveal the extensive presence of gravity-flow depositional elements. Five key elements were observed: (1) turbidity-flow leveed channels, (2) channel-overbank sediment waves and levees, (3) frontal splays or distributary-channel complexes, (4) crevasse-splay complexes, and (5) debris-flow channels, lobes, and sheets. Each depositional element displays a unique morphology and seismic expression. The reservoir architecture of each of these depositional elements is a function of the interaction between sedimentary process, sea-floor morphology, and sediment grain-size distribution. (1) Turbidity-flow leveed-channel widths range from greater than 3 km to less than 200 m. Sinuosity ranges from moderate to high, and channel meanders in most instances migrate down-system. The high-amplitude reflection character that commonly characterizes these features suggests the presence of sand within the channels. In some instances, high-sinuosity channels are associated with (2) channel-overbank sediment-wave development in proximal overbank levee settings, especially in association with outer channel bends. These sediment waves reach heights of 20 m and spacings of 2-3 km. The crests of these sediment waves are oriented normal to the inferred transport direction of turbidity flows, and the waves have migrated in an up-flow direction. Channel-margin levee thickness decreases systematically down-system. Where levee thickness can no longer be resolved seismically, high-sinuosity channels feed (3) frontal splays or low-sinuosity, distributary-channel complexes. Low-sinuosity distributary-channel complexes are expressed as lobate sheets up to 5-10 km wide and tens of kilometers long that extend to the distal edges of these systems. They likely comprise sheet-like sandstone units consisting of shallow channelized and associated sand-rich overbank deposits. Also observed are (4) crevasse-splay deposits, which form as a result of the breaching of levees, commonly at channel bends. Similar to frontal splays, but smaller in size, these deposits commonly are characterized by sheet-like turbidites. (5) Debris-flow deposits comprise low-sinuosity channel fills, narrow elongate lobes, and sheets and are characterized seismically by contorted, chaotic, low-amplitude reflection patterns. These deposits commonly overlie striated or grooved pavements that can be up to tens of kilometers long, 15 m deep, and 25 m wide. Where flows are unconfined, striation patterns suggest that divergent flow is common. Debris-flow deposits extend as far basinward as turbidites, and individual debris-flow units can reach 80 m in thickness and commonly are marked by steep edges. Transparent to chaotic seismic reflection character suggest that these deposits are mud-rich. Stratigraphically, deep-water basin-floor successions commonly are characterized by mass-transport deposits at the base, overlain by turbidite frontal-splay deposits and subsequently by leveed-channel deposits. Capping this succession is another mass-transport unit ultimately overlain and draped by condensed-section deposits. This succession can be related to a cycle of relative sea-level change and associated events at the corresponding shelf edge. Commonly, deposition of a deep-water sequence is initiated with the onset of relative sea-level fall and ends with subsequent rapid relative sea-level rise.

@article{doi101306111302730367,
    author = "Posamentier, Henry W. and Kolla, V.",
    title = "Seismic Geomorphology and Stratigraphy of Depositional Elements in Deep-Water Settings",
    year = "2003",
    journal = "Journal of Sedimentary Research",
    abstract = "Analyses of 3-D seismic data in predominantly basin-floor settings offshore Indonesia, Nigeria, and the Gulf of Mexico, reveal the extensive presence of gravity-flow depositional elements. Five key elements were observed: (1) turbidity-flow leveed channels, (2) channel-overbank sediment waves and levees, (3) frontal splays or distributary-channel complexes, (4) crevasse-splay complexes, and (5) debris-flow channels, lobes, and sheets. Each depositional element displays a unique morphology and seismic expression. The reservoir architecture of each of these depositional elements is a function of the interaction between sedimentary process, sea-floor morphology, and sediment grain-size distribution. (1) Turbidity-flow leveed-channel widths range from greater than 3 km to less than 200 m. Sinuosity ranges from moderate to high, and channel meanders in most instances migrate down-system. The high-amplitude reflection character that commonly characterizes these features suggests the presence of sand within the channels. In some instances, high-sinuosity channels are associated with (2) channel-overbank sediment-wave development in proximal overbank levee settings, especially in association with outer channel bends. These sediment waves reach heights of 20 m and spacings of 2-3 km. The crests of these sediment waves are oriented normal to the inferred transport direction of turbidity flows, and the waves have migrated in an up-flow direction. Channel-margin levee thickness decreases systematically down-system. Where levee thickness can no longer be resolved seismically, high-sinuosity channels feed (3) frontal splays or low-sinuosity, distributary-channel complexes. Low-sinuosity distributary-channel complexes are expressed as lobate sheets up to 5-10 km wide and tens of kilometers long that extend to the distal edges of these systems. They likely comprise sheet-like sandstone units consisting of shallow channelized and associated sand-rich overbank deposits. Also observed are (4) crevasse-splay deposits, which form as a result of the breaching of levees, commonly at channel bends. Similar to frontal splays, but smaller in size, these deposits commonly are characterized by sheet-like turbidites. (5) Debris-flow deposits comprise low-sinuosity channel fills, narrow elongate lobes, and sheets and are characterized seismically by contorted, chaotic, low-amplitude reflection patterns. These deposits commonly overlie striated or grooved pavements that can be up to tens of kilometers long, 15 m deep, and 25 m wide. Where flows are unconfined, striation patterns suggest that divergent flow is common. Debris-flow deposits extend as far basinward as turbidites, and individual debris-flow units can reach 80 m in thickness and commonly are marked by steep edges. Transparent to chaotic seismic reflection character suggest that these deposits are mud-rich. Stratigraphically, deep-water basin-floor successions commonly are characterized by mass-transport deposits at the base, overlain by turbidite frontal-splay deposits and subsequently by leveed-channel deposits. Capping this succession is another mass-transport unit ultimately overlain and draped by condensed-section deposits. This succession can be related to a cycle of relative sea-level change and associated events at the corresponding shelf edge. Commonly, deposition of a deep-water sequence is initiated with the onset of relative sea-level fall and ends with subsequent rapid relative sea-level rise.",
    url = "https://doi.org/10.1306/111302730367",
    doi = "10.1306/111302730367",
    openalex = "W1483157968",
    references = "doi101007978146848276818, doi10100797814684827684, doi101086629747, doi101086648221, doi101111j136530911983tb00702x, doi1013061d9bc5d9172d11d78645000102c1865d, doi1013062dc4091c0e4711d78643000102c1865d, doi1013062f9182e316ce11d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, doi101306a25fe3bf171b11d78645000102c1865d, doi101306m26490c5, doi102110csp9907, doi105724gcs00150782, nardin1979a, normark1978fan, openalexw1570283708, openalexw3120543430, openalexw362631153"
}

Abstract Oligocene–Miocene deep-water deposits of the Puchkirchen and basal Hall formations contain the main gas reservoirs of the Austrian Molasse Basin. A new seismostratigraphic model, based on a 2000-km2 (772-mi2), regional, three-dimensional (3-D) seismic data set, has fundamentally changed our understanding of the depositional processes and reservoir distribution in this classic deep-water foreland basin. Regional 3-D seismic attribute maps, calibrated by nearly 350 wells, reveal that sedimentation occurred primarily within the confines of a large (3–5 km [1.8–3.1 mi] wide by >100 km [>62 mi] long), low-sinuosity channel belt that occupied the Molasse Basin foredeep. The channel fill consists predominantly of turbiditic conglomerate and sandstone, as well as chaotic slump and debris-flow deposits. Overbank areas are characterized by fine-grained turbiditic sandstone and mudstone. Incised canyons and ponded slope fans were active along the southern basin margin; lateral tributary channels intersected the axial channel belt in the north. Significant accumulations of gas are stratigraphically and structurally trapped in channel thalweg and slope-fan sandstones, with more modest amounts in overbank lobe and tributary-channel deposits. Basin geometry had a profound effect on the architecture of the channel belt and subsequent sediment distribution. Large-scale deep-water channel systems are poorly documented from foreland basins; the depositional model developed for the Puchkirchen Formation was made possible through the use of high-quality seismic data and an extensive drill-core database. The depositional model may be a useful analog for other elongate, deep-water basins, especially those that lack extensive, modern data sets.

@article{doi10130610210505018,
    author = "de Ruig, Menno J. and Hubbard, Stephen M.",
    title = "Seismic facies and reservoir characteristics of a deep-marine channel belt in the Molasse foreland basin, Puchkirchen Formation, Austria",
    year = "2006",
    journal = "AAPG Bulletin",
    abstract = "Abstract Oligocene–Miocene deep-water deposits of the Puchkirchen and basal Hall formations contain the main gas reservoirs of the Austrian Molasse Basin. A new seismostratigraphic model, based on a 2000-km2 (772-mi2), regional, three-dimensional (3-D) seismic data set, has fundamentally changed our understanding of the depositional processes and reservoir distribution in this classic deep-water foreland basin. Regional 3-D seismic attribute maps, calibrated by nearly 350 wells, reveal that sedimentation occurred primarily within the confines of a large (3–5 km [1.8–3.1 mi] wide by \>100 km [\>62 mi] long), low-sinuosity channel belt that occupied the Molasse Basin foredeep. The channel fill consists predominantly of turbiditic conglomerate and sandstone, as well as chaotic slump and debris-flow deposits. Overbank areas are characterized by fine-grained turbiditic sandstone and mudstone. Incised canyons and ponded slope fans were active along the southern basin margin; lateral tributary channels intersected the axial channel belt in the north. Significant accumulations of gas are stratigraphically and structurally trapped in channel thalweg and slope-fan sandstones, with more modest amounts in overbank lobe and tributary-channel deposits. Basin geometry had a profound effect on the architecture of the channel belt and subsequent sediment distribution. Large-scale deep-water channel systems are poorly documented from foreland basins; the depositional model developed for the Puchkirchen Formation was made possible through the use of high-quality seismic data and an extensive drill-core database. The depositional model may be a useful analog for other elongate, deep-water basins, especially those that lack extensive, modern data sets.",
    url = "https://doi.org/10.1306/10210505018",
    doi = "10.1306/10210505018",
    openalex = "W2144432096",
    references = "doi101016jmarpetgeo200301004, doi101016jmarpetgeo200308003, doi101016jmarpetgeo200309001, doi101016s0264817202000090, doi101306111302730367, doi1013061d9bc5d9172d11d78645000102c1865d, doi101306212f7f312b2411d78648000102c1865d, doi1013062dc4091c0e4711d78643000102c1865d, openalexw2989049194, openalexw62718268"
}

Abstract Using modern and ancient examples we show that river-dominated deltas formed in shallow basins have multiple coeval terminal distributary channels at different scales. Sediment dispersion through multiple terminal distributary channels results in an overall lobate shape of the river-dominated delta that is opposite to the digitate Mississippi type, but similar with deltas described as wave-dominated. The examples of deltas that we present show typical coarsening-upward delta-front facies successions but do not contain deep distributary channels, as have been routinely interpreted in many ancient deltas. We show that shallow-water river-dominated delta-front deposits are typically capped by small terminal distributary channels, the cross-sectional area of which represents a small fraction of the main fluvial trunk channel. Recognizing terminal distributary channels is critical in interpretation of river-dominated deltas. Terminal distributary channels are the most distal channelized features and can be both subaerial and subaqueous. Their dimensions vary between tens of meters to kilometers in width, with common values of 100–400 m and depths of 1–3 m, and are rarely incised. The orientation of the terminal distributary channels for the same system has a large variation, with values between 123° (Volga Delta) and 248° (Lena Delta). Terminal distributary channels are intimately associated with mouth-bar deposits and are infilled by aggradation and lateral or upstream migration of the mouth bars. Deposits of terminal distributary channels have characteristic sedimentary structures of unidirectional effluent flow but also show evidence of reworking by waves and tides.

@article{doi102110jsr2006026,
    author = "Olariu, Cornel and Bhattacharya, Janok P.",
    title = "Terminal Distributary Channels and Delta Front Architecture of River-Dominated Delta Systems",
    year = "2006",
    journal = "Journal of Sedimentary Research",
    abstract = "Abstract Using modern and ancient examples we show that river-dominated deltas formed in shallow basins have multiple coeval terminal distributary channels at different scales. Sediment dispersion through multiple terminal distributary channels results in an overall lobate shape of the river-dominated delta that is opposite to the digitate Mississippi type, but similar with deltas described as wave-dominated. The examples of deltas that we present show typical coarsening-upward delta-front facies successions but do not contain deep distributary channels, as have been routinely interpreted in many ancient deltas. We show that shallow-water river-dominated delta-front deposits are typically capped by small terminal distributary channels, the cross-sectional area of which represents a small fraction of the main fluvial trunk channel. Recognizing terminal distributary channels is critical in interpretation of river-dominated deltas. Terminal distributary channels are the most distal channelized features and can be both subaerial and subaqueous. Their dimensions vary between tens of meters to kilometers in width, with common values of 100–400 m and depths of 1–3 m, and are rarely incised. The orientation of the terminal distributary channels for the same system has a large variation, with values between 123° (Volga Delta) and 248° (Lena Delta). Terminal distributary channels are intimately associated with mouth-bar deposits and are infilled by aggradation and lateral or upstream migration of the mouth bars. Deposits of terminal distributary channels have characteristic sedimentary structures of unidirectional effluent flow but also show evidence of reworking by waves and tides.",
    url = "https://doi.org/10.2110/jsr.2006.026",
    doi = "10.2110/jsr.2006.026",
    openalex = "W2132272817",
    references = "doi101306111302730367, doi1013065ceadd7616bb11d78645000102c1865d, openalexw101633874, openalexw1558464430, openalexw1592594904"
}

@article{covault2007highstand,
    author = "Covault, Jacob A. and Normark, William R. and Romans, Brian W. and Graham, Stephan A.",
    title = "Highstand fans in the California borderland: The overlooked deep-water depositional systems",
    year = "2007",
    journal = "Geology",
    url = "https://doi.org/10.1130/g23800a.1",
    doi = "10.1130/g23800a.1",
    number = "9",
    openalex = "W2084064600",
    pages = "783",
    volume = "35",
    references = "doi10100797814684827686, doi101016jquascirev200403006, doi101016s0025322702006771, doi10112111908210, doi101126science1059549, doi101130g225051, doi1013065d25c61516c111d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, doi101306bc743d7f16be11d78645000102c1865d, doi101306m26490c6"
}

Abstract The Mississippian Barnett Formation of the Fort Worth Basin is a classic shale-gas system in which the rock is the source, reservoir, and seal. Barnett strata were deposited in a deeper water foreland basin that had poor circulation with the open ocean. For most of the basin's history, bottom waters were euxinic, preserving organic matter and, thus, creating a rich source rock, along with abundant framboidal pyrite. The Barnett interval comprises a variety of facies but is dominated by fine-grained (clay- to silt-size) particles. Three general lithofacies are recognized on the basis of mineralogy, fabric, biota, and texture: (1) laminated siliceous mudstone; (2) laminated argillaceous lime mudstone (marl); and (3) skeletal, argillaceous lime packstone. Each facies contains abundant pyrite and phosphate (apatite), which are especially common at hardgrounds. Carbonate concretions, a product of early diagenesis, are also common. The entire Barnett biota is composed of debris transported to the basin from the shelf or upper oxygenated slope by hemipelagic mud plumes, dilute turbidites, and debris flows. Biogenic sediment was also sourced from the shallower, better oxygenated water column. Barnett deposition is estimated to have occurred over a 25-m.y. period, and despite the variations in sublithofacies, sedimentation style remained remarkably similar throughout this span of time.

@article{doi10130611020606059,
    author = "Loucks, Robert G. and Ruppel, Stephen C.",
    title = "Mississippian Barnett Shale: Lithofacies and depositional setting of a deep-water shale-gas succession in the Fort Worth Basin, Texas",
    year = "2007",
    journal = "AAPG Bulletin",
    abstract = "Abstract The Mississippian Barnett Formation of the Fort Worth Basin is a classic shale-gas system in which the rock is the source, reservoir, and seal. Barnett strata were deposited in a deeper water foreland basin that had poor circulation with the open ocean. For most of the basin's history, bottom waters were euxinic, preserving organic matter and, thus, creating a rich source rock, along with abundant framboidal pyrite. The Barnett interval comprises a variety of facies but is dominated by fine-grained (clay- to silt-size) particles. Three general lithofacies are recognized on the basis of mineralogy, fabric, biota, and texture: (1) laminated siliceous mudstone; (2) laminated argillaceous lime mudstone (marl); and (3) skeletal, argillaceous lime packstone. Each facies contains abundant pyrite and phosphate (apatite), which are especially common at hardgrounds. Carbonate concretions, a product of early diagenesis, are also common. The entire Barnett biota is composed of debris transported to the basin from the shelf or upper oxygenated slope by hemipelagic mud plumes, dilute turbidites, and debris flows. Biogenic sediment was also sourced from the shallower, better oxygenated water column. Barnett deposition is estimated to have occurred over a 25-m.y. period, and despite the variations in sublithofacies, sedimentation style remained remarkably similar throughout this span of time.",
    url = "https://doi.org/10.1306/11020606059",
    doi = "10.1306/11020606059",
    openalex = "W2166476646",
    references = "doi1010160016703796002098, doi101038142234b0, doi101046j13653091200100360x, doi1013065ceadd7616bb11d78645000102c1865d"
}

ABSTRACT The study of source‐to‐sink systems relates long‐term variations in sediment flux to morphogenic evolution of erosional–depositional systems. These variations are caused by an intricate combination of autogenic and allogenic forcing mechanisms that operate on multiple time scales – from individual transport events to large‐scale filling of basins. In order to achieve a better understanding of how these mechanisms influence morphological characteristics on different scales, 29 submodern source‐to‐sink systems have been investigated. The study is based on measurements of morphological parameters from catchments, shelves and slopes derived from a ∼1 km global digital elevation model dataset, in combination with data on basin floor fans, sediment supply, water discharge and deposition rates derived from published literature. By comparing various morphological and sedimentological parameters within and between individual systems, a number of relationships governing system evolution and behaviour are identified. The results suggest that the amount of low‐gradient floodplain area and river channel gradient are good indicators for catchment storage potential. Catchment area and river channel length is also related to shelf area and shelf width, respectively. Similarly to the floodplain area, these parameters are important for long‐term storage of sediment on the shelf platform. Additionally, the basin floor fan area is correlative to the long‐term deposition rate and the slope length. The slope length thus proves to be a useful parameter linking proximal and distal segments in source‐to‐sink systems. The relationships observed in this study provide insight into segment scale development of source‐to‐sink systems, and an understanding of these relationships in modern systems may result in improved knowledge on internal and external development of source‐to‐sink systems over geological time scales. They also allow for the development of a set of semi‐quantitative guidelines that can be used to predict similar relationships in other systems where data from individual system segments are missing or lacking.

@article{doi101111j13652117200900397x,
    author = "Sømme, Tor O. and Helland‐Hansen, William and Martinsen, Ole J. and Thurmond, John B.",
    title = "Relationships between morphological and sedimentological parameters in source‐to‐sink systems: a basis for predicting semi‐quantitative characteristics in subsurface systems",
    year = "2009",
    journal = "Basin Research",
    abstract = "ABSTRACT The study of source‐to‐sink systems relates long‐term variations in sediment flux to morphogenic evolution of erosional–depositional systems. These variations are caused by an intricate combination of autogenic and allogenic forcing mechanisms that operate on multiple time scales – from individual transport events to large‐scale filling of basins. In order to achieve a better understanding of how these mechanisms influence morphological characteristics on different scales, 29 submodern source‐to‐sink systems have been investigated. The study is based on measurements of morphological parameters from catchments, shelves and slopes derived from a ∼1 km global digital elevation model dataset, in combination with data on basin floor fans, sediment supply, water discharge and deposition rates derived from published literature. By comparing various morphological and sedimentological parameters within and between individual systems, a number of relationships governing system evolution and behaviour are identified. The results suggest that the amount of low‐gradient floodplain area and river channel gradient are good indicators for catchment storage potential. Catchment area and river channel length is also related to shelf area and shelf width, respectively. Similarly to the floodplain area, these parameters are important for long‐term storage of sediment on the shelf platform. Additionally, the basin floor fan area is correlative to the long‐term deposition rate and the slope length. The slope length thus proves to be a useful parameter linking proximal and distal segments in source‐to‐sink systems. The relationships observed in this study provide insight into segment scale development of source‐to‐sink systems, and an understanding of these relationships in modern systems may result in improved knowledge on internal and external development of source‐to‐sink systems over geological time scales. They also allow for the development of a set of semi‐quantitative guidelines that can be used to predict similar relationships in other systems where data from individual system segments are missing or lacking.",
    url = "https://doi.org/10.1111/j.1365-2117.2009.00397.x",
    doi = "10.1111/j.1365-2117.2009.00397.x",
    openalex = "W2038178933",
    references = "blot1982geology, covault2007highstand, doi10100797814612378841, doi10100797894009324181, doi1010160012825288900645, doi101016s0264817202000090, doi101016s0264817203000357, doi10103835073504, doi101038nature02150, doi101046j13653091200000008x, doi101086626637, doi101086628741, doi101086629606, doi101111j136530911983tb00702x, doi101126science1116412, doi1011270941294820060130, doi101130001676061952631117haaoet20co2, doi10113000167606197182563gotbdf20co2, doi1013065d25c61516c111d78645000102c1865d, doi1013065d25c96516c111d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, doi1013068626c37f173b11d78645000102c1865d, doi101306a25fe3bf171b11d78645000102c1865d, doi101306bdff8e16171811d78645000102c1865d, doi102110pec88010109"
}

Abstract Sea floor and shallow seismic data sets of terminal submarine fan lobes can provide excellent planform timeslices of distributive deep‐water systems but commonly only limited information on cross‐sectional architecture. Extensive outcrops in the Tanqua depocentre, south‐west Karoo Basin, provide these three‐dimensional constraints on lithofacies distributions, stacking patterns, depositional geometries and the stratigraphic evolution of submarine lobe deposits at a scale comparable with modern lobe systems. Detailed study (bed‐scale) of a single‐lobe complex (Fan 3) over a 15 km by 8 km area has helped to define a four‐fold hierarchy of depositional elements from bed through to lobe element, lobe and lobe complex. The Fan 3 lobe complex comprises six distinct fine‐grained sandstone packages, interpreted as lobes, which display compensational stacking patterns on a 5 km scale. Between successive lobes are thin‐bedded, very fine‐grained sandstones and siltstones that do not change lithofacies over several kilometres and therefore are identified as a different architectural element. Each lobe is built by many lobe elements, which also display compensational stacking patterns over a kilometre scale. Thickness variations of lobe elements can be extremely abrupt without erosion, particularly in distal areas where isopach maps reveal a finger‐like distal fringe to lobes. Lobe deposits, therefore, are not simple radial sheet‐dominated systems as commonly envisaged.

@article{doi101111j13653091200901073x,
    author = "Prélat, Amandine and Hodgson, David M. and Flint, Stephen S.",
    title = "Evolution, architecture and hierarchy of distributary deep‐water deposits: a high‐resolution outcrop investigation from the Permian Karoo Basin, South Africa",
    year = "2009",
    journal = "Sedimentology",
    abstract = "Abstract Sea floor and shallow seismic data sets of terminal submarine fan lobes can provide excellent planform timeslices of distributive deep‐water systems but commonly only limited information on cross‐sectional architecture. Extensive outcrops in the Tanqua depocentre, south‐west Karoo Basin, provide these three‐dimensional constraints on lithofacies distributions, stacking patterns, depositional geometries and the stratigraphic evolution of submarine lobe deposits at a scale comparable with modern lobe systems. Detailed study (bed‐scale) of a single‐lobe complex (Fan 3) over a 15 km by 8 km area has helped to define a four‐fold hierarchy of depositional elements from bed through to lobe element, lobe and lobe complex. The Fan 3 lobe complex comprises six distinct fine‐grained sandstone packages, interpreted as lobes, which display compensational stacking patterns on a 5 km scale. Between successive lobes are thin‐bedded, very fine‐grained sandstones and siltstones that do not change lithofacies over several kilometres and therefore are identified as a different architectural element. Each lobe is built by many lobe elements, which also display compensational stacking patterns over a kilometre scale. Thickness variations of lobe elements can be extremely abrupt without erosion, particularly in distal areas where isopach maps reveal a finger‐like distal fringe to lobes. Lobe deposits, therefore, are not simple radial sheet‐dominated systems as commonly envisaged.",
    url = "https://doi.org/10.1111/j.1365-3091.2009.01073.x",
    doi = "10.1111/j.1365-3091.2009.01073.x",
    openalex = "W1977385910",
    references = "doi10100797814684827684, doi10100797894009324181, doi101016s0264817299000112, doi101016s0264817299000641, doi101046j13653091200300560x, doi101111j136530911977tb00126x, doi101111j13653091200700926x, doi101306111302730367, doi101306212f7f312b2411d78648000102c1865d, doi1013062f9182e316ce11d78645000102c1865d, doi1013065d25cc7916c111d78645000102c1865d, normark1978fan, posamentier2011deepwater"
}

Abstract Climbing‐ripple cross‐lamination is most commonly deposited by turbidity currents when suspended load fallout and bedload transport occur contemporaneously. The angle of ripple climb reflects the ratio of suspended load fallout and bedload sedimentation rates, allowing for the calculation of the flow properties and durations of turbidity currents. Three areas exhibiting thick (>50 m) sections of deep‐water climbing‐ripple cross‐lamination deposits are the focus of this study: (i) the Miocene upper Mount Messenger Formation in the Taranaki Basin, New Zealand; (ii) the Permian Skoorsteenberg Formation in the Tanqua depocentre of the Karoo Basin, South Africa; and (iii) the lower Pleistocene Magnolia Field in the Titan Basin, Gulf of Mexico. Facies distributions and local contextual information indicate that climbing‐ripple cross‐lamination in each area was deposited in an ‘off‐axis’ setting where flows were expanding due to loss of confinement or a decrease in slope gradient. The resultant reduction in flow thickness, Reynolds number, shear stress and capacity promoted suspension fallout and thus climbing‐ripple cross‐lamination formation. Climbing‐ripple cross‐lamination in the New Zealand study area was deposited both outside of and within channels at an inferred break in slope, where flows were decelerating and expanding. In the South Africa study area, climbing‐ripple cross‐lamination was deposited due to a loss of flow confinement. In the Magnolia study area, an abrupt decrease in gradient near a basin sill caused flow deceleration and climbing‐ripple cross‐lamination deposition in off‐axis settings. Sedimentation rate and accumulation time were calculated for 44 climbing‐ripple cross‐lamination sedimentation units from the three areas using TDURE, a mathematical model developed by Baas et al. (2000). For T c divisions and T bc beds averaging 26 cm and 37 cm thick, respectively, average climbing‐ripple cross‐lamination and whole bed sedimentation rates were 0·15 mm sec −1 and 0·26 mm sec −1 and average accumulation times were 27 min and 35 min, respectively. In some instances, distinct stratigraphic trends of sedimentation rate give insight into the evolution of the depositional environment. Climbing‐ripple cross‐lamination in the three study areas is developed in very fine‐grained to fine‐grained sand, suggesting a grain size dependence on turbidite climbing‐ripple cross‐lamination formation. Indeed, the calculated sedimentation rates correlate well with the rate of sedimentation due to hindered settling of very fine‐grained and fine‐grained sand–water suspensions at concentrations of up to 20% and 2·5%, respectively. For coarser grains, hindered settling rates at all concentrations are much too high to form climbing‐ripple cross‐lamination, resulting in the formation of massive/structureless S 3 or T a divisions.

@article{doi101111j13653091201101283x,
    author = "Jobe, Zane and Lowe, Donald R. and Morris, William R.",
    title = "Climbing‐ripple successions in turbidite systems: depositional environments, sedimentation rates and accumulation times",
    year = "2011",
    journal = "Sedimentology",
    abstract = "Abstract Climbing‐ripple cross‐lamination is most commonly deposited by turbidity currents when suspended load fallout and bedload transport occur contemporaneously. The angle of ripple climb reflects the ratio of suspended load fallout and bedload sedimentation rates, allowing for the calculation of the flow properties and durations of turbidity currents. Three areas exhibiting thick (>50 m) sections of deep‐water climbing‐ripple cross‐lamination deposits are the focus of this study: (i) the Miocene upper Mount Messenger Formation in the Taranaki Basin, New Zealand; (ii) the Permian Skoorsteenberg Formation in the Tanqua depocentre of the Karoo Basin, South Africa; and (iii) the lower Pleistocene Magnolia Field in the Titan Basin, Gulf of Mexico. Facies distributions and local contextual information indicate that climbing‐ripple cross‐lamination in each area was deposited in an ‘off‐axis’ setting where flows were expanding due to loss of confinement or a decrease in slope gradient. The resultant reduction in flow thickness, Reynolds number, shear stress and capacity promoted suspension fallout and thus climbing‐ripple cross‐lamination formation. Climbing‐ripple cross‐lamination in the New Zealand study area was deposited both outside of and within channels at an inferred break in slope, where flows were decelerating and expanding. In the South Africa study area, climbing‐ripple cross‐lamination was deposited due to a loss of flow confinement. In the Magnolia study area, an abrupt decrease in gradient near a basin sill caused flow deceleration and climbing‐ripple cross‐lamination deposition in off‐axis settings. Sedimentation rate and accumulation time were calculated for 44 climbing‐ripple cross‐lamination sedimentation units from the three areas using TDURE, a mathematical model developed by Baas et al. (2000). For T c divisions and T bc beds averaging 26 cm and 37 cm thick, respectively, average climbing‐ripple cross‐lamination and whole bed sedimentation rates were 0·15 mm sec −1 and 0·26 mm sec −1 and average accumulation times were 27 min and 35 min, respectively. In some instances, distinct stratigraphic trends of sedimentation rate give insight into the evolution of the depositional environment. Climbing‐ripple cross‐lamination in the three study areas is developed in very fine‐grained to fine‐grained sand, suggesting a grain size dependence on turbidite climbing‐ripple cross‐lamination formation. Indeed, the calculated sedimentation rates correlate well with the rate of sedimentation due to hindered settling of very fine‐grained and fine‐grained sand–water suspensions at concentrations of up to 20\% and 2·5\%, respectively. For coarser grains, hindered settling rates at all concentrations are much too high to form climbing‐ripple cross‐lamination, resulting in the formation of massive/structureless S 3 or T a divisions.",
    url = "https://doi.org/10.1111/j.1365-3091.2011.01283.x",
    doi = "10.1111/j.1365-3091.2011.01283.x",
    openalex = "W1908834558",
    references = "doi101111j13653091200901073x, doi102110jsr2009035"
}

Abstract Submarine sediment density flows are one of the most important processes for moving sediment across our planet, yet they are extremely difficult to monitor directly. The speed of long run‐out submarine density flows has been measured directly in just five locations worldwide and their sediment concentration has never been measured directly. The only record of most density flows is their sediment deposit. This article summarizes the processes by which density flows deposit sediment and proposes a new single classification for the resulting types of deposit. Colloidal properties of fine cohesive mud ensure that mud deposition is complex, and large volumes of mud can sometimes pond or drain‐back for long distances into basinal lows. Deposition of ungraded mud (T E‐3) most probably finally results from en masse consolidation in relatively thin and dense flows, although initial size sorting of mud indicates earlier stages of dilute and expanded flow. Graded mud (T E‐2) and finely laminated mud (T E‐1) most probably result from floc settling at lower mud concentrations. Grain‐size breaks beneath mud intervals are commonplace, and record bypass of intermediate grain sizes due to colloidal mud behaviour. Planar‐laminated (T D) and ripple cross‐laminated (T C) non‐cohesive silt or fine sand is deposited by dilute flow, and the external deposit shape is consistent with previous models of spatial decelerating (dissipative) dilute flow. A grain‐size break beneath the ripple cross‐laminated (T C) interval is common, and records a period of sediment reworking (sometimes into dunes) or bypass. Finely planar‐laminated sand can be deposited by low‐amplitude bed waves in dilute flow (T B‐1), but it is most likely to be deposited mainly by high‐concentration near‐bed layers beneath high‐density flows (T B‐2). More widely spaced planar lamination (T B‐3) occurs beneath massive clean sand (T A), and is also formed by high‐density turbidity currents. High‐density turbidite deposits (T A, T B‐2 and T B‐3) have a tabular shape consistent with hindered settling, and are typically overlain by a more extensive drape of low‐density turbidite (T D and T C,). This core and drape shape suggests that events sometimes comprise two distinct flow components. Massive clean sand is less commonly deposited en masse by liquefied debris flow (D CS), in which case the clean sand is ungraded or has a patchy grain‐size texture. Clean‐sand debrites can extend for several tens of kilometres before pinching out abruptly. Up‐current transitions suggest that clean‐sand debris flows sometimes form via transformation from high‐density turbidity currents. Cohesive debris flows can deposit three types of ungraded muddy sand that may contain clasts. Thick cohesive debrites tend to occur in more proximal settings and extend from an initial slope failure. Thinner and highly mobile low‐strength cohesive debris flows produce extensive deposits restricted to distal areas. These low‐strength debris flows may contain clasts and travel long distances (D M‐2), or result from more local flow transformation due to turbulence damping by cohesive mud (D M‐1). Mapping of individual flow deposits (beds) emphasizes how a single event can contain several flow types, with transformations between flow types. Flow transformation may be from dilute to dense flow, as well as from dense to dilute flow. Flow state, deposit type and flow transformation are strongly dependent on the volume fraction of cohesive fine mud within a flow. Recent field observations show significant deviations from previous widely cited models, and many hypotheses linking flow type to deposit type are poorly tested. There is much still to learn about these remarkable flows.

@article{doi101111j13653091201201353x,
    author = "Talling, Peter J. and Masson, Douglas G. and Sumner, E. J. and Malgesini, G.",
    title = "Subaqueous sediment density flows: Depositional processes and deposit types",
    year = "2012",
    journal = "Sedimentology",
    abstract = "Abstract Submarine sediment density flows are one of the most important processes for moving sediment across our planet, yet they are extremely difficult to monitor directly. The speed of long run‐out submarine density flows has been measured directly in just five locations worldwide and their sediment concentration has never been measured directly. The only record of most density flows is their sediment deposit. This article summarizes the processes by which density flows deposit sediment and proposes a new single classification for the resulting types of deposit. Colloidal properties of fine cohesive mud ensure that mud deposition is complex, and large volumes of mud can sometimes pond or drain‐back for long distances into basinal lows. Deposition of ungraded mud (T E‐3) most probably finally results from en masse consolidation in relatively thin and dense flows, although initial size sorting of mud indicates earlier stages of dilute and expanded flow. Graded mud (T E‐2) and finely laminated mud (T E‐1) most probably result from floc settling at lower mud concentrations. Grain‐size breaks beneath mud intervals are commonplace, and record bypass of intermediate grain sizes due to colloidal mud behaviour. Planar‐laminated (T D) and ripple cross‐laminated (T C) non‐cohesive silt or fine sand is deposited by dilute flow, and the external deposit shape is consistent with previous models of spatial decelerating (dissipative) dilute flow. A grain‐size break beneath the ripple cross‐laminated (T C) interval is common, and records a period of sediment reworking (sometimes into dunes) or bypass. Finely planar‐laminated sand can be deposited by low‐amplitude bed waves in dilute flow (T B‐1), but it is most likely to be deposited mainly by high‐concentration near‐bed layers beneath high‐density flows (T B‐2). More widely spaced planar lamination (T B‐3) occurs beneath massive clean sand (T A), and is also formed by high‐density turbidity currents. High‐density turbidite deposits (T A, T B‐2 and T B‐3) have a tabular shape consistent with hindered settling, and are typically overlain by a more extensive drape of low‐density turbidite (T D and T C,). This core and drape shape suggests that events sometimes comprise two distinct flow components. Massive clean sand is less commonly deposited en masse by liquefied debris flow (D CS), in which case the clean sand is ungraded or has a patchy grain‐size texture. Clean‐sand debrites can extend for several tens of kilometres before pinching out abruptly. Up‐current transitions suggest that clean‐sand debris flows sometimes form via transformation from high‐density turbidity currents. Cohesive debris flows can deposit three types of ungraded muddy sand that may contain clasts. Thick cohesive debrites tend to occur in more proximal settings and extend from an initial slope failure. Thinner and highly mobile low‐strength cohesive debris flows produce extensive deposits restricted to distal areas. These low‐strength debris flows may contain clasts and travel long distances (D M‐2), or result from more local flow transformation due to turbulence damping by cohesive mud (D M‐1). Mapping of individual flow deposits (beds) emphasizes how a single event can contain several flow types, with transformations between flow types. Flow transformation may be from dilute to dense flow, as well as from dense to dilute flow. Flow state, deposit type and flow transformation are strongly dependent on the volume fraction of cohesive fine mud within a flow. Recent field observations show significant deviations from previous widely cited models, and many hypotheses linking flow type to deposit type are poorly tested. There is much still to learn about these remarkable flows.",
    url = "https://doi.org/10.1111/j.1365-3091.2012.01353.x",
    doi = "10.1111/j.1365-3091.2012.01353.x",
    openalex = "W1934469433",
    references = "dejong1972flysch, doi1010160012825283900223, doi1010160037073880900524, doi1010160040195171900382, doi101016jmarpetgeo200301003, doi101016jmarpetgeo200309001, doi101016jmarpetgeo200902012, doi101016s0012825297818582, doi101016s0264817299000112, doi10102900eo00168, doi10102997rg00426, doi101046j13653091200100360x, doi101086625710, doi101086629606, doi101098rspa19540186, doi101098rsta20061810, doi101098rstl18830029, doi101111j136530911976tb00051x, doi101111j136530911977tb00122x, doi101111j13653091200801019x, doi101111j13653091200901073x, doi101146annurevfluid121108145618, doi1013062f9182e316ce11d78645000102c1865d, doi10130674d7262b2b2111d78648000102c1865d, doi102110sedred200434, nardin1979a, openalexw1570283708, openalexw580680426"
}

@article{doi101016jjhydrol201405022,
    author = "Borga, Marco and Stoffel, Markus and Marchi, Lorenzo and Marra, Francesco and Jakob, Matthias",
    title = "Hydrogeomorphic response to extreme rainfall in headwater systems: Flash floods and debris flows",
    year = "2014",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/j.jhydrol.2014.05.022",
    doi = "10.1016/j.jhydrol.2014.05.022",
    openalex = "W2125830490",
    references = "doi10100797836426975939, doi101016jscitotenv201211043, doi101130g332171"
}

When we look back the contributions on submarine fans during the past 65 years (1950–2015), the empirical data on 21 modern submarine fans and 10 ancient deep-water systems, published by the results of the First COMFAN (Committee on FANs) Meeting (Bouma et al., 1985a), have remained the single most significant compilation of data on submarine fans. The 1970s were the “heyday” of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal elements of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean (Bay of Bengal), and the East Sea (Korea). The Annot Sandstone (Eocene–Oligocene), exposed at Peira-Cava area, SE France, which served as the type locality for the “Bouma Sequence”, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite-fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970–2015, are discussed using modern and ancient systems. They are: (1) the classic submarine fan model with attached lobes, (2) the detached-lobe model, (3) the channel-levee complex without lobes, (4) the delta-fed ramp model, (5) the gully-lobe model, (6) the suprafan lobe model, (7) the depositional lobe model, (8) the fan lobe model, (9) the ponded lobe model, (10) the nine models based on grain size and sediment source, (11) the four fan models based on tectonic settings, (12) the Jackfork debrite model, (13) the basin-floor fan model, (14) supercritical and subcritical fans, and (15) the three types of fan reservoirs. Each model is unique, and the long-standing belief that submarine fans are composed of turbidites, in particular, of gravelly and sandy high-density turbidites, is a myth. This is because there are no empirical data to validate the existence of gravelly and sandy high-density turbidity currents in the modern marine environments. Also, there are no experimental documentation of true turbidity currents that can transport gravels and coarse sands in turbulent suspension. Mass-transport processes, which include slides, slumps, and debris flows (but not turbidity currenrs), are the most viable mechanisms for transporting gravels and sands into the deep sea. The prevailing notion that submarine fans develop during periods of sea-level lowstands is also a myth. The geologic reality is that frequent short-term events that last for only a few minutes to several hours or days (e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.) are more important in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years (e.g., lowstand systems tract). Submarine fans are still in a stage of muddled turbidite paradigm because the concept of high-density turbidity currents is incommensurable.

@article{doi101016jjop201508011,
    author = "Shanmugam, G.",
    title = "Submarine fans: A critical retrospective (1950–2015)",
    year = "2016",
    journal = "Journal of Palaeogeography",
    abstract = "When we look back the contributions on submarine fans during the past 65 years (1950–2015), the empirical data on 21 modern submarine fans and 10 ancient deep-water systems, published by the results of the First COMFAN (Committee on FANs) Meeting (Bouma et al., 1985a), have remained the single most significant compilation of data on submarine fans. The 1970s were the “heyday” of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal elements of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean (Bay of Bengal), and the East Sea (Korea). The Annot Sandstone (Eocene–Oligocene), exposed at Peira-Cava area, SE France, which served as the type locality for the “Bouma Sequence”, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite-fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970–2015, are discussed using modern and ancient systems. They are: (1) the classic submarine fan model with attached lobes, (2) the detached-lobe model, (3) the channel-levee complex without lobes, (4) the delta-fed ramp model, (5) the gully-lobe model, (6) the suprafan lobe model, (7) the depositional lobe model, (8) the fan lobe model, (9) the ponded lobe model, (10) the nine models based on grain size and sediment source, (11) the four fan models based on tectonic settings, (12) the Jackfork debrite model, (13) the basin-floor fan model, (14) supercritical and subcritical fans, and (15) the three types of fan reservoirs. Each model is unique, and the long-standing belief that submarine fans are composed of turbidites, in particular, of gravelly and sandy high-density turbidites, is a myth. This is because there are no empirical data to validate the existence of gravelly and sandy high-density turbidity currents in the modern marine environments. Also, there are no experimental documentation of true turbidity currents that can transport gravels and coarse sands in turbulent suspension. Mass-transport processes, which include slides, slumps, and debris flows (but not turbidity currenrs), are the most viable mechanisms for transporting gravels and sands into the deep sea. The prevailing notion that submarine fans develop during periods of sea-level lowstands is also a myth. The geologic reality is that frequent short-term events that last for only a few minutes to several hours or days (e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.) are more important in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years (e.g., lowstand systems tract). Submarine fans are still in a stage of muddled turbidite paradigm because the concept of high-density turbidity currents is incommensurable.",
    url = "https://doi.org/10.1016/j.jop.2015.08.011",
    doi = "10.1016/j.jop.2015.08.011",
    openalex = "W2309593205",
    references = "behrmann2006rapid, crossref1978gulf, crossref1996the, doi1010160012825286900012, doi10102997rg00426, doi101046j144016142002t01501102ax, doi10108000288306196910420225, doi101111j13653091200700926x, doi101111j13653091200801019x, doi101130081372356655, doi101130g332171, doi101130spe65p1, doi101144gslsp19850180103, doi101306212f7f312b2411d78648000102c1865d, doi1013065ceae13616bb11d78645000102c1865d, doi1043249781912281589, doi105860choice295709, doi105860choice342173, doi105860choice444462, doi107208chicago97802264581060010001, openalexw2267844404"
}

Catchments provide water and sediment to downstream sedimentary systems, and these form individual source-to-sink systems. Source-to-sink systems comprise adjacent linked segments, commonly hinterland catchments, alluvial- and coastal plains, the continental shelf, continental slope and submarine fan. The dimensions of the catchment and how it scales to downstream segments provides insight into the sedimentary and tectonic controls that influence the morphology and sedimentation patterns in a basins evolution. In ancient sedimentary successions, where the sedimentary routing system is buried and inaccessible for study, or fragmented due to uplift and erosion, using scaling relationships can provide a powerful tool to understand the complete sedimentary system. Observational data from modern sedimentary systems provide an opportunity to create morphological and sedimentological scaling relationships of segments on the entire source-to-sink system. However, previous studies on global modern source-to-sink systems have typically been based on a limited number of examples restricted by the data available at the time and the methodology used to analyze large datasets. In the last decade, the volume and quality of remotely sensed information has significantly improved so that it is now timely to revisit scaling relationships of modern source-to-sink systems' segment morphologies, and discuss the implications of those results for sedimentological parameters and applicability to ancient source-to-sink systems. The results of this reanalysis show that dimensions of the catchment and submarine fan segments scale internally in terms of fan width, length and area. In addition, fan area scales to its largest hinterland catchment area in agreement with previous studies, however, it is important to consider all catchments that contribute sediment to a basin floor region. In paleogeographic settings, where individual submarine fans are difficult to tie to a single catchment, and where basin floor systems are amalgamated, the contributing sediment discharge of all catchments may be significant and likely influence the scale of its submarine fan. Accommodation versus sediment supply in relation to relative sea level change are important controls on the position of the shoreline which vary considerably from system to system over time and space, thus influencing morphological relationships between source-to-sink segments. The continental shelf should therefore be viewed as a transient geomorphic feature rather than a segment of a source-to-sink system. Furthermore, the continental slope length should not be used to scale other segments of the source-to-sink system, which contradicts previous research. The underlying tectonic and sedimentological control on the continental shelf and slope segments, in addition to the subjective interpretation of their basinward boundaries, may render those segments unsuitable for scaling the morphology of other segments. The study highlights both the temporal variability and complexity of controls that influence the morphology and scaling relationships of internal and adjacent linked source-to-sink segments, and the need to place this in a framework of both tectonic and sedimentological history.

@article{doi101016jsedgeo201806007,
    author = "Nyberg, Björn and Helland‐Hansen, William and Gawthorpe, Rob L. and Sandbakken, Pål and Eide, Christian Haug and Sømme, Tor O. and Hadler-Jacobsen, Frode and Leiknes, Sture",
    title = "Revisiting morphological relationships of modern source-to-sink segments as a first-order approach to scale ancient sedimentary systems",
    year = "2018",
    journal = "Sedimentary Geology",
    abstract = "Catchments provide water and sediment to downstream sedimentary systems, and these form individual source-to-sink systems. Source-to-sink systems comprise adjacent linked segments, commonly hinterland catchments, alluvial- and coastal plains, the continental shelf, continental slope and submarine fan. The dimensions of the catchment and how it scales to downstream segments provides insight into the sedimentary and tectonic controls that influence the morphology and sedimentation patterns in a basins evolution. In ancient sedimentary successions, where the sedimentary routing system is buried and inaccessible for study, or fragmented due to uplift and erosion, using scaling relationships can provide a powerful tool to understand the complete sedimentary system. Observational data from modern sedimentary systems provide an opportunity to create morphological and sedimentological scaling relationships of segments on the entire source-to-sink system. However, previous studies on global modern source-to-sink systems have typically been based on a limited number of examples restricted by the data available at the time and the methodology used to analyze large datasets. In the last decade, the volume and quality of remotely sensed information has significantly improved so that it is now timely to revisit scaling relationships of modern source-to-sink systems' segment morphologies, and discuss the implications of those results for sedimentological parameters and applicability to ancient source-to-sink systems. The results of this reanalysis show that dimensions of the catchment and submarine fan segments scale internally in terms of fan width, length and area. In addition, fan area scales to its largest hinterland catchment area in agreement with previous studies, however, it is important to consider all catchments that contribute sediment to a basin floor region. In paleogeographic settings, where individual submarine fans are difficult to tie to a single catchment, and where basin floor systems are amalgamated, the contributing sediment discharge of all catchments may be significant and likely influence the scale of its submarine fan. Accommodation versus sediment supply in relation to relative sea level change are important controls on the position of the shoreline which vary considerably from system to system over time and space, thus influencing morphological relationships between source-to-sink segments. The continental shelf should therefore be viewed as a transient geomorphic feature rather than a segment of a source-to-sink system. Furthermore, the continental slope length should not be used to scale other segments of the source-to-sink system, which contradicts previous research. The underlying tectonic and sedimentological control on the continental shelf and slope segments, in addition to the subjective interpretation of their basinward boundaries, may render those segments unsuitable for scaling the morphology of other segments. The study highlights both the temporal variability and complexity of controls that influence the morphology and scaling relationships of internal and adjacent linked source-to-sink segments, and the need to place this in a framework of both tectonic and sedimentological history.",
    url = "https://doi.org/10.1016/j.sedgeo.2018.06.007",
    doi = "10.1016/j.sedgeo.2018.06.007",
    openalex = "W2807893319",
    references = "doi101016jjop201508011, doi101017cbo9780511781247, doi1010292008eo100001, doi101046j13652117199601491x, doi101046j13652699200000489x, doi101046j13653091200000008x, doi10108001490410903297766, doi101086628741, doi101086629606, doi101130001676061952631117haaoet20co2, doi101130b310651, doi1013065d25c96516c111d78645000102c1865d, openalexw2883478268"
}

The U. S. National Aeronautics and Space Administration (NASA) has archived thousands of satellite images of density plumes in its online publishing outlet called ‘Earth Observatory’ since 1999. Although these images are in the public domain, there has not been any systematic compilation of configurations of density plumes associated with various sedimentary environments and processes. This article, based on 45 case studies covering 21 major rivers (e.g., Amazon, Betsiboka, Congo [Zaire], Copper, Hugli [Ganges], Mackenzie, Mississippi, Niger, Nile, Rhone, Rio de la Plata, Yellow, Yangtze, Zambezi, etc.) and six different depositional environments (i.e., marine, lacustrine, estuarine, lagoon, bay, and reef), is the first attempt in illustrating natural variability of configurations of density plumes in modern environments. There are, at least, 24 configurations of density plumes. An important finding of this study is that density plumes are controlled by a plethora of 18 oceanographic, meteorological, and other external factors. Examples are: 1) Yellow River in China by tidal shear front and by a change in river course; 2) Yangtze River in China by shelf currents and vertical mixing by tides in winter months; 3) Rio de la Plata Estuary in Argentina and Uruguay by Ocean currents; 4) San Francisco Bay in California by tidal currents; 5) Gulf of Manner in the Indian Ocean by monsoonal currents; 6) Egypt in Red Sea by Eolian dust; 7) U.S. Atlantic margin by cyclones; 8) Sri Lanka by tsunamis; 9) Copper River in Alaska by high-gradient braid delta; 10) Lake Erie by seiche; 11) continental margin off Namibia by upwelling; 12) Bering Sea by phytoplankton; 13) the Great Bahama Bank in the Atlantic Ocean by fish activity; 14) Indonesia by volcanic activity; 15) Greenland by glacial melt; 16) South Pacific Ocean by coral reef; 17) Carolina continental Rise by pockmarks; and 18) Otsuchi Bay in Japan by internal bore. The prevailing trend in promoting a single type of river-flood triggered hyperpycnal flow is flawed because there are 16 types of hyperpycnal flows. River-flood derived hyperpycnal flows are muddy in texture and they occur close to the shoreline in inner shelf environments. Hyperpycnal flows are not viable transport mechanisms of sand and gravel across the shelf into the deep sea. The available field observations suggest that they do not form meter-thick sand layers in deep water settings. For the above reasons, river-flood triggered hyperpycnites are considered unsuitable for serving as petroleum reservoirs in deep-water environments until proven otherwise.

@article{doi101016s1876380418300697,
    author = "Shanmugam, G.",
    title = "A global satellite survey of density plumes at river mouths and at other environments: Plume configurations, external controls, and implications for deep-water sedimentation",
    year = "2018",
    journal = "Petroleum Exploration and Development",
    abstract = "The U. S. National Aeronautics and Space Administration (NASA) has archived thousands of satellite images of density plumes in its online publishing outlet called ‘Earth Observatory’ since 1999. Although these images are in the public domain, there has not been any systematic compilation of configurations of density plumes associated with various sedimentary environments and processes. This article, based on 45 case studies covering 21 major rivers (e.g., Amazon, Betsiboka, Congo [Zaire], Copper, Hugli [Ganges], Mackenzie, Mississippi, Niger, Nile, Rhone, Rio de la Plata, Yellow, Yangtze, Zambezi, etc.) and six different depositional environments (i.e., marine, lacustrine, estuarine, lagoon, bay, and reef), is the first attempt in illustrating natural variability of configurations of density plumes in modern environments. There are, at least, 24 configurations of density plumes. An important finding of this study is that density plumes are controlled by a plethora of 18 oceanographic, meteorological, and other external factors. Examples are: 1) Yellow River in China by tidal shear front and by a change in river course; 2) Yangtze River in China by shelf currents and vertical mixing by tides in winter months; 3) Rio de la Plata Estuary in Argentina and Uruguay by Ocean currents; 4) San Francisco Bay in California by tidal currents; 5) Gulf of Manner in the Indian Ocean by monsoonal currents; 6) Egypt in Red Sea by Eolian dust; 7) U.S. Atlantic margin by cyclones; 8) Sri Lanka by tsunamis; 9) Copper River in Alaska by high-gradient braid delta; 10) Lake Erie by seiche; 11) continental margin off Namibia by upwelling; 12) Bering Sea by phytoplankton; 13) the Great Bahama Bank in the Atlantic Ocean by fish activity; 14) Indonesia by volcanic activity; 15) Greenland by glacial melt; 16) South Pacific Ocean by coral reef; 17) Carolina continental Rise by pockmarks; and 18) Otsuchi Bay in Japan by internal bore. The prevailing trend in promoting a single type of river-flood triggered hyperpycnal flow is flawed because there are 16 types of hyperpycnal flows. River-flood derived hyperpycnal flows are muddy in texture and they occur close to the shoreline in inner shelf environments. Hyperpycnal flows are not viable transport mechanisms of sand and gravel across the shelf into the deep sea. The available field observations suggest that they do not form meter-thick sand layers in deep water settings. For the above reasons, river-flood triggered hyperpycnites are considered unsuitable for serving as petroleum reservoirs in deep-water environments until proven otherwise.",
    url = "https://doi.org/10.1016/s1876-3804(18)30069-7",
    doi = "10.1016/s1876-3804(18)30069-7",
    openalex = "W2883315615",
    references = "doi101016jjop201706004"
}

An estimated 8.3 billion tonnes of non-biodegradable plastic has been produced over the last 65 years. Much of this is not recycled or disposed of ‘properly’, has a long environmental residence time and accumulates in sedimentary systems worldwide, posing a threat to important ecosystems and potentially human health. We synthesise existing knowledge of seafloor microplastic distribution, and integrate this with process-based sedimentological models of particle transport, to provide new insights, and critically, to identify future research challenges. Compilation of published data shows that microplastics pervade the global seafloor, from abyssal plains to submarine canyons and deep-sea trenches. However, few studies relate microplastic accumulation to sediment transport and deposition. Microplastics may enter directly into the sea as marine litter from shipping and fishing, or indirectly via fluvial and aeolian systems from terrestrial environments. The nature of the entry-point is critical to how terrestrially-sourced microplastics are transferred to offshore sedimentary systems. We present models for physiographic shelf connection types related to the tectono-sedimentary regime of the margin. Beyond the shelf, the principal agents for microplastic transport are: i) gravity-driven transport in sediment-laden flows; ii) settling, or conveyance through biological processes, of material that was formerly floating on the surface or suspended in the water column; iii) transport by thermohaline currents, either during settling or by reworking of deposited microplastics. We compare microplastic settling velocities to natural sediments to understand how appropriate existing sediment transport models are for explaining microplastic dispersal. Based on this analysis, and the relatively well-known behaviour or deep-marine flow types, we explore the expected distribution of microplastic particles, both in individual sedimentary event deposits and within deep-marine depositional systems. Residence time within certain deposit types and depositional environments is anticipated to be variable, which has implications for the likelihood of ingestion and incorporation into the food chain, further transport, or deeper burial. We conclude that integration of process-based sedimentological and stratigraphic knowledge with insights from modern sedimentary systems, and biological activity within them, will provide essential constraints on the transfer of microplastics to deep-marine environments, their distribution and ultimate fate, and the implications that these have for benthic ecosystems.

@article{doi103389feart201900080,
    author = "Kane, Ian and Clare, Michael",
    title = "Dispersion, Accumulation, and the Ultimate Fate of Microplastics in Deep-Marine Environments: A Review and Future Directions",
    year = "2019",
    journal = "Frontiers in Earth Science",
    abstract = "An estimated 8.3 billion tonnes of non-biodegradable plastic has been produced over the last 65 years. Much of this is not recycled or disposed of ‘properly’, has a long environmental residence time and accumulates in sedimentary systems worldwide, posing a threat to important ecosystems and potentially human health. We synthesise existing knowledge of seafloor microplastic distribution, and integrate this with process-based sedimentological models of particle transport, to provide new insights, and critically, to identify future research challenges. Compilation of published data shows that microplastics pervade the global seafloor, from abyssal plains to submarine canyons and deep-sea trenches. However, few studies relate microplastic accumulation to sediment transport and deposition. Microplastics may enter directly into the sea as marine litter from shipping and fishing, or indirectly via fluvial and aeolian systems from terrestrial environments. The nature of the entry-point is critical to how terrestrially-sourced microplastics are transferred to offshore sedimentary systems. We present models for physiographic shelf connection types related to the tectono-sedimentary regime of the margin. Beyond the shelf, the principal agents for microplastic transport are: i) gravity-driven transport in sediment-laden flows; ii) settling, or conveyance through biological processes, of material that was formerly floating on the surface or suspended in the water column; iii) transport by thermohaline currents, either during settling or by reworking of deposited microplastics. We compare microplastic settling velocities to natural sediments to understand how appropriate existing sediment transport models are for explaining microplastic dispersal. Based on this analysis, and the relatively well-known behaviour or deep-marine flow types, we explore the expected distribution of microplastic particles, both in individual sedimentary event deposits and within deep-marine depositional systems. Residence time within certain deposit types and depositional environments is anticipated to be variable, which has implications for the likelihood of ingestion and incorporation into the food chain, further transport, or deeper burial. We conclude that integration of process-based sedimentological and stratigraphic knowledge with insights from modern sedimentary systems, and biological activity within them, will provide essential constraints on the transfer of microplastics to deep-marine environments, their distribution and ultimate fate, and the implications that these have for benthic ecosystems.",
    url = "https://doi.org/10.3389/feart.2019.00080",
    doi = "10.3389/feart.2019.00080",
    openalex = "W2942579012",
    references = "doi101016jenvpol201302031, doi101016jmarpetgeo200301003, doi101016jmarpolbul201105030, doi101016jmarpolbul201109025, doi101021es201811s, doi101038ncomms15611, doi101098rstb20080205, doi101111j13653091201201353x, doi101126sciadv1700782, doi101126science1094559, doi101126science1260352, doi1013062f9182e316ce11d78645000102c1865d, doi101371journalpone0111913, nardin1979a"
}

The Late Cretaceous record offshore Argentina comprises an extensive mixed (turbidite-contourite) depositional system over 280,000 km2. This offers a key site to investigate complex assemblages of morphosedimentary features and their depositional processes during one of the major tectonic events in the southern hemisphere: the breakup of Gondwana (125 Ma) and the opening of the South Atlantic Ocean. The mixed depositional system was studied using a new 2D multichannel seismic reflection dataset and well data. This system developed along the continental slope and rise between 3500 and 6500 m SSL with nineteen 300–500 m thick, mounded drifts, separated by sixteen 2–5 km wide submarine channels. Seismic interpretation and correlations suggest four main evolutionary stages: a) the pre-drift stage (~125–89.8 Ma) from the Aptian to the Coniacian marks thermal subsidence of the margin followed by initiation of a turbidite depositional system; b) the onset stage (~89.8–81 Ma) from the Coniacian to the Campanian records the first exchange between SE turbidity flows and weak SW bottom currents; c) the growth stage (~81–66 Ma) records maximum growth from the Campanian to the Maastrichtian, characterized by the SW progradation and expansion of the mixed system due to more frequent interactions between turbidity and alongslope bottom currents; and d) the burial stage (~66 Ma) marks the cessation of the mixed system in the Paleocene due to bottom current intensification and transition to a pure contourite system, which persists until the present day. These four evolutionary phases register the Mesozoic to Cenozoic paleoceanographic fluctuations, associated with the northward opening of the South Atlantic Ocean and the establishment of a new deep-water circulation regime. Control factors for this mixed depositional system link inherited morphological structures, regional tectonic events, a mutable oceanic circulation, and recurrent gravity-driven processes. The present results were also compared with other mixed systems of similar or different geological age to contextualize the paleoceanographic and conceptual implications for deep-marine sedimentary environments. This comparison allowed us to identify two end members of drift and channel migration (upstream versus downstream), differentiated by the dominance of alongslope bottom currents vs. downslope turbidity currents. The distribution of the morphological elements and their lateral migration reflects the imprint of the most influential process and the changing energy, velocity, frequency and timing between the two processes. A future challenge will be to determine the full spectrum of mixed/hybrid systems, from turbidite-dominated to contourite-dominated settings, and how they differ vertically and spatially in the sedimentary record.

@article{doi101016jmarpetgeo2020104768,
    author = "Rodrigues, Sara and Hernández‐Molina, F. Javier and Kirby, Adam",
    title = "A Late Cretaceous mixed (turbidite-contourite) system along the Argentine Margin: Paleoceanographic and conceptual implications",
    year = "2020",
    journal = "Marine and Petroleum Geology",
    abstract = "The Late Cretaceous record offshore Argentina comprises an extensive mixed (turbidite-contourite) depositional system over 280,000 km2. This offers a key site to investigate complex assemblages of morphosedimentary features and their depositional processes during one of the major tectonic events in the southern hemisphere: the breakup of Gondwana (125 Ma) and the opening of the South Atlantic Ocean. The mixed depositional system was studied using a new 2D multichannel seismic reflection dataset and well data. This system developed along the continental slope and rise between 3500 and 6500 m SSL with nineteen 300–500 m thick, mounded drifts, separated by sixteen 2–5 km wide submarine channels. Seismic interpretation and correlations suggest four main evolutionary stages: a) the pre-drift stage (\textasciitilde 125–89.8 Ma) from the Aptian to the Coniacian marks thermal subsidence of the margin followed by initiation of a turbidite depositional system; b) the onset stage (\textasciitilde 89.8–81 Ma) from the Coniacian to the Campanian records the first exchange between SE turbidity flows and weak SW bottom currents; c) the growth stage (\textasciitilde 81–66 Ma) records maximum growth from the Campanian to the Maastrichtian, characterized by the SW progradation and expansion of the mixed system due to more frequent interactions between turbidity and alongslope bottom currents; and d) the burial stage (\textasciitilde 66 Ma) marks the cessation of the mixed system in the Paleocene due to bottom current intensification and transition to a pure contourite system, which persists until the present day. These four evolutionary phases register the Mesozoic to Cenozoic paleoceanographic fluctuations, associated with the northward opening of the South Atlantic Ocean and the establishment of a new deep-water circulation regime. Control factors for this mixed depositional system link inherited morphological structures, regional tectonic events, a mutable oceanic circulation, and recurrent gravity-driven processes. The present results were also compared with other mixed systems of similar or different geological age to contextualize the paleoceanographic and conceptual implications for deep-marine sedimentary environments. This comparison allowed us to identify two end members of drift and channel migration (upstream versus downstream), differentiated by the dominance of alongslope bottom currents vs. downslope turbidity currents. The distribution of the morphological elements and their lateral migration reflects the imprint of the most influential process and the changing energy, velocity, frequency and timing between the two processes. A future challenge will be to determine the full spectrum of mixed/hybrid systems, from turbidite-dominated to contourite-dominated settings, and how they differ vertically and spatially in the sedimentary record.",
    url = "https://doi.org/10.1016/j.marpetgeo.2020.104768",
    doi = "10.1016/j.marpetgeo.2020.104768",
    openalex = "W3093646028",
    references = "doi101016s187638041730023x"
}

Abstract Flutes and tool marks are commonly observed sedimentary structures on the bases of sandstones in deep‐water successions. These sole structures are universally used as palaeocurrent indicators but, in sharp contrast to most sedimentary structures, they are not used in palaeohydraulic reconstructions or to aid prediction of the spatial distribution of sediments. Since Kuenen's famous 1953 paper, flutes and tool marks in deep‐water systems have been linked to turbidity currents, as reflected in the standard Bouma sequence taught to generations of geologists. Yet, these structures present a series of unaddressed enigmas. Detailed field studies in the 1960s and early 1970s observed that flutes are typically associated with thicker, more proximal beds, whilst tools are generally prevalent in thinner, more distal, beds. Additionally, flutes and tool marks are rarely observed on the same surfaces, and flutes are seen to change downstream from larger wider parabolic to smaller narrower spindle‐shaped forms. No model has been proposed that explains these field‐based observations. This contribution undertakes a radical re‐examination of the formative flow conditions of flutes and tool marks, and demonstrates that they are the products of a wide range of sediment gravity flows, from turbulent flows, through transitional clay‐rich flows, to debris flows. Flutes are not solely the product of turbulent flows, but can continue to form in transitional flows. Grooves are shown to be formed by debris flows, slumps and slides, not turbidity currents, and in many cases the debris flows are linked to the debritic component of hybrid flows. Discontinuous tool marks, including skim (bounce) marks, prod marks and skip marks, are shown to be formed by transitional mud‐rich flows. Consequently, the observed spatial distribution of flutes and tool marks can be explained by a progressive increase in flow cohesivity downstream. This model of flutes and tool marks dovetails with models of hybrid flows that predict such a longitudinal increase in flow cohesivity. However, some deposits show grooves preferentially associated with Bouma T A beds, and these are likely formed by flows transforming from higher to lower cohesion, and are present in basins where hybrid beds are absent or rare. The recognition that sole structures may have no genetic link to the later overlying turbidity current deposits, and can be formed by a wide range of flow types, indicates that the existing pictorial description of the Bouma sequence is incorrect. A modified Bouma sequence is proposed here that addresses these points. In utilizing the advances in fluid dynamics since Kuenen's pioneering research, this study demonstrates that it is possible to use flutes and tool marks to interpret flow type at the point of formation, the nature of flow transformations, and the mechanics of the basal layer. These advances suggest that it is then possible to predict the nature of deposit type down‐dip. This new understanding, in combination with further testing in outcrop of the proposed relationships between sole marks and palaeohydraulics, opens up a wealth of possibilities for improving the understanding of deep‐water clastic environments, with implications for developing more complete facies models, assessing subaqueous geohazards and the resilience of seafloor infrastructure, and advancing our understanding of deep‐water sediments as archives of palaeoenvironmental change.

@article{doi101111sed12727,
    author = "Peakall, Jeff and Best, Jim and Baas, Jaco H. and Hodgson, David M. and Clare, Michael and Talling, Peter J. and Dorrell, R. M. and Lee, David R.",
    title = "An integrated process‐based model of flutes and tool marks in deep‐water environments: Implications for palaeohydraulics, the Bouma sequence and hybrid event beds",
    year = "2020",
    journal = "Sedimentology",
    abstract = "Abstract Flutes and tool marks are commonly observed sedimentary structures on the bases of sandstones in deep‐water successions. These sole structures are universally used as palaeocurrent indicators but, in sharp contrast to most sedimentary structures, they are not used in palaeohydraulic reconstructions or to aid prediction of the spatial distribution of sediments. Since Kuenen's famous 1953 paper, flutes and tool marks in deep‐water systems have been linked to turbidity currents, as reflected in the standard Bouma sequence taught to generations of geologists. Yet, these structures present a series of unaddressed enigmas. Detailed field studies in the 1960s and early 1970s observed that flutes are typically associated with thicker, more proximal beds, whilst tools are generally prevalent in thinner, more distal, beds. Additionally, flutes and tool marks are rarely observed on the same surfaces, and flutes are seen to change downstream from larger wider parabolic to smaller narrower spindle‐shaped forms. No model has been proposed that explains these field‐based observations. This contribution undertakes a radical re‐examination of the formative flow conditions of flutes and tool marks, and demonstrates that they are the products of a wide range of sediment gravity flows, from turbulent flows, through transitional clay‐rich flows, to debris flows. Flutes are not solely the product of turbulent flows, but can continue to form in transitional flows. Grooves are shown to be formed by debris flows, slumps and slides, not turbidity currents, and in many cases the debris flows are linked to the debritic component of hybrid flows. Discontinuous tool marks, including skim (bounce) marks, prod marks and skip marks, are shown to be formed by transitional mud‐rich flows. Consequently, the observed spatial distribution of flutes and tool marks can be explained by a progressive increase in flow cohesivity downstream. This model of flutes and tool marks dovetails with models of hybrid flows that predict such a longitudinal increase in flow cohesivity. However, some deposits show grooves preferentially associated with Bouma T A beds, and these are likely formed by flows transforming from higher to lower cohesion, and are present in basins where hybrid beds are absent or rare. The recognition that sole structures may have no genetic link to the later overlying turbidity current deposits, and can be formed by a wide range of flow types, indicates that the existing pictorial description of the Bouma sequence is incorrect. A modified Bouma sequence is proposed here that addresses these points. In utilizing the advances in fluid dynamics since Kuenen's pioneering research, this study demonstrates that it is possible to use flutes and tool marks to interpret flow type at the point of formation, the nature of flow transformations, and the mechanics of the basal layer. These advances suggest that it is then possible to predict the nature of deposit type down‐dip. This new understanding, in combination with further testing in outcrop of the proposed relationships between sole marks and palaeohydraulics, opens up a wealth of possibilities for improving the understanding of deep‐water clastic environments, with implications for developing more complete facies models, assessing subaqueous geohazards and the resilience of seafloor infrastructure, and advancing our understanding of deep‐water sediments as archives of palaeoenvironmental change.",
    url = "https://doi.org/10.1111/sed.12727",
    doi = "10.1111/sed.12727",
    openalex = "W3011315171",
    references = "doi101016jgeomorph201512008, doi101016jmarpetgeo201402016, doi101016jsedgeo201603008, doi101111bre12150, doi101111sed12376, doi101130b309961, doi101130ges007931"
}

@article{doi101016jearscirev2021103531,
    author = "Fisher, William L. and Galloway, William E. and Steel, Ronald J. and Olariu, Cornel and Kerans, Charles and Mohrig, David",
    title = "Deep-water depositional systems supplied by shelf-incising submarine canyons: Recognition and significance in the geologic record",
    year = "2021",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/j.earscirev.2021.103531",
    doi = "10.1016/j.earscirev.2021.103531",
    openalex = "W3124143180",
    references = "doi101016003707389290052s, doi101016jearscirev200810003, doi101016jmarpetgeo201704008, doi10102997eo00356, doi101038s41598018246306, doi1013060c9b2907171011d78645000102c1865d, doi10130610210505018, doi101306111302730367, doi1013065d25c2d316c111d78645000102c1865d, doi101306703c9af5170711d78645000102c1865d, doi101306bdff8876171811d78645000102c1865d, doi101306m26490c6, doi102110pec88010039, doi102110pec88010125, kolla1990lowstand, openalexw106150921, paine1968stratigraphy"
}

Interactions between along-slope bottom currents and down-slope turbidity flows can create a myriad of features and deposits. Despite numerous efforts to differentiate contourites from turbidites and mixed features, reliable diagnostic criteria are still lacking from the stratigraphic and sedimentological viewpoints. The main aim of this study is to develop criteria to differentiate mixed, along-slope-, and down-slope-generated elements from other deep-water deposits across bathymetric, seismic and sediment core data. Mixed (turbidite-contourite) systems can be placed in three main groups based on their location, dimensions, elongation, lateral migration, spatial and temporal variability: 1) turbidite-dominated mixed systems, 2) synchronous systems, and 3) contourite-dominated mixed systems. The persistence of bottom currents —in addition to their velocity, direction, and hydrodynamic fluctuations— is responsible for entraining and redistributing fine-grained particles, carried in suspension by coeval turbidity flows, and reworking previously deposited sediments. Changes in turbidity current velocity, frequency, and duration condition the provision of sediments and development of turbidites along mixed systems. Several preliminary models are also being proposed in this study, in order to enhance our understanding of the lateral and vertical distribution of mixed systems across the sedimentary record. Interactions between along- and down-slope processes may be synchronous, asynchronous or passive. Synchronous interactions typically occur within the same physiographic setting and the two processes interact coevally in space and time. Asynchronous interactions are also common across the modern and ancient sedimentary records, as bottom currents sweep across the deep-water environments during breaks of the turbidity flows. Passive interactions occur along the distal margins of mixed systems, or when the two processes occur near each other but do not cross over in time. Further controlling factors are held to be influential in the evolution of mixed systems at the short- to long-term; varying degrees of confinement, sediment supply or climatic fluctuations can generate cyclic stacking patterns and affect their overall dimensions. Accordingly, mixed systems feature more complex geometries than previously believed, as interactions may generate new secondary processes and features. Such systems form potential plays and may become future targets for energy geosciences and other research fields.

@article{doi101016jearscirev2022104030,
    author = "Rodrigues, Sara and Hernández-Molina, F.J. and Fonnesu, Marco and Miramontes, Elda and Rebesco, Michele and Campbell, D C",
    title = "A new classification system for mixed (turbidite-contourite) depositional systems: Examples, conceptual models and diagnostic criteria for modern and ancient records",
    year = "2022",
    journal = "Earth-Science Reviews",
    abstract = "Interactions between along-slope bottom currents and down-slope turbidity flows can create a myriad of features and deposits. Despite numerous efforts to differentiate contourites from turbidites and mixed features, reliable diagnostic criteria are still lacking from the stratigraphic and sedimentological viewpoints. The main aim of this study is to develop criteria to differentiate mixed, along-slope-, and down-slope-generated elements from other deep-water deposits across bathymetric, seismic and sediment core data. Mixed (turbidite-contourite) systems can be placed in three main groups based on their location, dimensions, elongation, lateral migration, spatial and temporal variability: 1) turbidite-dominated mixed systems, 2) synchronous systems, and 3) contourite-dominated mixed systems. The persistence of bottom currents —in addition to their velocity, direction, and hydrodynamic fluctuations— is responsible for entraining and redistributing fine-grained particles, carried in suspension by coeval turbidity flows, and reworking previously deposited sediments. Changes in turbidity current velocity, frequency, and duration condition the provision of sediments and development of turbidites along mixed systems. Several preliminary models are also being proposed in this study, in order to enhance our understanding of the lateral and vertical distribution of mixed systems across the sedimentary record. Interactions between along- and down-slope processes may be synchronous, asynchronous or passive. Synchronous interactions typically occur within the same physiographic setting and the two processes interact coevally in space and time. Asynchronous interactions are also common across the modern and ancient sedimentary records, as bottom currents sweep across the deep-water environments during breaks of the turbidity flows. Passive interactions occur along the distal margins of mixed systems, or when the two processes occur near each other but do not cross over in time. Further controlling factors are held to be influential in the evolution of mixed systems at the short- to long-term; varying degrees of confinement, sediment supply or climatic fluctuations can generate cyclic stacking patterns and affect their overall dimensions. Accordingly, mixed systems feature more complex geometries than previously believed, as interactions may generate new secondary processes and features. Such systems form potential plays and may become future targets for energy geosciences and other research fields.",
    url = "https://doi.org/10.1016/j.earscirev.2022.104030",
    doi = "10.1016/j.earscirev.2022.104030",
    openalex = "W4224871650",
    references = "doi101016jmarpetgeo201506007, doi101016jmarpetgeo201812023, doi101016s187638041730023x, doi101111sed12772, doi101130b309961, doi102110jsr202036, doi103390geosciences10020068"
}

A database-informed metastudy of 294 globally distributed submarine canyons has been conducted with the aim of elucidating the role of tectonic setting on submarine-canyon geomorphology. To achieve this, data from seafloor and subsurface studies derived from 136 peer-reviewed publications and from open-source worldwide bathymetry datasets have been statistically analyzed. In particular, relationships between margin type (active vs. passive) or plate-boundary type (convergent vs. transform vs. complex) have been assessed for key morphometric parameters of submarine canyons, including: streamwise length, maximum and average width and depth, canyon sinuosity, average canyon thalweg gradient, and maximum canyon sidewall steepness. In addition, possible scaling relationships between canyon morphometric parameters and characteristics of the associated terrestrial catchment, continental shelf and slope, and of the broader physiographic setting for canyons along both active and passive margins have been evaluated. The following principal findings arise: 1) overall canyon geomorphology is not markedly different across tectonic settings; 2) slope failure might be more important in passive-margin canyons compared to active ones, possibly due to seismic strengthening in the latter; 3) some aspects of canyon geomorphology scale with attributes of the source-to-sink system and environmental setting, but the strength and sign in scaling might differ between active and passive margins, suggesting that the extent to which canyon geomorphology can be predicted depends on the tectonic setting. Insights from our analysis augment and improve conceptual, experimental and numerical models of slope systems at the scale of individual canyons and source-to-sink systems, and increase our understanding of the complex role played by tectonic setting in shaping deep-water systems.

@article{doi103389feart2022836823,
    author = "Bührig, Laura and Colombera, Luca and Patacci, Marco and Mountney, Nigel P. and McCaffrey, William D.",
    title = "Tectonic Influence on the Geomorphology of Submarine Canyons: Implications for Deep-Water Sedimentary Systems",
    year = "2022",
    journal = "Frontiers in Earth Science",
    abstract = "A database-informed metastudy of 294 globally distributed submarine canyons has been conducted with the aim of elucidating the role of tectonic setting on submarine-canyon geomorphology. To achieve this, data from seafloor and subsurface studies derived from 136 peer-reviewed publications and from open-source worldwide bathymetry datasets have been statistically analyzed. In particular, relationships between margin type (active vs. passive) or plate-boundary type (convergent vs. transform vs. complex) have been assessed for key morphometric parameters of submarine canyons, including: streamwise length, maximum and average width and depth, canyon sinuosity, average canyon thalweg gradient, and maximum canyon sidewall steepness. In addition, possible scaling relationships between canyon morphometric parameters and characteristics of the associated terrestrial catchment, continental shelf and slope, and of the broader physiographic setting for canyons along both active and passive margins have been evaluated. The following principal findings arise: 1) overall canyon geomorphology is not markedly different across tectonic settings; 2) slope failure might be more important in passive-margin canyons compared to active ones, possibly due to seismic strengthening in the latter; 3) some aspects of canyon geomorphology scale with attributes of the source-to-sink system and environmental setting, but the strength and sign in scaling might differ between active and passive margins, suggesting that the extent to which canyon geomorphology can be predicted depends on the tectonic setting. Insights from our analysis augment and improve conceptual, experimental and numerical models of slope systems at the scale of individual canyons and source-to-sink systems, and increase our understanding of the complex role played by tectonic setting in shaping deep-water systems.",
    url = "https://doi.org/10.3389/feart.2022.836823",
    doi = "10.3389/feart.2022.836823",
    openalex = "W4281768821",
    references = "doi101016jmarpetgeo201812023, doi101016jsedgeo201806007"
}

Seismic geomorphology and stratigraphic analysis can reveal how source-to-sink systems dynamically respond to climatic and tectonic forcing. This study uses seismic reflection data from the Norwegian Sea to investigate the stratigraphic response to a short-lived (0.2 Myr) period of climate change during the Paleocene-Eocene Thermal Maximum (PETM), superimposed on a long-lived (∼8 Myr) period of hinterland uplift. The data show that long-term uplift resulted in ∼300 m of relative sea-level fall, forced regression and formation of incised valleys during the latest Paleocene-earliest Eocene. The short-lived PETM climate perturbation at ∼56 Ma changed the transport dynamics of the system, allowing sediment to be bypassed to wide channel complexes on the basin floor, feeding a large mud-rich basin-floor fan more than 50 km into the basin. Our analysis also suggest that sediment supply was up to four times higher during the PETM compared to earlier and later periods. Maximum regression at ∼55.5 Ma resulted in the formation of a subaerial unconformity. The style of subaerial incision was dictated by shelf accommodation and proximity to the area of direct sediment input. Out-of-grade shelves and slopes sourced by littoral drift were prone to incision, but direct-fed and graded shelves and slopes were not. Despite maximum regression, sediments were not transported significantly beyond the toe-of-slope aprons, suggesting that rapid climate change was more efficient in bypassing sediment to the deep-water than low stands of sea level. As long-term accommodation increased after the PETM, deltas were still able to reach shelf edge, but periods of maximum regression were not associated with deep incisions along the outer shelf and only smaller canyons and gullies formed. The shelf-slope wedge was finally transgressed at ∼51 Ma. The age of deep valley incisions overlaps with the time of subaerial erosion in the East Shetland and Faroe-Shetland basins, suggesting a common mechanism for North Atlantic uplift around 55–56 Ma. Other seismic stratigraphic surfaces do not seem to be regionally time-equivalent, highlighting the importance of local controls on internal architecture of shelf-slope wedges. This study demonstrates the high-resolution stratigraphic response to long- and short-term external forcing together with intrinsic processes and can help identify similar relationships in other areas.

@article{doi103389feart20231082203,
    author = "Sømme, Tor O. and Huwe, Simone Isabelle and Martinsen, Ole J. and Sandbakken, Pål and Skogseid, Jakob and Valore, Lucas Albanese",
    title = "Stratigraphic expression of the Paleocene-Eocene Thermal Maximum climate event during long-lived transient uplift—An example from a shallow to deep-marine clastic system in the Norwegian Sea",
    year = "2023",
    journal = "Frontiers in Earth Science",
    abstract = "Seismic geomorphology and stratigraphic analysis can reveal how source-to-sink systems dynamically respond to climatic and tectonic forcing. This study uses seismic reflection data from the Norwegian Sea to investigate the stratigraphic response to a short-lived (0.2 Myr) period of climate change during the Paleocene-Eocene Thermal Maximum (PETM), superimposed on a long-lived (∼8 Myr) period of hinterland uplift. The data show that long-term uplift resulted in ∼300 m of relative sea-level fall, forced regression and formation of incised valleys during the latest Paleocene-earliest Eocene. The short-lived PETM climate perturbation at ∼56 Ma changed the transport dynamics of the system, allowing sediment to be bypassed to wide channel complexes on the basin floor, feeding a large mud-rich basin-floor fan more than 50 km into the basin. Our analysis also suggest that sediment supply was up to four times higher during the PETM compared to earlier and later periods. Maximum regression at ∼55.5 Ma resulted in the formation of a subaerial unconformity. The style of subaerial incision was dictated by shelf accommodation and proximity to the area of direct sediment input. Out-of-grade shelves and slopes sourced by littoral drift were prone to incision, but direct-fed and graded shelves and slopes were not. Despite maximum regression, sediments were not transported significantly beyond the toe-of-slope aprons, suggesting that rapid climate change was more efficient in bypassing sediment to the deep-water than low stands of sea level. As long-term accommodation increased after the PETM, deltas were still able to reach shelf edge, but periods of maximum regression were not associated with deep incisions along the outer shelf and only smaller canyons and gullies formed. The shelf-slope wedge was finally transgressed at ∼51 Ma. The age of deep valley incisions overlaps with the time of subaerial erosion in the East Shetland and Faroe-Shetland basins, suggesting a common mechanism for North Atlantic uplift around 55–56 Ma. Other seismic stratigraphic surfaces do not seem to be regionally time-equivalent, highlighting the importance of local controls on internal architecture of shelf-slope wedges. This study demonstrates the high-resolution stratigraphic response to long- and short-term external forcing together with intrinsic processes and can help identify similar relationships in other areas.",
    url = "https://doi.org/10.3389/feart.2023.1082203",
    doi = "10.3389/feart.2023.1082203",
    openalex = "W4321377687",
    references = "doi101016jearscirev2021103531, doi101016jmarpetgeo201812023"
}

A unique synthesis of grain size-distance data is presented, comparing, for the first time, grain size and fining trends in a wide range of modern and ancient axial sediment dispersal systems, and tracking grain-size from source to sink across several sedimentary basins. In general, grain-size decreases exponentially with distance down system, and modern and ancient examples fine at broadly comparable rates in similar depositional settings. Linear fining rates vary by eight orders of magnitude, being higher in coarser-grained settings. Very few data sets have a median grain size between 1 and 5 mm in diameter, supporting the idea that material of this calibre is rare. Alluvial fans fine at the highest rates, by up to 450 cm/km (216%/km) in modern and 115 cm/km (427%/km) in ancient examples, but more typically by around 1 to 12 mm/km (87 to 1%/km), whereas fluvial gravels fine by 0.8 to 4 mm/km (0.4 to 5%/km). Sand-prone systems fine more slowly, by a few tens of microns per kilometre or less: 1 to 23 μm/km (0.25 to 2.5%/km) in distributive fluvial systems, ~1 to 8 μm/km (~1 to 6%/km) in fluvio-deltaic channels, 0.2 to 44 μm/km (0.08 to 14%/km) in ergs, and from 0.45 to 29 μm/km (0.18 to 7%/km) in basin-plain turbidites. At the basin scale, fining rates increase where gravels pinch out down-system at the fluvial gravel-sand transition, and where sands pinch out at the toe of the shoreface. Modern fluvial gravel-sand transitions are relatively well characterised, with fining rates ranging from 71 to 0.2 mm/km (483 to 2%/km), and lower rates and wider transitions in wider, longer rivers, insights that appear applicable to the rock record. Downstream fining predominantly reflects selective deposition of coarser material and preferential transport of finer grains, with subsidence increasing fining rates as coarser grains are preferentially extracted up-dip to form stratigraphy. Across short segments, grain-size can increase down system as a result of winnowing, bypass, or lateral sediment input. Comminution is largely considered a secondary factor in rivers, but important in ergs, where lateral sediment input can overwhelm downstream fining effects, and grain-size sorting across dunes may obscure longer downwind trends. In deep water, when the slope is bypassed, basin-floor fans can fine at rates comparable to contemporaneous up-dip fluvial channels, by 30 μm/km (5%/km), but if sediment is deposited on the slope, fining rates increase (225 μm/km 75%/km) as distances are shorter. Axial flow lines across basin-plain turbidites with diverse grain-size, and dimension, can be closely comparable on mass-balance plots, suggesting that the properties of one bed could inform predictions of those of another. As yet there are no studies of fining rates in conglomeratic deep-water systems, where the transition from conglomerate to sand-dominated systems is of particular interest, given its importance for fining rates in fluvial systems. The dataset has potential to constrain computer simulation models of sediment calibre, and subsurface models that address, for example, aquifer flow, and petroleum migration.

@article{doi101016jearscirev2024104699,
    author = "Reynolds, Tony",
    title = "Grain size from source to sink – modern and ancient fining rates",
    year = "2024",
    journal = "Earth-Science Reviews",
    abstract = "A unique synthesis of grain size-distance data is presented, comparing, for the first time, grain size and fining trends in a wide range of modern and ancient axial sediment dispersal systems, and tracking grain-size from source to sink across several sedimentary basins. In general, grain-size decreases exponentially with distance down system, and modern and ancient examples fine at broadly comparable rates in similar depositional settings. Linear fining rates vary by eight orders of magnitude, being higher in coarser-grained settings. Very few data sets have a median grain size between 1 and 5 mm in diameter, supporting the idea that material of this calibre is rare. Alluvial fans fine at the highest rates, by up to 450 cm/km (216\%/km) in modern and 115 cm/km (427\%/km) in ancient examples, but more typically by around 1 to 12 mm/km (87 to 1\%/km), whereas fluvial gravels fine by 0.8 to 4 mm/km (0.4 to 5\%/km). Sand-prone systems fine more slowly, by a few tens of microns per kilometre or less: 1 to 23 μm/km (0.25 to 2.5\%/km) in distributive fluvial systems, \textasciitilde 1 to 8 μm/km (\textasciitilde 1 to 6\%/km) in fluvio-deltaic channels, 0.2 to 44 μm/km (0.08 to 14\%/km) in ergs, and from 0.45 to 29 μm/km (0.18 to 7\%/km) in basin-plain turbidites. At the basin scale, fining rates increase where gravels pinch out down-system at the fluvial gravel-sand transition, and where sands pinch out at the toe of the shoreface. Modern fluvial gravel-sand transitions are relatively well characterised, with fining rates ranging from 71 to 0.2 mm/km (483 to 2\%/km), and lower rates and wider transitions in wider, longer rivers, insights that appear applicable to the rock record. Downstream fining predominantly reflects selective deposition of coarser material and preferential transport of finer grains, with subsidence increasing fining rates as coarser grains are preferentially extracted up-dip to form stratigraphy. Across short segments, grain-size can increase down system as a result of winnowing, bypass, or lateral sediment input. Comminution is largely considered a secondary factor in rivers, but important in ergs, where lateral sediment input can overwhelm downstream fining effects, and grain-size sorting across dunes may obscure longer downwind trends. In deep water, when the slope is bypassed, basin-floor fans can fine at rates comparable to contemporaneous up-dip fluvial channels, by 30 μm/km (5\%/km), but if sediment is deposited on the slope, fining rates increase (225 μm/km 75\%/km) as distances are shorter. Axial flow lines across basin-plain turbidites with diverse grain-size, and dimension, can be closely comparable on mass-balance plots, suggesting that the properties of one bed could inform predictions of those of another. As yet there are no studies of fining rates in conglomeratic deep-water systems, where the transition from conglomerate to sand-dominated systems is of particular interest, given its importance for fining rates in fluvial systems. The dataset has potential to constrain computer simulation models of sediment calibre, and subsurface models that address, for example, aquifer flow, and petroleum migration.",
    url = "https://doi.org/10.1016/j.earscirev.2024.104699",
    doi = "10.1016/j.earscirev.2024.104699",
    openalex = "W4391483031",
    references = "doi101016jearscirev2021103531"
}

The relationships between aeolian sediments in dune fields and adjacent sedimentary environments are critical for understanding arid landscapes. They provide valuable proxies for paleoclimatic reconstructions, as shown in various desert regions worldwide. Studies have highlighted how aeolian environments modulate sediment transport in fluvial systems, acting as buffers (e.g., East et al., 2015), an essential consideration for comprehensive source-to-sink sediment budgets. While research has primarily focused on fluvial-aeolian interactions, studies on alluvial fan-aeolian interactions are limited. Alluvial fans, when not bypassed, are excellent sedimentary archives for reconstructing paleoclimates in arid regions. It is known that increased aridity tends to expand aeolian coverage over fan surfaces, whereas increased runoff activity restricts aeolian environments to distal fan areas, which then serve as sediment sources for sand dune fields. However, there is a gap in understanding how fans and aeolian sediments interact when both operate simultaneously, independent of climatic variability. To address this, we studied alluvial fans in the Atacama Desert, where prolonged aridity provides a natural laboratory to explore interactions between aeolian and alluvial fan processes, with exceptional preservation of surface morphologies. Rare episodic storms generate runoff that transports sediments from catchments to alluvial fans, which may be partially or fully covered by aeolian sands. The selected fans exhibit debris flow lobes across all fan segments, not just at the apex.Our study investigates how fan morphology (e.g., roughness and relief) (Cook and Pelletier, 2007) controls saltation transport processes and pathways, and examines the interactions between dune formation and debris flow lobes. By analyzing surface grain size and topography and leveraging Synthetic Aperture Radar (SAR) backscatter intensity data from C and L Bands, calibrated with field grain size distributions and laboratory analyses, we automated the mapping of fan sediment cover. Our findings reveal that aeolian covers, including barchan dunes, do not prevent debris flows from reaching mid and distal fan areas on fans with gradients of \textasciitilde 10°. This contrasts with observations from the southwestern US fans, where star dunes can obstruct debris flow pathways (Anderson and Anderson, 1990). The interactions we have identified are relevant for improving debris flow runout modelling, interpreting past fan sedimentary arrangements, and understanding fan evolution and sediment fluxes in arid environments. These insights have broader implications for the evolution of arid landscapes, sheeding light on the dynamic interplay between aeolian and alluvial fan processes.

@misc{cabré2025interactions,
    author = "Cabré, Albert and Mather, Anne and Bufe, Aaron and Lang, Andreas",
    title = "Interactions between aeolian dune fields and debris flows in alluvial fans.",
    year = "2025",
    abstract = "The relationships between aeolian sediments in dune fields and adjacent sedimentary environments are critical for understanding arid landscapes. They provide valuable proxies for paleoclimatic reconstructions, as shown in various desert regions worldwide. Studies have highlighted how aeolian environments modulate sediment transport in fluvial systems, acting as buffers (e.g., East et al., 2015), an essential consideration for comprehensive source-to-sink sediment budgets. While research has primarily focused on fluvial-aeolian interactions, studies on alluvial fan-aeolian interactions are limited. Alluvial fans, when not bypassed, are excellent sedimentary archives for reconstructing paleoclimates in arid regions. It is known that increased aridity tends to expand aeolian coverage over fan surfaces, whereas increased runoff activity restricts aeolian environments to distal fan areas, which then serve as sediment sources for sand dune fields. However, there is a gap in understanding how fans and aeolian sediments interact when both operate simultaneously, independent of climatic variability. To address this, we studied alluvial fans in the Atacama Desert, where prolonged aridity provides a natural laboratory to explore interactions between aeolian and alluvial fan processes, with exceptional preservation of surface morphologies. Rare episodic storms generate runoff that transports sediments from catchments to alluvial fans, which may be partially or fully covered by aeolian sands. The selected fans exhibit debris flow lobes across all fan segments, not just at the apex.Our study investigates how fan morphology (e.g., roughness and relief) (Cook and Pelletier, 2007) controls saltation transport processes and pathways, and examines the interactions between dune formation and debris flow lobes. By analyzing surface grain size and topography and leveraging Synthetic Aperture Radar (SAR) backscatter intensity data from C and L Bands, calibrated with field grain size distributions and laboratory analyses, we automated the mapping of fan sediment cover. Our findings reveal that aeolian covers, including barchan dunes, do not prevent debris flows from reaching mid and distal fan areas on fans with gradients of \textasciitilde 10\&\#176;. This contrasts with observations from the southwestern US fans, where star dunes can obstruct debris flow pathways (Anderson and Anderson, 1990). The interactions we have identified are relevant for improving debris flow runout modelling, interpreting past fan sedimentary arrangements, and understanding fan evolution and sediment fluxes in arid environments. These insights have broader implications for the evolution of arid landscapes, sheeding light on the dynamic interplay between aeolian and alluvial fan processes.",
    url = "https://doi.org/10.5194/egusphere-egu25-13192",
    doi = "10.5194/egusphere-egu25-13192",
    openalex = "W4408431134"
}

Whether clay-rich shale reservoirs with low-medium maturity can serve as primary exploration targets remains a focal point of debate in the academic community. Clarifying the exploration potential of clay-rich shale reservoirs is crucial for the future exploration and development of lacustrine shale. The Triassic Yanchang Formation in the Ordos Basin has been one of most productive lacustrine shale oil systems in China, with substantial oil production capacity already established. While the primary productive layers are currently fine-grained siltstone interbeds, however, it remains a highly debated issue whether the volumetrically more significant clay-rich reservoirs can become viable exploration targets in the near future. To address this issue, we examined the exploration potential of different lithofacies assemblages in Member 7 (Mbr 7) of the Triassic Yanchang Formation, using a borehole in the Tongchuan area of the southern Ordos Basin as an example. We identified favorable exploration targets and assessed whether clay-rich reservoirs formed predominantly-freshwater conditions can become viable exploration targets. The results indicate the presence of six lithofacies in clay-rich reservoirs of Mbr 7 of the Yanchang Formation, with two main lithofacies assemblages: laminated organic-rich shale and massive mudstone. From the perspective of sandstone distribution, the sandstone interlayers within laminated organic-rich shale are primarily formed by gravity (hyperpycnal) flows, while sandstones deposited in delta front environments are typically associated with massive mudstone. Laminated organic-rich shale deposition occurred in an anoxic, deep-water environment characterized by high primary productivity, whereas massive mudstone formed in environments with high sedimentation rates and substantial terrigenous debris influx. Currently, the exploration potential of sandstone interlayers exceeds that of clay-rich reservoirs, with the greatest potential observed in the sandstone interlayers associated with laminated organic-rich shale formed by gravity (hyperpycnal) flows. Comparative analysis reveals that clay-rich reservoirs with low to medium maturity present great challenges for exploitation, making interlayer-type reservoirs the main focus of exploration at this stage. Nevertheless, clay-rich reservoirs in closed systems with high thermal maturity and organic matter content also hold considerable potential.

@article{doi101016jpetsci202506020,
    author = "Wang, Enze and Li, Maowen and Ma, Xiaoxiao and Qian, Menhui and Cao, Tingting and Li, Zhiming and Li, Sen and Jin, Zhijun",
    title = "Can clay-rich reservoirs in predominantly-freshwater lacustrine shale systems serve as primary exploration targets in low-medium maturity? A case study of the Triassic Yanchang Formation of the Ordos Basin",
    year = "2025",
    journal = "Petroleum Science",
    abstract = "Whether clay-rich shale reservoirs with low-medium maturity can serve as primary exploration targets remains a focal point of debate in the academic community. Clarifying the exploration potential of clay-rich shale reservoirs is crucial for the future exploration and development of lacustrine shale. The Triassic Yanchang Formation in the Ordos Basin has been one of most productive lacustrine shale oil systems in China, with substantial oil production capacity already established. While the primary productive layers are currently fine-grained siltstone interbeds, however, it remains a highly debated issue whether the volumetrically more significant clay-rich reservoirs can become viable exploration targets in the near future. To address this issue, we examined the exploration potential of different lithofacies assemblages in Member 7 (Mbr 7) of the Triassic Yanchang Formation, using a borehole in the Tongchuan area of the southern Ordos Basin as an example. We identified favorable exploration targets and assessed whether clay-rich reservoirs formed predominantly-freshwater conditions can become viable exploration targets. The results indicate the presence of six lithofacies in clay-rich reservoirs of Mbr 7 of the Yanchang Formation, with two main lithofacies assemblages: laminated organic-rich shale and massive mudstone. From the perspective of sandstone distribution, the sandstone interlayers within laminated organic-rich shale are primarily formed by gravity (hyperpycnal) flows, while sandstones deposited in delta front environments are typically associated with massive mudstone. Laminated organic-rich shale deposition occurred in an anoxic, deep-water environment characterized by high primary productivity, whereas massive mudstone formed in environments with high sedimentation rates and substantial terrigenous debris influx. Currently, the exploration potential of sandstone interlayers exceeds that of clay-rich reservoirs, with the greatest potential observed in the sandstone interlayers associated with laminated organic-rich shale formed by gravity (hyperpycnal) flows. Comparative analysis reveals that clay-rich reservoirs with low to medium maturity present great challenges for exploitation, making interlayer-type reservoirs the main focus of exploration at this stage. Nevertheless, clay-rich reservoirs in closed systems with high thermal maturity and organic matter content also hold considerable potential.",
    url = "https://doi.org/10.1016/j.petsci.2025.06.020",
    doi = "10.1016/j.petsci.2025.06.020",
    openalex = "W4412084999",
    references = "doi101016jsedgeo2024106629"
}