Caves

@article{yanshin1962forecasts45,
    author = "Yanshin, A. L",
    title = "Forecasts of discovery of salts in the territiry of Siberia",
    year = "1962",
    journal = "Academy of Science of the USSR, Siberian Department, Geology and Geophysics, v. 10, p. 3-22; English translation by American Geological Institute, 1964, International Geology Review, v.6, no.12, p. 2132-2147",
    note = "talkorigins\_source = {true}; raw\_reference = {Yanshin, A. L., 1962, Forecasts of discovery of salts in the territiry of Siberia: Academy of Science of the USSR, Siberian Department, Geology and Geophysics, v. 10, p. 3-22; English translation by American Geological Institute, 1964, International Geology Review, v.6, no.12, p. 2132-2147.}"
}

@misc{zharkov1963cambrian47,
    author = "Zharkov, M. A. and Chechel', E. I. and Knyasev, I. M",
    title = "Cambrian deposits of middle and upper stream of the river Kirenga",
    year = "1963",
    howpublished = "Academy of Sciences of the USSR Reports, v. 149, no. 4, p. 922-924; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.149, p. 65-66",
    note = "talkorigins\_source = {true}; raw\_reference = {Zharkov, M. A., Chechel', E. I., and Knyasev, I. M., 1963, Cambrian deposits of middle and upper stream of the river Kirenga: Academy of Sciences of the USSR Reports, v. 149, no. 4, p. 922-924; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.149, p. 65-66.}"
}

@misc{postnikov1964about34,
    author = "Postnikov, V. G. and Postnikova, I. Y",
    title = "About the possibilities of reef formations in lower Cambrian deposits in Markovskaya reconnaissance area (Irkutskii region)",
    year = "1964",
    howpublished = "Academy of Sciences of the USSR Reports, v. 158, no. 3, p. 605-608; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.158, p. 57-59",
    note = "talkorigins\_source = {true}; raw\_reference = {Postnikov, V. G., and Postnikova, I. Y., 1964, About the possibilities of reef formations in lower Cambrian deposits in Markovskaya reconnaissance area (Irkutskii region): Academy of Sciences of the USSR Reports, v. 158, no. 3, p. 605-608; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.158, p. 57-59.}"
}

@misc{silumov1964about39,
    author = "Silumov, I. N",
    title = "About correlative to Usol'skaya formation and facial structural zones of lower Cambrian foothills of East Sayan",
    year = "1964",
    howpublished = "Academy of Sciences of the USSR Reports, v. 156, no. 4, p. 838-840; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.156, p. 73-75",
    note = "talkorigins\_source = {true}; raw\_reference = {Silumov, I. N., 1964, About correlative to Usol'skaya formation and facial structural zones of lower Cambrian foothills of East Sayan: Academy of Sciences of the USSR Reports, v. 156, no. 4, p. 838-840; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.156, p. 73-75.}"
}

@misc{timofeyev1964about40,
    author = "Timofeyev, B. V. and Bagdasaryan, L. L",
    title = "About the results of micropaleophytological study of oil from East Siberia",
    year = "1964",
    howpublished = "Academy of Sciences of the USSR Reports, v. 154, no. 1, p. 102-103; English translation by American Geological Institute, 1964,Academy of Science, USSR Reports, v.154, p. 22-24",
    note = "talkorigins\_source = {true}; raw\_reference = {Timofeyev, B. V., and Bagdasaryan, L. L., 1964, About the results of micropaleophytological study of oil from East Siberia: Academy of Sciences of the USSR Reports, v. 154, no. 1, p. 102-103; English translation by American Geological Institute, 1964,Academy of Science, USSR Reports, v.154, p. 22-24.}"
}

@misc{brod1965oil13,
    author = "Brod, I. O. and Vysotskiy, I. V",
    title = "Oil and Gas Basins of the World",
    year = "1965",
    howpublished = "Moscow, Nedra Publishing House, 598 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Brod, I. O., and Vysotskiy, I. V., 1965, Oil and Gas Basins of the World: Moscow, Nedra Publishing House, 598 p.}"
}

Abstract The Paradoxissimus Siltstone, representing the Middle Cambrian zone with Tomagnostus fissus and Ptychagnostus atavus in the Öland area, was deposited in a bay under the influence of rhythmic or pendulating current action from NE. Longer periods of mud deposition and an abundant animal life alternated with short periods of silt influx causing a devastation of the mud-burrowing zoocoenoses over large areas. Occasionally the currents turned, transporting some silt in the opposite direction. Among the characteristic animals of the muddy bottoms was the large trilobite Paradoxides paradoxissimus which is found in abundance in the siltstone but only as fossil exuviae; in the shale, representing the environment in which it lived, shelly and trace fossils have been obliterated by diagenetic processes. The silt content in the Paradoxissimus Beds shows lateral variations within the Öland area, and the mainly shaly portions, mostly in the lower part of the sequence, contain better preserved dead trilobites and exuviae in situ. Primary sedimentary structures in connection with the current activity (ripples of different types, traction marks, and priels) are briefly discussed, and the trace fossils are dealt with in more detail. Practical problems in the treatment of trace fossils and ichnocoenoses are discussed as well as some ichnosystematic aspects of the Cambrian “genera” Halopoa and Scotolithus. The Paradoxissimus Siltstone contains hydrocarbons. There are some gas seepages, and surface samples of the siltstone have proved to contain about 0.3% oil.

@article{doi10108011035896509448903,
    author = "Martinsson, Anders",
    title = "Aspects of a Middle Cambrian Thanatotope on Öland",
    year = "1965",
    journal = "Geologiska Föreningen i Stockholm Förhandlingar",
    abstract = "Abstract The Paradoxissimus Siltstone, representing the Middle Cambrian zone with Tomagnostus fissus and Ptychagnostus atavus in the Öland area, was deposited in a bay under the influence of rhythmic or pendulating current action from NE. Longer periods of mud deposition and an abundant animal life alternated with short periods of silt influx causing a devastation of the mud-burrowing zoocoenoses over large areas. Occasionally the currents turned, transporting some silt in the opposite direction. Among the characteristic animals of the muddy bottoms was the large trilobite Paradoxides paradoxissimus which is found in abundance in the siltstone but only as fossil exuviae; in the shale, representing the environment in which it lived, shelly and trace fossils have been obliterated by diagenetic processes. The silt content in the Paradoxissimus Beds shows lateral variations within the Öland area, and the mainly shaly portions, mostly in the lower part of the sequence, contain better preserved dead trilobites and exuviae in situ. Primary sedimentary structures in connection with the current activity (ripples of different types, traction marks, and priels) are briefly discussed, and the trace fossils are dealt with in more detail. Practical problems in the treatment of trace fossils and ichnocoenoses are discussed as well as some ichnosystematic aspects of the Cambrian “genera” Halopoa and Scotolithus. The Paradoxissimus Siltstone contains hydrocarbons. There are some gas seepages, and surface samples of the siltstone have proved to contain about 0.3\% oil.",
    url = "https://doi.org/10.1080/11035896509448903",
    doi = "10.1080/11035896509448903",
    openalex = "W1988675880"
}

@misc{karpyshev1965about23,
    author = "Karpyshev, V. S",
    title = "About the relation between halogenous-carbonate and red- colored Cambrian formations in the western part of the Irkutskii cirque [ampitheatre]",
    year = "1965",
    howpublished = "Academy of Sciences of the USSR Reports, v. 160, no. 2, p. 425-448",
    note = "talkorigins\_source = {true}; raw\_reference = {Karpyshev, V. S., 1965, About the relation between halogenous-carbonate and red- colored Cambrian formations in the western part of the Irkutskii cirque [ampitheatre]: Academy of Sciences of the USSR Reports, v. 160, no. 2, p. 425-448.}"
}

@misc{komar1965additional26,
    author = "Komar, V. A. and Semikhatov, M. A",
    title = "Additional data about the geological history of the Siberian Platform during the late Precambrian",
    year = "1965",
    howpublished = "Academy of Sciences of the USSR Reports, v. 161, no. 2, p. 421-424; English translation by American Geological Institute, 1965, Academy of Science, USSR Doklady, v.161, p. 42-45",
    note = "talkorigins\_source = {true}; raw\_reference = {Komar, V. A., and Semikhatov, M. A., 1965, Additional data about the geological history of the Siberian Platform during the late Precambrian: Academy of Sciences of the USSR Reports, v. 161, no. 2, p. 421-424; English translation by American Geological Institute, 1965, Academy of Science, USSR Doklady, v.161, p. 42-45.}"
}

@misc{popova1965organic33,
    author = "Popova, Z. P. and Glazunova, N. N",
    title = "Organic residues in the oil from Markovskii oil field",
    year = "1965",
    howpublished = "Academy of Sciences of the USSR Reports, v. 161, no. 3, p. 673-675; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.161, p. 67-69",
    note = "talkorigins\_source = {true}; raw\_reference = {Popova, Z. P., and Glazunova, N. N., 1965, Organic residues in the oil from Markovskii oil field: Academy of Sciences of the USSR Reports, v. 161, no. 3, p. 673-675; English translation by American Geological Institute, 1965, Academy of Science, USSR Reports, v.161, p. 67-69.}"
}

@misc{provodnikov1965relief36,
    author = "Provodnikov, L. Y",
    title = "Relief of the foundation of the Siberian Platform",
    year = "1965",
    howpublished = "Academy of Sciences of the USSR Reports, v. 165, no. 8, p. 1379-1382; English translation by American Geological Institute, 1966,Academy of Science, USSR Reports, v.165, p. 99-102",
    note = "talkorigins\_source = {true}; raw\_reference = {Provodnikov, L. Y., 1965, Relief of the foundation of the Siberian Platform: Academy of Sciences of the USSR Reports, v. 165, no. 8, p. 1379-1382; English translation by American Geological Institute, 1966,Academy of Science, USSR Reports, v.165, p. 99-102.}"
}

@misc{zharkova1965carnallite48,
    author = "Zharkova, T. M",
    title = "Carnallite in Cambrian salt deposits of the Siberian Platform",
    year = "1965",
    howpublished = "Academy of Sciences of the USSR Reports, v. 164, no. 1, p. 177- 178; English translation by American Geological Institute, 1966, Academy of Science, USSR Reports, v.164, p. 144-145",
    note = "talkorigins\_source = {true}; raw\_reference = {Zharkova, T. M., 1965, Carnallite in Cambrian salt deposits of the Siberian Platform: Academy of Sciences of the USSR Reports, v. 164, no. 1, p. 177- 178; English translation by American Geological Institute, 1966, Academy of Science, USSR Reports, v.164, p. 144-145.}"
}

@misc{analolyeva1966about4,
    author = "Analol'yeva, A. I. and Kharkov, M. A. and Sovetov, Y. K",
    title = "About correlation of the redcolored layers of the Vendian and the lowest part of the lower Cambrian of the Southwestern part of the Siberian Paltform",
    year = "1966",
    howpublished = "Academy of Sciences of the USSR Reports, v. 166, p. 413-416; English translation by American Geological Institute, 1966, Academy of Sciences USSR Reports, v.166, p. 24-26",
    note = "talkorigins\_source = {true}; raw\_reference = {Analol'yeva, A. I., Kharkov, M. A., and Sovetov, Y. K., 1966, About correlation of the redcolored layers of the Vendian and the lowest part of the lower Cambrian of the Southwestern part of the Siberian Paltform: Academy of Sciences of the USSR Reports, v. 166, p. 413-416; English translation by American Geological Institute, 1966, Academy of Sciences USSR Reports, v.166, p. 24-26.}"
}

@article{drobot1966new16,
    author = "Drobot, D. I. and Isayev, V. P",
    title = "New data about the composition and properties of the lower Cambrian oil of the Prilenskii region of the Irkutskii oil basin",
    year = "1966",
    journal = "Academy of Science of the USSR, Siberian Department, Geology and Geophysics, v. 10, p. 32-41; English translation by American Geological Institute, 1967, International Geological Review, v.9, No.8, p. 1028-1035",
    note = "talkorigins\_source = {true}; raw\_reference = {Drobot, D. I., and Isayev, V. P., 1966, New data about the composition and properties of the lower Cambrian oil of the Prilenskii region of the Irkutskii oil basin: Academy of Science of the USSR, Siberian Department, Geology and Geophysics, v. 10, p. 32-41; English translation by American Geological Institute, 1967, International Geological Review, v.9, No.8, p. 1028-1035.}"
}

@misc{lokhmatov1966change31,
    author = "Lokhmatov, G. I",
    title = "Change of contents of lower Cambrian carbonate deposits under the influence of consediment formation of geological structures (south of Siberian Platform)",
    year = "1966",
    howpublished = "Academy of Sciences of the USSR Reports, v. 170, no. 3, p. 661-664; English translation by American Geological Institute, 1967, Academy of Science, USSR Doklady, v.170, p.88-90",
    note = "talkorigins\_source = {true}; raw\_reference = {Lokhmatov, G. I., 1966, Change of contents of lower Cambrian carbonate deposits under the influence of consediment formation of geological structures (south of Siberian Platform): Academy of Sciences of the USSR Reports, v. 170, no. 3, p. 661-664; English translation by American Geological Institute, 1967, Academy of Science, USSR Doklady, v.170, p.88-90.}"
}

@misc{zhuravleva1966more49,
    author = "Zhuravleva, Z. A. et al",
    title = "More about the stratigraphy of Ushakovskaya formation of the Irkutskii cirque",
    year = "1966",
    howpublished = "Academy of Sciences of the USSR Reports, v. 166, no. 3, p. 678-680; English translation by American Geological Institute, 1966,Academy of Science, USSR Reports, v.166, p. 53-55",
    note = "talkorigins\_source = {true}; raw\_reference = {Zhuravleva, Z. A. et al., 1966, More about the stratigraphy of Ushakovskaya formation of the Irkutskii cirque: Academy of Sciences of the USSR Reports, v. 166, no. 3, p. 678-680; English translation by American Geological Institute, 1966,Academy of Science, USSR Reports, v.166, p. 53-55.}"
}

@techreport{becher1968world11,
    author = "Becher, L. E. and Patton, J. B",
    title = "World occurrance of petroleum in pre- Silurian rocks",
    year = "1968",
    howpublished = "American Association of Petroleum Geologists Bulletin, v. 52, p. 224-245",
    note = "talkorigins\_source = {true}; raw\_reference = {Becher, L. E., and Patton, J. B., 1968, World occurrance of petroleum in pre- Silurian rocks: American Association of Petroleum Geologists Bulletin, v. 52, p. 224-245.}"
}

@misc{kolosov1968complex25,
    author = "Kolosov, A. S. and Pustyl'nikov, A. M. and Kharkova, T. M",
    title = "Complex ferrum and manganese chlorides in Cambrian salt deposits of Kansko-Tassyevskoi basin",
    year = "1968",
    howpublished = "Academy of Sciences of the USSR Reports, v. 181, no. 6, p. 213-216",
    note = "talkorigins\_source = {true}; raw\_reference = {Kolosov, A. S., Pustyl'nikov, A. M., and Kharkova, T. M., 1968, Complex ferrum and manganese chlorides in Cambrian salt deposits of Kansko-Tassyevskoi basin: Academy of Sciences of the USSR Reports, v. 181, no. 6, p. 213-216.}"
}

@misc{moore1968speleothems1,
    author = "Moore, G. W",
    title = "Speleothems, in Fairbridge, R. W., ed., Encyclopedia of Geomorphology",
    year = "1968",
    howpublished = "New York, Reinhold Book Co., p. 1040-1041; 1295 pp",
    note = "talkorigins\_source = {true}; raw\_reference = {Moore, G. W., 1968, Speleothems, in Fairbridge, R. W., ed., Encyclopedia of Geomorphology: New York, Reinhold Book Co., p. 1040-1041; 1295 pp.}"
}

@misc{vasilyev1968gas41,
    author = "Vasil'yev, V. G",
    title = "Gas reservoirs of the USSR",
    year = "1968",
    howpublished = "Moscow, Nedra Publishing House, 382 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Vasil'yev, V. G., 1968, Gas reservoirs of the USSR: Moscow, Nedra Publishing House, 382 p.}"
}

@misc{zolotov1968structure50,
    author = "Zolotov, A. N. et al",
    title = "Structure of the gas condensate deposit of Parfenovskii horizon of Markovskii oil field",
    year = "1968",
    howpublished = "Geology of Oil and Gas, v. 6, p. 26-30",
    note = "talkorigins\_source = {true}; raw\_reference = {Zolotov, A. N. et al., 1968, Structure of the gas condensate deposit of Parfenovskii horizon of Markovskii oil field: Geology of Oil and Gas, v. 6, p. 26-30.}"
}

@misc{bakirov1969oil7,
    author = "Bakirov, A. A. and Ryabuknin, G. Y",
    title = "Oil and Gas Bearing Areas and Regions of the USSR",
    year = "1969",
    howpublished = "Moscow, Nedra Publishing House, 477 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Bakirov, A. A., and Ryabuknin, G. Y., 1969, Oil and Gas Bearing Areas and Regions of the USSR: Moscow, Nedra Publishing House, 477 p.}"
}

@misc{korolyuk1969stromatolites28,
    author = "Korolyuk, I. K. and Sidorov, A. D",
    title = "Stromatolites of Motskaya formation of southern part of Pribaykal'ya and southeastern part of Prisayan'ya",
    year = "1969",
    howpublished = "Academy of Sciences of the USSR Reports, v. 184, no. 3, p. 669-671; English translation by American Geological Institute, 1969, Academy of Science, USSR Doklady, v.184, p. 53-56",
    note = "talkorigins\_source = {true}; raw\_reference = {Korolyuk, I. K., and Sidorov, A. D., 1969, Stromatolites of Motskaya formation of southern part of Pribaykal'ya and southeastern part of Prisayan'ya: Academy of Sciences of the USSR Reports, v. 184, no. 3, p. 669-671; English translation by American Geological Institute, 1969, Academy of Science, USSR Doklady, v.184, p. 53-56.}"
}

@misc{postnikova1969new35,
    author = "Postnikova, I. Y. and Kotel'nikov, D. D",
    title = "New data about the signs of volcanic activity in Vendian deposits of Irkutsk cirque",
    year = "1969",
    howpublished = "Academy of Sciences of the USSR Reports, v. 186, no. 5, p. 1146-1149; English translation by American Geological Institute, 1970, Academy of Science, USSR Reports, v.186, No.5, p. 83-86",
    note = "talkorigins\_source = {true}; raw\_reference = {Postnikova, I. Y., and Kotel'nikov, D. D., 1969, New data about the signs of volcanic activity in Vendian deposits of Irkutsk cirque: Academy of Sciences of the USSR Reports, v. 186, no. 5, p. 1146-1149; English translation by American Geological Institute, 1970, Academy of Science, USSR Reports, v.186, No.5, p. 83-86.}"
}

@misc{zharkov1969about46,
    author = "Zharkov, M. A",
    title = "About the amounts of salt deposits in the Cambrian era",
    year = "1969",
    howpublished = "Academy of Sciences of the USSR Reports, v. 184, no. 4, p. 913-914; English translation by American Geological Institute, 1969,Academy of Science, USSR Reports, v.184, p. 72-74",
    note = "talkorigins\_source = {true}; raw\_reference = {Zharkov, M. A., 1969, About the amounts of salt deposits in the Cambrian era: Academy of Sciences of the USSR Reports, v. 184, no. 4, p. 913-914; English translation by American Geological Institute, 1969,Academy of Science, USSR Reports, v.184, p. 72-74.}"
}

@misc{gladkov1970about20,
    author = "Gladkov, V. G. and Nikitin, V. P. and Khrenov, P. M",
    title = "About the question of kinematics of halogenating in the profiles and in the folded belt of the Southern part of the Siberian Platform",
    year = "1970",
    howpublished = "Academy of Sciences of the USSR Reports, v. 190, no. 2, p. 405-408; English translation by the American Geological Institute, 1970, Academy of Science, USSR Doklady, v.190, p. 42- 45",
    note = "talkorigins\_source = {true}; raw\_reference = {Gladkov, V. G., Nikitin, V. P., and Khrenov, P. M., 1970, About the question of kinematics of halogenating in the profiles and in the folded belt of the Southern part of the Siberian Platform: Academy of Sciences of the USSR Reports, v. 190, no. 2, p. 405-408; English translation by the American Geological Institute, 1970, Academy of Science, USSR Doklady, v.190, p. 42- 45.}"
}

@misc{samsonov1970about38,
    author = "Samsonov, V. V. and Tyshchenko, L. F",
    title = "About genetic connections between gasses from the closed pores and gasses from the productive seams",
    year = "1970",
    howpublished = "Geology of Oil and Gas, v. 8, p. 33-36",
    note = "talkorigins\_source = {true}; raw\_reference = {Samsonov, V. V., and Tyshchenko, L. F., 1970, About genetic connections between gasses from the closed pores and gasses from the productive seams: Geology of Oil and Gas, v. 8, p. 33-36.}"
}

@article{vassoyevich1970more43,
    author = "Vassoyevich, N. B. et al",
    title = "More about the question of oil and gas prospects in late Cambrian deposits",
    year = "1970",
    journal = "Soviet Geology, v. 4, p. 66-79; English translation by American Geological Institute, 1971, International Geology Review, v.13, No.3, p. 407-418",
    note = "talkorigins\_source = {true}; raw\_reference = {Vassoyevich, N. B. et al., 1970, More about the question of oil and gas prospects in late Cambrian deposits: Soviet Geology, v. 4, p. 66-79; English translation by American Geological Institute, 1971, International Geology Review, v.13, No.3, p. 407-418.}"
}

@misc{garilov1971about19,
    author = "Garilov, Y. Y. and Kulibakina, I. B. and Teplinskiy, G. I",
    title = "About the formation of hydrocarbon deposits of Markovskii oil field",
    year = "1971",
    howpublished = "Geology of Oil and Gas, v. 2, p. 30-31",
    note = "talkorigins\_source = {true}; raw\_reference = {Garilov, Y. Y., Kulibakina, I. B., and Teplinskiy, G. I., 1971, About the formation of hydrocarbon deposits of Markovskii oil field: Geology of Oil and Gas, v. 2, p. 30-31.}"
}

@misc{karasev1971conditions22,
    author = "Karasev, O. I. et al",
    title = "Conditions for formation and accumulation of oil and gas in Vendian and Cambrian deposits of the southern part of the Siberian Platform",
    year = "1971",
    howpublished = "Irkutsk, East Siberian Publishing House, 206 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Karasev, O. I. et al., 1971, Conditions for formation and accumulation of oil and gas in Vendian and Cambrian deposits of the southern part of the Siberian Platform: Irkutsk, East Siberian Publishing House, 206 p.}"
}

@misc{bazanov1973geological9,
    author = "Bazanov, E. A",
    title = "Geological structure of Yaraktinskoye oil field in Irkutsk region",
    year = "1973",
    howpublished = "Geology of Oil and Gas, v. 7, p. 15-18",
    note = "talkorigins\_source = {true}; raw\_reference = {Bazanov, E. A., 1973, Geological structure of Yaraktinskoye oil field in Irkutsk region: Geology of Oil and Gas, v. 7, p. 15-18.}"
}

@misc{mitroshin1974prospects32,
    author = "Mitroshin, M. I. and Gvizd', D. I",
    title = "Prospects of oil and gas in the norhtwestern part of the Tungusskii syneclise",
    year = "1974",
    howpublished = "Soviet Geology, v. 4, p. 45- 51",
    note = "talkorigins\_source = {true}; raw\_reference = {Mitroshin, M. I., and Gvizd', D. I., 1974, Prospects of oil and gas in the norhtwestern part of the Tungusskii syneclise: Soviet Geology, v. 4, p. 45- 51.}"
}

@inproceedings{holmgern1975the21,
    author = "Holmgern, D. A. and Moody, J. D. and Emmerich, H. H",
    title = "The structural settings for giant oil and gas fields",
    year = "1975",
    booktitle = "9th World Petroleum Congress (Tokyo) Proceedings, v. 2, p. 45-54",
    note = "talkorigins\_source = {true}; raw\_reference = {Holmgern, D. A., Moody, J. D., and Emmerich, H. H., 1975, The structural settings for giant oil and gas fields: 9th World Petroleum Congress (Tokyo) Proceedings, v. 2, p. 45-54.}"
}

@misc{levchenko1975prospects30,
    author = "Levchenko, I. G",
    title = "Prospects of oil and gas in Cambrian deposits of Tungusskaya syneclise and its belt",
    year = "1975",
    howpublished = "Geology of Oil and Gas, v. 1, p. 1-9",
    note = "talkorigins\_source = {true}; raw\_reference = {Levchenko, I. G., 1975, Prospects of oil and gas in Cambrian deposits of Tungusskaya syneclise and its belt: Geology of Oil and Gas, v. 1, p. 1-9.}"
}

@misc{vasilyev1975gas42,
    author = "Vasil'yev, V. G. and Zhabrev, I. P",
    title = "Gas and gas condensate reservoirs, a reference book",
    year = "1975",
    howpublished = "Moscow, Nedra Publishing House, 527 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Vasil'yev, V. G., and Zhabrev, I. P., 1975, Gas and gas condensate reservoirs, a reference book: Moscow, Nedra Publishing House, 527 p.}"
}

@misc{akulcheeva1976about3,
    author = "Akul'cheeva, Z. A. and Fayzulina, Z. K",
    title = "About comparing lower Paleozoic deposits of Prelenskii and Botuobinskii regions of Bepskii arch",
    year = "1976",
    howpublished = "Geologiya i Geofizica, v. 7, p. 10-17",
    note = "talkorigins\_source = {true}; raw\_reference = {Akul'cheeva, Z. A., and Fayzulina, Z. K., 1976, About comparing lower Paleozoic deposits of Prelenskii and Botuobinskii regions of Bepskii arch: Geologiya i Geofizica, v. 7, p. 10-17.}"
}

ABSTRACT Cores of shoreface sediments off Fire Island, Long Island, New York, in water depths ranging between 5 and 21 m, contain a distinctive three-part sequence; from base upward consisting of: (a) basal lag, up to 50 cm thick, containing coarse gravel; (b) finely laminated sand up to 2 m thick, having median diameters ranging from 0.210 to 0.125 ram, and (c) burrow-mottled sand coarser in size than unit (b), up to 30 cm thick. The boundaries between (a), (b), and (c) are sharp. The relatively coarser, mottled sand composing the upper part of this sequence results from processes operating in the shoreface zone during fair weather. Such processes create either wave-ripple laminae (between wave base and the breaker zone) or burrow-mottled sediment (seaward of wave base). The lower part of the sequence is inferred to result from storms. The basal gravel is interpreted as a lag formed during maximum storm intensity when the coarse material is jostled at the bottom and the finer sediment is kept dispersed or is in turbulent suspension. The fined laminated sand is inferred to have been rapidly deposited under conditions of intense bottom shear as the storm waned. Examples in the geologic record of what we regard as comparable storm-deposited sequences occur at the following locations: Relict Holocene sediments off Fire Island, New York; Pleistocene sediments underlying Fire Island barrier, Long Island, New York; Norfolk Formation (Pleistocene), Benns Church, southeastern Virginia; Eocene and conglomerates, Tehachapi and San Emigdio Mountains, southern California; and Cambrian and conglomerates, Parfrey's Glen, Baraboo Range, Wisconsin. In addition, other workers have identified characteristic sequences very similar to the one described here in the following localities: Recent sediments off Virginia; Recent sediments, southern North Sea; upper part of Sundance Formation (Jurassic) of Wyoming and Montana; Upper Cambrian, Ba aboo district, Wisconsin; and sublittoral sheet sandstones described from several locations. We speculate that the geologic record of shoreface sediments contains a minimal proportion of sediments deposited during fair-weather conditions and consists largely of storm deposits.

@article{doi101306212f6edd2b2411d78648000102c1865d,
    author = "Kumar, Naresh",
    title = "Characteristics of Shoreface Storm Deposits: Modern and Ancient Examples",
    year = "1976",
    journal = "Journal of Sedimentary Research",
    abstract = "ABSTRACT Cores of shoreface sediments off Fire Island, Long Island, New York, in water depths ranging between 5 and 21 m, contain a distinctive three-part sequence; from base upward consisting of: (a) basal lag, up to 50 cm thick, containing coarse gravel; (b) finely laminated sand up to 2 m thick, having median diameters ranging from 0.210 to 0.125 ram, and (c) burrow-mottled sand coarser in size than unit (b), up to 30 cm thick. The boundaries between (a), (b), and (c) are sharp. The relatively coarser, mottled sand composing the upper part of this sequence results from processes operating in the shoreface zone during fair weather. Such processes create either wave-ripple laminae (between wave base and the breaker zone) or burrow-mottled sediment (seaward of wave base). The lower part of the sequence is inferred to result from storms. The basal gravel is interpreted as a lag formed during maximum storm intensity when the coarse material is jostled at the bottom and the finer sediment is kept dispersed or is in turbulent suspension. The fined laminated sand is inferred to have been rapidly deposited under conditions of intense bottom shear as the storm waned. Examples in the geologic record of what we regard as comparable storm-deposited sequences occur at the following locations: Relict Holocene sediments off Fire Island, New York; Pleistocene sediments underlying Fire Island barrier, Long Island, New York; Norfolk Formation (Pleistocene), Benns Church, southeastern Virginia; Eocene and conglomerates, Tehachapi and San Emigdio Mountains, southern California; and Cambrian and conglomerates, Parfrey's Glen, Baraboo Range, Wisconsin. In addition, other workers have identified characteristic sequences very similar to the one described here in the following localities: Recent sediments off Virginia; Recent sediments, southern North Sea; upper part of Sundance Formation (Jurassic) of Wyoming and Montana; Upper Cambrian, Ba aboo district, Wisconsin; and sublittoral sheet sandstones described from several locations. We speculate that the geologic record of shoreface sediments contains a minimal proportion of sediments deposited during fair-weather conditions and consists largely of storm deposits.",
    url = "https://doi.org/10.1306/212f6edd-2b24-11d7-8648000102c1865d",
    doi = "10.1306/212f6edd-2b24-11d7-8648000102c1865d",
    openalex = "W2146889231"
}

@book{dubronin1976conditions17,
    author = "Dubronin, M. A",
    title = "Conditions for formation of salt structures of Angaro- Lenskogo depression",
    year = "1976",
    publisher = "Geologiya i Geofizica, v. 6, p. 60-67",
    note = "talkorigins\_source = {true}; raw\_reference = {Dubronin, M. A., 1976, Conditions for formation of salt structures of Angaro- Lenskogo depression: Geologiya i Geofizica, v. 6, p. 60-67.}"
}

@misc{balitov1977about8,
    author = "Balitov, N. V",
    title = "About genesis of sulphurous oils and hydrogen sulphide in gasses from Osinskii horizon of Irkutskii cirque",
    year = "1977",
    howpublished = "Geologiya i Geofizica, v. 9, p. 47-55",
    note = "talkorigins\_source = {true}; raw\_reference = {Balitov, N. V., 1977, About genesis of sulphurous oils and hydrogen sulphide in gasses from Osinskii horizon of Irkutskii cirque: Geologiya i Geofizica, v. 9, p. 47-55.}"
}

@misc{bazanov1977improving10,
    author = "Bazanov, E. A. and Vereshchako, I. A. and Frolov, B. M",
    title = "Improving the methods and ways to increase effectiveness of geological oil and gas reconnaissance works in Irkutsk cirque",
    year = "1977",
    howpublished = "Geology of Oil and Gas, v. 2, p. 9- 13",
    note = "talkorigins\_source = {true}; raw\_reference = {Bazanov, E. A., Vereshchako, I. A., and Frolov, B. M., 1977, Improving the methods and ways to increase effectiveness of geological oil and gas reconnaissance works in Irkutsk cirque: Geology of Oil and Gas, v. 2, p. 9- 13.}"
}

@article{beck1977caves,
    author = "BECK, B. F.",
    title = "Caves",
    year = "1977",
    journal = "Science",
    url = "https://doi.org/10.1126/science.195.4280.776",
    doi = "10.1126/science.195.4280.776",
    number = "4280",
    pages = "776-776",
    volume = "195"
}

@misc{dikenshteyn1977oil15,
    author = "Dikenshteyn, G. K. et al",
    title = "Oil and Gas Regions of the USSR",
    year = "1977",
    howpublished = "Moscow, Nedra Publishing House, 328 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Dikenshteyn, G. K. et al., 1977, Oil and Gas Regions of the USSR: Moscow, Nedra Publishing House, 328 p.}"
}

ABSTRACT The Cadomin Formation, the basal unit of the Lower Cretaceous Blairmore Group, is one of the most prominent and useful stratigraphic markers in the Rocky Mountain Foothills, yet has received little attention in the literature. The formation ranges from 0 to at least 200 m (660 ft) in thickness, and is composed entirely of conglomerate at some localities but contains abundant interbedded sand and finer clastics elsewhere. Gravel-size clasts are mainly subrounded to well rounded, have an average size of 1 to 3 cm (0.4 to 1.2 in) and a maximum size up to 40 cm (16 in). A long period of pedimentation accompanied formation of the Cadomin, with removal of hundreds of metres of older sediments in eastern areas but possibly with continuous sedimentation to the west. Extensive areas covered by a single thin bed of conglomerate are remnants of the pediment surface, whereas thicker conglomerate and sandstone sequences are of alluvial-fan and fluvial origin, mostly deposited under humid conditions. These fans and rivers fed a trunk stream, the Spirit River Channel, flowing northwestward and bounded on the east by an erosional scarp, the Fox Creek Escarpment. This channel and scarp were formed and maintained during pedimentation, and transported finer detritus northwestward, possibly to be deposited in the Peace River autogeosyncline, the Bowser Basin, and in the Mackenzie Delta area. Thickness and clast size indicate a western provenance, the location of which is uncertain but included parts of the region west of the present-day Rocky Mountain Trench, and probably parts of the Main Ranges of the Rocky Mountains. Coarsest clast sizes occur where the horizontal movements accompanying thrusting encountered areas with histories of vertical movement -- the Peace River Arch and the Sweetgrass-Belt Arches. The mountain front was less bowed than at present and more nearly parallel with the Fox Creek Escarpment. A large alluvial fan in the Smoky River region separates an area to the north with thick coal seams in the post-Cadomin strata from an area to the south with only thin coal beds.

@article{doi1035767gscpgbull254792,
    author = "McLean, J. Ross",
    title = "The Cadomin Formation: Stratigraphy, Sedimentology, and Tectonic Implications",
    year = "1977",
    journal = "Bulletin of Canadian Petroleum Geology",
    abstract = "ABSTRACT The Cadomin Formation, the basal unit of the Lower Cretaceous Blairmore Group, is one of the most prominent and useful stratigraphic markers in the Rocky Mountain Foothills, yet has received little attention in the literature. The formation ranges from 0 to at least 200 m (660 ft) in thickness, and is composed entirely of conglomerate at some localities but contains abundant interbedded sand and finer clastics elsewhere. Gravel-size clasts are mainly subrounded to well rounded, have an average size of 1 to 3 cm (0.4 to 1.2 in) and a maximum size up to 40 cm (16 in). A long period of pedimentation accompanied formation of the Cadomin, with removal of hundreds of metres of older sediments in eastern areas but possibly with continuous sedimentation to the west. Extensive areas covered by a single thin bed of conglomerate are remnants of the pediment surface, whereas thicker conglomerate and sandstone sequences are of alluvial-fan and fluvial origin, mostly deposited under humid conditions. These fans and rivers fed a trunk stream, the Spirit River Channel, flowing northwestward and bounded on the east by an erosional scarp, the Fox Creek Escarpment. This channel and scarp were formed and maintained during pedimentation, and transported finer detritus northwestward, possibly to be deposited in the Peace River autogeosyncline, the Bowser Basin, and in the Mackenzie Delta area. Thickness and clast size indicate a western provenance, the location of which is uncertain but included parts of the region west of the present-day Rocky Mountain Trench, and probably parts of the Main Ranges of the Rocky Mountains. Coarsest clast sizes occur where the horizontal movements accompanying thrusting encountered areas with histories of vertical movement -- the Peace River Arch and the Sweetgrass-Belt Arches. The mountain front was less bowed than at present and more nearly parallel with the Fox Creek Escarpment. A large alluvial fan in the Smoky River region separates an area to the north with thick coal seams in the post-Cadomin strata from an area to the south with only thin coal beds.",
    url = "https://doi.org/10.35767/gscpgbull.25.4.792",
    doi = "10.35767/gscpgbull.25.4.792",
    openalex = "W1764912929"
}

@misc{kontorovich1977main27,
    author = "Kontorovich, A. A. et al",
    title = "Main steps and results of reconnaissance in West Siberian oil and gas province",
    year = "1977",
    howpublished = "Geology of Oil and Gas, v. 11, p. 21- 25",
    note = "talkorigins\_source = {true}; raw\_reference = {Kontorovich, A. A. et al., 1977, Main steps and results of reconnaissance in West Siberian oil and gas province: Geology of Oil and Gas, v. 11, p. 21- 25.}"
}

@misc{kutukov1977prospects29,
    author = "Kutukov, A. V. and Vinnikovskiy, S. A. and Shershnev, K. S",
    title = "Prospects of oil and gas in Vendian deposits of Permskii Prikam'ya",
    year = "1977",
    howpublished = "Geology of Oil and Gas, v. 11, p. 37-43",
    note = "talkorigins\_source = {true}; raw\_reference = {Kutukov, A. V., Vinnikovskiy, S. A., and Shershnev, K. S., 1977, Prospects of oil and gas in Vendian deposits of Permskii Prikam'ya: Geology of Oil and Gas, v. 11, p. 37-43.}"
}

@misc{samsonov1977epigenetic37,
    author = "Samsonov, V. V. et al",
    title = "Epigenetic cementation of terrigenous collectors and special features of bitumonites spreading on the southern slope of the Nepskii arch",
    year = "1977",
    howpublished = "Geology of Oil and Gas, v. 2, p. 18-25",
    note = "talkorigins\_source = {true}; raw\_reference = {Samsonov, V. V. et al., 1977, Epigenetic cementation of terrigenous collectors and special features of bitumonites spreading on the southern slope of the Nepskii arch: Geology of Oil and Gas, v. 2, p. 18-25.}"
}

@misc{babintseva1978hydrogeochemical5,
    author = "Babintseva, T. N. et al",
    title = "Hydrogeochemical conditions of the oil and gas reserves of the Tunguska basin",
    year = "1978",
    howpublished = "Geology of Oil and Gas, v. 3, p. 30-36",
    note = "talkorigins\_source = {true}; raw\_reference = {Babintseva, T. N. et al., 1978, Hydrogeochemical conditions of the oil and gas reserves of the Tunguska basin: Geology of Oil and Gas, v. 3, p. 30-36.}"
}

@misc{belenkiy1978ways12,
    author = "Belen'kiy, V. Y. and Kunin, N. Y",
    title = "Ways of improving the effectiveness of seismic reconnaissance when preparing [investigating] structures in Western Yakutia",
    year = "1978",
    howpublished = "Geology of Oil and Gas, v. 5, p. 22-30",
    note = "talkorigins\_source = {true}; raw\_reference = {Belen'kiy, V. Y., and Kunin, N. Y., 1978, Ways of improving the effectiveness of seismic reconnaissance when preparing [investigating] structures in Western Yakutia: Geology of Oil and Gas, v. 5, p. 22-30.}"
}

@misc{kazanskii1978methods24,
    author = "Kazanskii, V. V. et al",
    title = "Methods of influencing low permeability collector seams of East Siberia during teats",
    year = "1978",
    howpublished = "Geology of Oil and Gas, v. 4, p. 60-64",
    note = "talkorigins\_source = {true}; raw\_reference = {Kazanskii, V. V. et al., 1978, Methods of influencing low permeability collector seams of East Siberia during teats: Geology of Oil and Gas, v. 4, p. 60-64.}"
}

@misc{vysotskiy1978prospects44,
    author = "Vysotskiy, I. V. and Larchenkov, Y. P. and Sokolov, B. A",
    title = "Prospects of oil and gas in the southeastern part of Leno-Vilyuyskogo basin",
    year = "1978",
    howpublished = "Geology of Oil and Gas, v. 5, p. 31-35",
    note = "talkorigins\_source = {true}; raw\_reference = {Vysotskiy, I. V., Larchenkov, Y. P., and Sokolov, B. A., 1978, Prospects of oil and gas in the southeastern part of Leno-Vilyuyskogo basin: Geology of Oil and Gas, v. 5, p. 31-35.}"
}

@misc{bakirov1979oil6,
    author = "Bakirov, A. A",
    title = "Oil and Gas Bearing Areas and Regions of the USSR",
    year = "1979",
    howpublished = "Moscow, Nedra Publishing House, 456 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Bakirov, A. A., 1979, Oil and Gas Bearing Areas and Regions of the USSR: Moscow, Nedra Publishing House, 456 p.}"
}

@misc{fuks1979genesis18,
    author = "Fuks, A. B. and Fuks, B. A",
    title = "Genesis of the oil belt of the Nepsko- Butoubiskoy anticline deposits",
    year = "1979",
    howpublished = "Geology of Oil and Gas, v. 2, p. 13-18",
    note = "talkorigins\_source = {true}; raw\_reference = {Fuks, A. B., and Fuks, B. A., 1979, Genesis of the oil belt of the Nepsko- Butoubiskoy anticline deposits: Geology of Oil and Gas, v. 2, p. 13-18.}"
}

ABSTRACT The Nolichucky Formation (0–300 m thick) formed on the Cambrian pericratonic shelf in a shallow intrashelf basin bordered along strike and toward the regional shelf edge by shallow water carbonates and by nearshore clastics toward the craton. Lateral facies changes from shallow basinal rocks to peritidal carbonates suggest that the intrashelf basin was bordered by a gently sloping carbonate ramp. Peritidal facies of the regional shelf are cyclic, upward‐shallowing stromatolitic carbonates. These grade toward the intrashelf basin into shallow ramp, cross‐bedded, ooid and oncolitic, intraclast grain‐stones that pass downslope into deeper ramp, subwave base, ribbon carbonates and thin limestone conglomerate. Ribbon limestones are layers and lenses of trilobite packstone, parallel and wave‐ripple‐laminated, quartzose calcisiltite, and lime mudstone arranged in storm‐generated, fining upward sequences (1–5 cm thick) that may be burrowed. Shallow basin facies are storm generated, upward coarsening and upward fining sequences of green, calcareous shale with open marine biota; parallel to hummocky laminated calcareous siltstone; and intraformational flat pebble conglomerate. There are also rare debris‐flow paraconglomerate (10–60 cm thick) and shaly packstone/wackestone with trace fossils, glauconite horizons and erosional surfaces/hardgrounds. A 15‐m thick tongue of cyclic carbonates within the shale package contains subtidal digitate algal bioherms which developed during a period of shoaling in the basin. Understanding the Nolichucky facies within a ramp to intrashelf basin model provides a framework for understanding similar facies which are widely distributed in the Lower Palaeozoic elsewhere. The study demonstrates the widespread effects of storm processes on pericratonic shelf sedimentation. Finally, recognition of shallow basins located on pericratonic shelves is important because such basins influence the distribution of facies and reservoir rocks, whose trends may be unrelated to regional shelf‐edge trends.

@article{doi101111j136530911981tb01702x,
    author = "Markello, James R. and Read, J. F.",
    title = "Carbonate ramp‐to‐deeper shale shelf transitions of an Upper Cambrian intrashelf basin, Nolichucky Formation, Southwest Virginia Appalachians",
    year = "1981",
    journal = "Sedimentology",
    abstract = "ABSTRACT The Nolichucky Formation (0–300 m thick) formed on the Cambrian pericratonic shelf in a shallow intrashelf basin bordered along strike and toward the regional shelf edge by shallow water carbonates and by nearshore clastics toward the craton. Lateral facies changes from shallow basinal rocks to peritidal carbonates suggest that the intrashelf basin was bordered by a gently sloping carbonate ramp. Peritidal facies of the regional shelf are cyclic, upward‐shallowing stromatolitic carbonates. These grade toward the intrashelf basin into shallow ramp, cross‐bedded, ooid and oncolitic, intraclast grain‐stones that pass downslope into deeper ramp, subwave base, ribbon carbonates and thin limestone conglomerate. Ribbon limestones are layers and lenses of trilobite packstone, parallel and wave‐ripple‐laminated, quartzose calcisiltite, and lime mudstone arranged in storm‐generated, fining upward sequences (1–5 cm thick) that may be burrowed. Shallow basin facies are storm generated, upward coarsening and upward fining sequences of green, calcareous shale with open marine biota; parallel to hummocky laminated calcareous siltstone; and intraformational flat pebble conglomerate. There are also rare debris‐flow paraconglomerate (10–60 cm thick) and shaly packstone/wackestone with trace fossils, glauconite horizons and erosional surfaces/hardgrounds. A 15‐m thick tongue of cyclic carbonates within the shale package contains subtidal digitate algal bioherms which developed during a period of shoaling in the basin. Understanding the Nolichucky facies within a ramp to intrashelf basin model provides a framework for understanding similar facies which are widely distributed in the Lower Palaeozoic elsewhere. The study demonstrates the widespread effects of storm processes on pericratonic shelf sedimentation. Finally, recognition of shallow basins located on pericratonic shelves is important because such basins influence the distribution of facies and reservoir rocks, whose trends may be unrelated to regional shelf‐edge trends.",
    url = "https://doi.org/10.1111/j.1365-3091.1981.tb01702.x",
    doi = "10.1111/j.1365-3091.1981.tb01702.x",
    openalex = "W2145649605",
    references = "doi1010079783642814983, doi1010160025322767900515, doi1010160037073868900249, doi1010160040195175901390, doi101016s0070457108x70451, doi101130001676061970811031lpmtat20co2, doi101139e79156, doi101306212f79782b2411d78648000102c1865d, doi10130674d7185c2b2111d78648000102c1865d, doi1023071796776, openalexw1575605242, openalexw630270902"
}

The Cambrian System holds special scientific interest because it contains the primary record of the earliest evolutionary diversification of metazoan life on Earth. Study of the patterns of evolutionary diversification and associated environmental conditions provides our understanding of the original colonization of the Earth's marine ecosystem by complex plant and animal communities. Rocks of Cambrian age contain a significant portion of the world's sedimentary and metallic mineral resources. Increased understanding of Cambrian stratigraphy, depositional environments, and paleogeography improves our ability to discover new deposits which are so necessary to the agricultural and industrial well being of the world's human population. This volume is the proceedings of the technical sessions of the Second International Symposium on the Cambrian System, held August 9-13, 1981, in Golden, Colorado. The first international Cambrian symposium was held in conjunction with the 20th International Geological Congress in Mexico City in 1956. Since 1956, a wealth of research on Cambrian stratigraphy and paleontology has been conducted in all parts of the world. This volume contains a sample of that work in 72 scientific reports authored or coauthored by 95 research scientists. Thirteen countries are represented by the contributors, including the United States of America (37), the Union of Soviet Socialist Republics (16), the People's Republic of China (12), England (6), Australia (5), Sweden (5), Canada (3), France (3), Argentina (2), Estonia (2), West Germany (2), South Korea (1), and Poland (1).

@article{doi103133ofr81743,
    author = "Taylor, Michael E. and Mintinc, U Wvemweiit and Palmer, Allison and Robison, Richard and Rowell, Albert and Espizua, Stella and Roberto, Caminos and Toselli, Rossi De and Salfity, J and Toselli, A and Godeas, J and Lunatus, E Nordenskioeldi and Inflata, S and Spinosa, S and Kullingi, S and Fm, Gislbv and 2, / and Sh, Ekre and Ss, Kalmarsund and Grandis, H and Mobergi, H and Yenhao, Lu and Zhaoling, Zhu and Acerolaza, P and Ahlberg, Per and Cook, H and P, En and Kopaska-Merkel, D and Kurtz, V and P, En and Lafuste, J and Cl and Miller and Parrish, J and P, Tn and Pojeta, John and Repetski, J and P, En and Brasier, M and Hewitt, R and Brasier, C and Brasier, M and Hewitt, R and Cobbold, E and Cobbold, E and Pocock, R and Cowie, J and Rushton, A and Stubblefield, C and Fritz, W and Grabau, A and Hupe, Pierre and Landing, E and Nowland, G and Fletcher, T and Matthew, G and Matthews, S and Cowie, J and Matthews, S and Missarzhevsky, V and Patchett, J and Gale, N and Goodwin, R and Humm, M and Poulsen, Christian and Poulsen, V and Rozanov, A and Yu and Rushton, A and Walcott, C and Crevello, P and Schlager, W and Dietz, R and Holden, J and Edgar, N and Saunders, J and Embley, R and Fan, Pow-Foong and Rex and Cook, R and Zemmels, H and Edgar, I M^ and Saunders, N and J and Johns, D and Mutti, E and Resell, J and Deguret, M and Kay, M and Mountjoy, E and Cook, H and Pray, L and Mcdaniel, P and Redfield, A and Ketchum, B and Richards, F and Rees, M and Rowell, A and Schlager, W and Chermak, A",
    title = "Short papers for the Second International Symposium on the Cambrian System, 1981",
    year = "1981",
    journal = "Antarctica A Keystone in a Changing World",
    abstract = "The Cambrian System holds special scientific interest because it contains the primary record of the earliest evolutionary diversification of metazoan life on Earth. Study of the patterns of evolutionary diversification and associated environmental conditions provides our understanding of the original colonization of the Earth's marine ecosystem by complex plant and animal communities. Rocks of Cambrian age contain a significant portion of the world's sedimentary and metallic mineral resources. Increased understanding of Cambrian stratigraphy, depositional environments, and paleogeography improves our ability to discover new deposits which are so necessary to the agricultural and industrial well being of the world's human population. This volume is the proceedings of the technical sessions of the Second International Symposium on the Cambrian System, held August 9-13, 1981, in Golden, Colorado. The first international Cambrian symposium was held in conjunction with the 20th International Geological Congress in Mexico City in 1956. Since 1956, a wealth of research on Cambrian stratigraphy and paleontology has been conducted in all parts of the world. This volume contains a sample of that work in 72 scientific reports authored or coauthored by 95 research scientists. Thirteen countries are represented by the contributors, including the United States of America (37), the Union of Soviet Socialist Republics (16), the People's Republic of China (12), England (6), Australia (5), Sweden (5), Canada (3), France (3), Argentina (2), Estonia (2), West Germany (2), South Korea (1), and Poland (1).",
    url = "https://doi.org/10.3133/ofr81743",
    doi = "10.3133/ofr81743",
    openalex = "W64497491",
    references = "doi1010160012825272900724, doi101017s0094837300003778, doi101017s0094837300005972, doi101017s0094837300006539, doi101017s0094837300006588, doi101146annureven10010165000525, doi1023071441916, doi1023072412825, doi1023072806339, openalexw1488584644"
}

The Avalon tectonostratigraphic zone occupies about 25% of the area of insular Newfoundland. Late Precambrian development of the Avalon terrane is distinctly different than that of other parts of the Appalachian orogen and cratonic North America. Late Precambrian volcanism and tectonic instability gave way to deposition of about 2 km of Cambrian and Lower Ordovician dominantly epiclastic sediments on a slowly subsiding, relatively stable shelf platform.The Lower Cambrian Random Formation is part of the platformal sequence and is bounded by regional disconformities over much of the Newfoundland Avalon Zone, except around Fortune Bay where it is underlain by older terrestrial and shallow-marine sediments. The Random Formation was deposited during a time of global sea-level rise, and consists of up to 250 m of shoreline, nearshore, and open-shelf deposits that record macrotidal conditions and periodic storm activity. Cross-bedded quartzarenites occur in units to about 50 m thick (one exceptional unit is 110 m thick) that tend to have gradational bases and abrupt tops. Bimodal–bipolar paleocurrent data are best explained by reversing tidal currents. These sandstone units show no evidence of intertidal (beach) processes and are therefore interpreted as subtidal ridges or shoals. The intertidal environment is represented by a shaly unit, with thin sandstone beds, that is characterized by flaser and lenticular bedding, oscillation (wave) ripples, some flat-topped ripples, and abundant synaeresis (dehydration) cracks. A muddy shoreline and subtidal sands suggest a macrotidal setting.Storm deposits range from: (1) fine, micaceous, red sandstones with fiat, gently dipping lamination, low-angle truncation surfaces, rare hummocks, shale-clast horizons, granule lags, and steep-sided erosional gulleys believed to represent lower shoreface rip-current channels; to (2) mudstones with graded, sole-marked, glauconitic sandstone beds deposited on an open shelf by storm-generated density currents.

@article{hiscott1982tidal,
    author = "Hiscott, Richard N.",
    title = "Tidal deposits of the Lower Cambrian Random Formation, eastern Newfoundland: facies and paleoenvironments",
    year = "1982",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The Avalon tectonostratigraphic zone occupies about 25\% of the area of insular Newfoundland. Late Precambrian development of the Avalon terrane is distinctly different than that of other parts of the Appalachian orogen and cratonic North America. Late Precambrian volcanism and tectonic instability gave way to deposition of about 2 km of Cambrian and Lower Ordovician dominantly epiclastic sediments on a slowly subsiding, relatively stable shelf platform.The Lower Cambrian Random Formation is part of the platformal sequence and is bounded by regional disconformities over much of the Newfoundland Avalon Zone, except around Fortune Bay where it is underlain by older terrestrial and shallow-marine sediments. The Random Formation was deposited during a time of global sea-level rise, and consists of up to 250 m of shoreline, nearshore, and open-shelf deposits that record macrotidal conditions and periodic storm activity. Cross-bedded quartzarenites occur in units to about 50 m thick (one exceptional unit is 110 m thick) that tend to have gradational bases and abrupt tops. Bimodal–bipolar paleocurrent data are best explained by reversing tidal currents. These sandstone units show no evidence of intertidal (beach) processes and are therefore interpreted as subtidal ridges or shoals. The intertidal environment is represented by a shaly unit, with thin sandstone beds, that is characterized by flaser and lenticular bedding, oscillation (wave) ripples, some flat-topped ripples, and abundant synaeresis (dehydration) cracks. A muddy shoreline and subtidal sands suggest a macrotidal setting.Storm deposits range from: (1) fine, micaceous, red sandstones with fiat, gently dipping lamination, low-angle truncation surfaces, rare hummocks, shale-clast horizons, granule lags, and steep-sided erosional gulleys believed to represent lower shoreface rip-current channels; to (2) mudstones with graded, sole-marked, glauconitic sandstone beds deposited on an open shelf by storm-generated density currents.",
    url = "https://doi.org/10.1139/e82-180",
    doi = "10.1139/e82-180",
    number = "10",
    openalex = "W2021369906",
    pages = "2028-2042",
    volume = "19",
    references = "doi1010079783642814983, doi1010160025322767900564, doi1010160037073880900226, doi101086628416, doi101111j136530911977tb00134x, doi1011300016760619637493sitcio20co2, doi101139e79156, doi101306212f7e4b2b2411d78648000102c1865d, doi10130674d721442b2111d78648000102c1865d, openalexw2094255421"
}

@misc{clarke1985petroleum14,
    author = "Clarke, J. W",
    title = "Petroleum Geology of East Siberia, 85-367 of U.S. Geological Survey Open File Reports",
    year = "1985",
    howpublished = "Washington, DC, U.S. Geological Survey",
    note = "talkorigins\_source = {true}; raw\_reference = {Clarke, J. W., 1985, Petroleum Geology of East Siberia, 85-367 of U.S. Geological Survey Open File Reports: Washington, DC, U.S. Geological Survey.}"
}

@article{park1987middle,
    author = "Park, Byong-Kwon and Han, Sang-Joon",
    title = "Middle Cambrian Back-Reef Deposits: Carbonates Interbedded in the Lower Part of Pungchon Limestone Formation, Korea",
    year = "1987",
    journal = "Journal of the Geological Society of Korea",
    url = "https://doi.org/10.14770/jgsk.1987.23.4.287",
    doi = "10.14770/jgsk.1987.23.4.287",
    number = "4",
    openalex = "W7124454945",
    pages = "287-305",
    volume = "23"
}

@article{doi1010160037073888901339,
    author = "Miall, Andrew D.",
    title = "Architectural elements and bounding surfaces in fluvial deposits: anatomy of the Kayenta formation (lower jurassic), Southwest Colorado",
    year = "1988",
    journal = "Sedimentary Geology",
    url = "https://doi.org/10.1016/0037-0738(88)90133-9",
    doi = "10.1016/0037-0738(88)90133-9",
    openalex = "W1981723811",
    references = "doi1010029781444303773, doi1010160012825277900551, doi101016001282527990059x, doi1010160012825285900017, doi1010160037073869900104, doi1010160037073880900226, doi1010160037073883900763, doi1010160037073884900745, doi101111j136530911978tb00323x, doi10113000167606195364381tfsaci20co2, doi102110pec8739, openalexw1912927042"
}

Abstract Sections exposing the Cambrian–Ordovician Boundary interval at Broom Point in western Newfoundland have been proposed earlier for a global systemic boundary stratotype. These lie within the Cow Head Group, a late Middle Cambrian to early Middle Ordovician allochthonous unit of limestone, shale, and conglomerate deposited at the toe of the ancient continental slope and on the adjacent continental rise. Several recent studies have further investigated the stratigraphy, sedimentology, and palaeontology of the Cow Head Group and others are under way on magnetostratigraphy and chemostratigraphy. These aspects are reviewed for six key boundary sections representing proximal to distal facies: Cow Head Ledge, Broom Point South, Broom Point North, St Pauls Inlet Quarry, Martin Point, and Green Point. In particular, new data are presented from 260 conodont samples that yielded 15500 conodonts. This intense sampling has allowed the discrimination of minor hiatuses in the proximal to intermediate facies where conglomerates have eroded and cannibalized underlying strata. New conodont data from Broom Point North have lowered the base of the C. lindstromi Zone into unit 74 conglomerates, thereby making this section unsuitable as a boundary stratotype. New collections from Green Point have yielded abundant conodonts and over 9400 conodonts have been recovered from 77 samples. The conodont, graptolite, and trilobite biostratigraphy through the boundary interval is documented allowing accurate correlation between sections and more precisely revealing small hiatuses in the proximal and intermediate facies. The sequence of conodont zones is: Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedius, C. lindstromi and C. angulatus. These can be correlated with trilobite zones established from both in situ and clast faunas from the proximal to intermediate facies and with graptolite assemblages (of Cooper 1979) especially in the intermediate to distal facies. Three new species of Cordylodus are described (C. andresi, C. hastatus and C. tortus) and the full apparatus of Iapetognathus preaengensis is illustrated. The criteria for selecting a global boundary stratotype and point (GSSP) are reviewed in terms of the Cow Head sections. The Green Point section is shown to meet, and largely surpass, the prerequisites required of a stratotype. The Green Point section is proposed to be the global boundary stratotype with the base of the Ordovician System defined at the base of unit 23, which is the base of the Broom Point Member, Green Point Formation, at a level coincident with the base of the Cordylodus lindstromi Zone. In addition to an abundant and superbly preserved conodont fauna, this section preserves the best sequence of earliest planktic graptolites through a 40 m interval; the first nematophorous graptolites (of Assemblage 1) occur in unit 25, 6.9 m above the base of the C. lindstromi Zone. This level can be readily correlated into the proximal facies where both deep and shallow water trilobites (in situ and in clasts, respectively) show the base of the C. lindstromi Zone to lie within the Symphysurina brevispicata trilobite Subzone.

@article{doi101017s0016756800013042,
    author = "Barnes, Christopher R.",
    title = "The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada",
    year = "1988",
    journal = "Geological Magazine",
    abstract = "Abstract Sections exposing the Cambrian–Ordovician Boundary interval at Broom Point in western Newfoundland have been proposed earlier for a global systemic boundary stratotype. These lie within the Cow Head Group, a late Middle Cambrian to early Middle Ordovician allochthonous unit of limestone, shale, and conglomerate deposited at the toe of the ancient continental slope and on the adjacent continental rise. Several recent studies have further investigated the stratigraphy, sedimentology, and palaeontology of the Cow Head Group and others are under way on magnetostratigraphy and chemostratigraphy. These aspects are reviewed for six key boundary sections representing proximal to distal facies: Cow Head Ledge, Broom Point South, Broom Point North, St Pauls Inlet Quarry, Martin Point, and Green Point. In particular, new data are presented from 260 conodont samples that yielded 15500 conodonts. This intense sampling has allowed the discrimination of minor hiatuses in the proximal to intermediate facies where conglomerates have eroded and cannibalized underlying strata. New conodont data from Broom Point North have lowered the base of the C. lindstromi Zone into unit 74 conglomerates, thereby making this section unsuitable as a boundary stratotype. New collections from Green Point have yielded abundant conodonts and over 9400 conodonts have been recovered from 77 samples. The conodont, graptolite, and trilobite biostratigraphy through the boundary interval is documented allowing accurate correlation between sections and more precisely revealing small hiatuses in the proximal and intermediate facies. The sequence of conodont zones is: Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedius, C. lindstromi and C. angulatus. These can be correlated with trilobite zones established from both in situ and clast faunas from the proximal to intermediate facies and with graptolite assemblages (of Cooper 1979) especially in the intermediate to distal facies. Three new species of Cordylodus are described (C. andresi, C. hastatus and C. tortus) and the full apparatus of Iapetognathus preaengensis is illustrated. The criteria for selecting a global boundary stratotype and point (GSSP) are reviewed in terms of the Cow Head sections. The Green Point section is shown to meet, and largely surpass, the prerequisites required of a stratotype. The Green Point section is proposed to be the global boundary stratotype with the base of the Ordovician System defined at the base of unit 23, which is the base of the Broom Point Member, Green Point Formation, at a level coincident with the base of the Cordylodus lindstromi Zone. In addition to an abundant and superbly preserved conodont fauna, this section preserves the best sequence of earliest planktic graptolites through a 40 m interval; the first nematophorous graptolites (of Assemblage 1) occur in unit 25, 6.9 m above the base of the C. lindstromi Zone. This level can be readily correlated into the proximal facies where both deep and shallow water trilobites (in situ and in clasts, respectively) show the base of the C. lindstromi Zone to lie within the Symphysurina brevispicata trilobite Subzone.",
    url = "https://doi.org/10.1017/s0016756800013042",
    doi = "10.1017/s0016756800013042",
    openalex = "W2099144811",
    references = "doi104095125053, openalexw2207565996"
}

A rich assemblage of early Middle Cambrian brachiopods from the ‘first discovery limestone’ of the Coonigan Formation, western N.S.W. contains 20 taxa (eight Articulata, 11 Inarticulata and one which cannot be assigned with certainty to either class). New articulate species are Nisusia grandis grandis, N. grandis glabra, Wimanella tricavata, Arctohedra alata, Acareorthis jelli, Cymbricia spinicostata, Austrohedra mimica and Glaphyrorthis fastigata, with the last four mentioned new genera. Inarticulate taxa include species of Trematosia and?Kutorgina, Hadrotreta primaeva (Walcott), Micromitra nerranubawu Kruse and new species of Kleithriatreta lamellosa, Eothele granulata, Dictyonina australis, Palaeoschmidites horizontalis, Lingulella bynguanoensis, Westonia cymbricensis, and an indeterminate lingulacean; Kleithriatreta is a new genus. The enigmatic new genus and species Bynguanoia perplexa cannot be placed within either the Articulata or Inarticulata. Seven taxa are endemic, six are comparable with taxa from North America, and four with species from the U.S.S.R. The closest correlation, based on three species, is with the Pioche Shale, Nevada, which straddles the Early-Middle Cambrian boundary. The associated trilobite fauna with Redlichia and Pagetia indicates an earliest Middle Cambrian age.

@article{doi10108003115519008619059,
    author = "Roberts, John and Jell, Peter A.",
    title = "Early Middle Cambrian (Ordian) brachiopods of the Coonigan Formation, western New South Wales",
    year = "1990",
    journal = "Alcheringa An Australasian Journal of Palaeontology",
    abstract = "A rich assemblage of early Middle Cambrian brachiopods from the ‘first discovery limestone’ of the Coonigan Formation, western N.S.W. contains 20 taxa (eight Articulata, 11 Inarticulata and one which cannot be assigned with certainty to either class). New articulate species are Nisusia grandis grandis, N. grandis glabra, Wimanella tricavata, Arctohedra alata, Acareorthis jelli, Cymbricia spinicostata, Austrohedra mimica and Glaphyrorthis fastigata, with the last four mentioned new genera. Inarticulate taxa include species of Trematosia and?Kutorgina, Hadrotreta primaeva (Walcott), Micromitra nerranubawu Kruse and new species of Kleithriatreta lamellosa, Eothele granulata, Dictyonina australis, Palaeoschmidites horizontalis, Lingulella bynguanoensis, Westonia cymbricensis, and an indeterminate lingulacean; Kleithriatreta is a new genus. The enigmatic new genus and species Bynguanoia perplexa cannot be placed within either the Articulata or Inarticulata. Seven taxa are endemic, six are comparable with taxa from North America, and four with species from the U.S.S.R. The closest correlation, based on three species, is with the Pioche Shale, Nevada, which straddles the Early-Middle Cambrian boundary. The associated trilobite fauna with Redlichia and Pagetia indicates an earliest Middle Cambrian age.",
    url = "https://doi.org/10.1080/03115519008619059",
    doi = "10.1080/03115519008619059",
    openalex = "W2001653686",
    references = "doi105479si009638011395227, doi105962bhltitle5732, openalexw2598637701"
}

Acritarchs in the sedimentologically continuous, shallow-marine, Upper Vendian - Lower Cambrian subsurface sequence of the Lublin Slope, East European Platform (EEP), Poland are abundant and well-preserved. Forty-five form-species were recovered, and their taxonomic status is revised. Three new form-genera are erected. Asteridium n.gen. and Heliosphaeridium n. gen. include species with solid and hollow processes, respectively, previously referred to Micrhystridium Deflandre. Globosphaeridium n.gen. includes acritarchs with solid processes formerly attributed to Baltisphaeridium Eisenack. The genus Skiagia is emended. Microfossil preservation yields information on the thermal history of the Lublin basin. The acritarch succession in the Lublin Slope forms the basis for a new Lower Cambrian zonation, in ascending order the Asteridium tornaturn - Comasphaeridium velvetum, Skiagia ornata - Fimbriaglomerella membranacea, Heliosphaeridium dissimilare - Skiagia ciliosa, and Volkovia dentifera - Liepaina plana Assemblage-zones. A significant radiation at the upper part of the Włodawa Formation and within the Mazowsze Formation involves taxa of the Asteridiumtornatum - Comasphaeridium velvetum assemblage taken to mark the Pre cambrian-Cambrian boundary. The Kaplonosy IG-1 drillcore is proposed as reference section for the boundary. The Upper Vendian - Lower Cambrian biostratigraphy in Poland is revised. The Sabellidites-Vendotaenia Interval-zone is proposed, the range of the Platysolenites antiquissimus Zone is revised, and the Holmia kjerulfi Assemblage-zone is recognized. The Protolenus zone remains as an informal zone. Parts of the investigated sequence are correlated with the Schmidtiellus mickwitzi Zone elsewhere. The early Cambrian Mobergella Zone and the Klimontovian Stage are rejected. The Precambrian-Cambrian boundary is discussed in light of acritarch evidence from sequences in the East European, Baltoscandian, Siberian, South China and Avalon Platforms. The acritarch zone contemporaneous with the earliest trilobite zone in the Baltoscandian Platform and the EEP embraces part of the Tommotian and Meishucunian strata in Siberia and China. Units underlying the Tommotian in Siberia may be Cambrian. Lower Cambrian rocks of the EEP, the Baltoscandian Platform, and the Scandinavian Caledonides, are correlated on the basis of acritarchs.

@incollection{doi10182618200374742199101,
    author = "Moczydłowska, Małgorzata",
    title = "Acritarch biostratigraphy of the Lower Cambrian and the Precambrian-Cambrian boundary in southeastern Poland",
    year = "1991",
    booktitle = "Fossils and strata",
    abstract = "Acritarchs in the sedimentologically continuous, shallow-marine, Upper Vendian - Lower Cambrian subsurface sequence of the Lublin Slope, East European Platform (EEP), Poland are abundant and well-preserved. Forty-five form-species were recovered, and their taxonomic status is revised. Three new form-genera are erected. Asteridium n.gen. and Heliosphaeridium n. gen. include species with solid and hollow processes, respectively, previously referred to Micrhystridium Deflandre. Globosphaeridium n.gen. includes acritarchs with solid processes formerly attributed to Baltisphaeridium Eisenack. The genus Skiagia is emended. Microfossil preservation yields information on the thermal history of the Lublin basin. The acritarch succession in the Lublin Slope forms the basis for a new Lower Cambrian zonation, in ascending order the Asteridium tornaturn - Comasphaeridium velvetum, Skiagia ornata - Fimbriaglomerella membranacea, Heliosphaeridium dissimilare - Skiagia ciliosa, and Volkovia dentifera - Liepaina plana Assemblage-zones. A significant radiation at the upper part of the Włodawa Formation and within the Mazowsze Formation involves taxa of the Asteridiumtornatum - Comasphaeridium velvetum assemblage taken to mark the Pre cambrian-Cambrian boundary. The Kaplonosy IG-1 drillcore is proposed as reference section for the boundary. The Upper Vendian - Lower Cambrian biostratigraphy in Poland is revised. The Sabellidites-Vendotaenia Interval-zone is proposed, the range of the Platysolenites antiquissimus Zone is revised, and the Holmia kjerulfi Assemblage-zone is recognized. The Protolenus zone remains as an informal zone. Parts of the investigated sequence are correlated with the Schmidtiellus mickwitzi Zone elsewhere. The early Cambrian Mobergella Zone and the Klimontovian Stage are rejected. The Precambrian-Cambrian boundary is discussed in light of acritarch evidence from sequences in the East European, Baltoscandian, Siberian, South China and Avalon Platforms. The acritarch zone contemporaneous with the earliest trilobite zone in the Baltoscandian Platform and the EEP embraces part of the Tommotian and Meishucunian strata in Siberia and China. Units underlying the Tommotian in Siberia may be Cambrian. Lower Cambrian rocks of the EEP, the Baltoscandian Platform, and the Scandinavian Caledonides, are correlated on the basis of acritarchs.",
    url = "https://doi.org/10.18261/8200374742-1991-01",
    doi = "10.18261/8200374742-1991-01",
    openalex = "W4385659530",
    references = "doi1010079783642964466, doi1010160012825272901316, doi1010160012825273900925, doi1010160016703784900899, doi1010160301926887900015, doi1010160301926887900441, doi1010160377839888900023, doi101017s0022336000036465, doi101017s0263593300010051, doi101038321832a0, doi101038333313a0, doi101038scientificamerican0779122, doi101073pnas492158, doi10108011035898209455245, doi101130001676061972831299peboto20co2, doi101139e83050, doi10182618200093301197301, doi1018814epiiugs1985v8i2003, doi1023071484559, doi1023071485622, doi1034194bullgguv1346676, nelson1978late, openalexw2026796374, openalexw2603635224, openalexw2753647789, openalexw353142951, schidlowski1988a, tappan1970geobiologic, vidal1985earths"
}

@article{doi1010160012821x94901783,
    author = "Derry, Louis A. and Brasier, Martin D. and Corfield, Richard M. and Rozanov, A. Yu. and Zhuravlev, Andrey Yu.",
    title = "Sr and C isotopes in Lower Cambrian carbonates from the Siberian craton: A paleoenvironmental record during the ‘Cambrian explosion’",
    year = "1994",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/0012-821x(94)90178-3",
    doi = "10.1016/0012-821x(94)90178-3",
    openalex = "W2042155317",
    references = "doi10100797814899242787"
}

The Lower Palaeozoic Haima Group of the Sultanate of Oman comprises a sequence dominated by siliciclastic rocks up to several kilometres thick and broadly divisible into two groups. The sequence is known in outline from subsurface exploration, but recent field work on outcrops in the isolated Huqf area in east-central Oman has allowed a more detailed environmental interpretation of the succession. At the base coarse continental deposits of the Lower Haima Group rest unconformably on Precambrian–Lower Cambrian Huqf Group sediments (mainly carbonates and evaporites). The overlying Upper Haima Group comprises from base to top the aeolian dominated Amin Formation, the non-marine (coastal plain) to shallow marine (intertidal–subtidal) sediments of the Andam Formation, the non-marine to marginally marine Ghudun Formation, and the complex cyclical deep to shallow water deposits of the Safiq Formation. Correlation of the Haima Group of Oman with the Lower Palaeozoic of the Arabian Peninsula, North Africa and Iran allows the evolution of the Gondwanan margin to be modelled. A widespread Lower Cambrian sequence of coarse alluvium, resting on peneplained Upper Precambrian–Infracambrian Huqf Group strata, represents the final stage of uplift and basin fill associated with the Late Proterozoic suturing of Arabia and adjacent plates which resulted in the formation of the Gondwanan continent. The overlying thick sequence of continental (fluvial and aeolian) sediments was deposited in a series of stable intracratonic basins across the Gondwanan landmass. In the Mid- and Late Cambrian an overall sea-level rise led to the repeated development of shallow marine shelf carbonates across the margin. The subsequent replacement of this marginal carbonate sequence with a thick marginal to non-marine, sand dominated sequence may reflect the interplay of several events: the drift of Gondwana towards more southerly latitudes, a phase of strong tectonic rejuvenation during the latest Cambrian–Early Ordovician, and/or a eustatic fall in sea-level. Organic-rich marine mudrocks were deposited over much of the Gondwanan platform during a series of marked eustatic sea-level rises during the Mid–Late Ordovician and Early Silurian. In Oman no evidence has yet been found for the significant Late Ordovician glacial event recorded from North Africa and Saudi Arabia.

@article{doi101144gsjgs15320213,
    author = "Millson, John A. and Mercadier, C. and Livera, S. E. and Peters, Jeroen M.",
    title = "The Lower Palaeozoic of Oman and its context in the evolution of a Gondwanan continental margin",
    year = "1996",
    journal = "Journal of the Geological Society",
    abstract = "The Lower Palaeozoic Haima Group of the Sultanate of Oman comprises a sequence dominated by siliciclastic rocks up to several kilometres thick and broadly divisible into two groups. The sequence is known in outline from subsurface exploration, but recent field work on outcrops in the isolated Huqf area in east-central Oman has allowed a more detailed environmental interpretation of the succession. At the base coarse continental deposits of the Lower Haima Group rest unconformably on Precambrian–Lower Cambrian Huqf Group sediments (mainly carbonates and evaporites). The overlying Upper Haima Group comprises from base to top the aeolian dominated Amin Formation, the non-marine (coastal plain) to shallow marine (intertidal–subtidal) sediments of the Andam Formation, the non-marine to marginally marine Ghudun Formation, and the complex cyclical deep to shallow water deposits of the Safiq Formation. Correlation of the Haima Group of Oman with the Lower Palaeozoic of the Arabian Peninsula, North Africa and Iran allows the evolution of the Gondwanan margin to be modelled. A widespread Lower Cambrian sequence of coarse alluvium, resting on peneplained Upper Precambrian–Infracambrian Huqf Group strata, represents the final stage of uplift and basin fill associated with the Late Proterozoic suturing of Arabia and adjacent plates which resulted in the formation of the Gondwanan continent. The overlying thick sequence of continental (fluvial and aeolian) sediments was deposited in a series of stable intracratonic basins across the Gondwanan landmass. In the Mid- and Late Cambrian an overall sea-level rise led to the repeated development of shallow marine shelf carbonates across the margin. The subsequent replacement of this marginal carbonate sequence with a thick marginal to non-marine, sand dominated sequence may reflect the interplay of several events: the drift of Gondwana towards more southerly latitudes, a phase of strong tectonic rejuvenation during the latest Cambrian–Early Ordovician, and/or a eustatic fall in sea-level. Organic-rich marine mudrocks were deposited over much of the Gondwanan platform during a series of marked eustatic sea-level rises during the Mid–Late Ordovician and Early Silurian. In Oman no evidence has yet been found for the significant Late Ordovician glacial event recorded from North Africa and Saudi Arabia.",
    url = "https://doi.org/10.1144/gsjgs.153.2.0213",
    doi = "10.1144/gsjgs.153.2.0213",
    openalex = "W1963803326",
    references = "doi101007978366201141664, doi101016003101829190142e, doi1010160191814191901105, doi101029tc004i005p00497, doi101111j174754571996tb00520x, doi101126science23547931156, doi10113000167606198596817pmaota20co2, doi1013065d25c4a516c111d78645000102c1865d, hiscott1982tidal, openalexw607793741, openalexw622751671"
}

The Mickwitzia sandstone, south-central Sweden, consists of about 10 m of Lower Cambrian clastic sediments deposited in an epicontinental setting. An in formal, lithologically based subdivision, A-E, is introduced. A thin basal conglomerate (interval A) is followed by thin-bedded sand and siltstone with c1ayey partings (interval B and D) and medium-grained sandstone (interval C), largely representing subtidal storm deposits. Interval E consists of thick-bedded shoreface deposits. Heterolithic intervals have well-preserved trace fossils, including Cruziana, Rusophycus, Gyrolithes, Treptichnus and Teichichnus. Beds with impure, often weakly cemented sandstone (interval C) have Rhizocorallium, Monocraterion and Skolithos. Trace fossils are dominated by infaunal feeding and feeding?-dwelling burrows; 40 ichnotaxa are recognized, representing the activity of but a few types of animals. The type material of Monocraterion tentaculatum Torell, 1870, is illustrated for the first time, and the relationship of Monocraterion to Skolithos and Rosselia is discussed. Previously poorly known taxa are described. Scotolithus mirabilis Linnarsson, 1871, consists of a vertical shaft which in its lower part diverges into a wide broom-shaped arrangement. Spiroscolex spiralis (Torell, 1870) is a little-used name for burrows identical to Gyrolithes polonicus. Halopoa imbricata Torell, 1870, is a burrow related to Palaeophycus sulcatus, with a morphology dependant on sediment consistency: it is here assigned to Palaeophycus imbricatus. Fraena tenella Linnarsson, 1871, is assigned to Cruziana and considered a subjective senior synonym of Cruziana problematica. Phycodes pedum Seilacher, 1955, should be assigned to Treptichnus.

@incollection{doi10182618200376656199701,
    author = "Jensen, Sören",
    title = "Trace fossils from the Lower Cambrian Mickwitzia sandstone, south-central Sweden",
    year = "1997",
    booktitle = "Fossils and strata",
    abstract = "The Mickwitzia sandstone, south-central Sweden, consists of about 10 m of Lower Cambrian clastic sediments deposited in an epicontinental setting. An in formal, lithologically based subdivision, A-E, is introduced. A thin basal conglomerate (interval A) is followed by thin-bedded sand and siltstone with c1ayey partings (interval B and D) and medium-grained sandstone (interval C), largely representing subtidal storm deposits. Interval E consists of thick-bedded shoreface deposits. Heterolithic intervals have well-preserved trace fossils, including Cruziana, Rusophycus, Gyrolithes, Treptichnus and Teichichnus. Beds with impure, often weakly cemented sandstone (interval C) have Rhizocorallium, Monocraterion and Skolithos. Trace fossils are dominated by infaunal feeding and feeding?-dwelling burrows; 40 ichnotaxa are recognized, representing the activity of but a few types of animals. The type material of Monocraterion tentaculatum Torell, 1870, is illustrated for the first time, and the relationship of Monocraterion to Skolithos and Rosselia is discussed. Previously poorly known taxa are described. Scotolithus mirabilis Linnarsson, 1871, consists of a vertical shaft which in its lower part diverges into a wide broom-shaped arrangement. Spiroscolex spiralis (Torell, 1870) is a little-used name for burrows identical to Gyrolithes polonicus. Halopoa imbricata Torell, 1870, is a burrow related to Palaeophycus sulcatus, with a morphology dependant on sediment consistency: it is here assigned to Palaeophycus imbricatus. Fraena tenella Linnarsson, 1871, is assigned to Cruziana and considered a subjective senior synonym of Cruziana problematica. Phycodes pedum Seilacher, 1955, should be assigned to Treptichnus.",
    url = "https://doi.org/10.18261/8200376656-1997-01",
    doi = "10.18261/8200376656-1997-01",
    openalex = "W4385643405",
    references = "bridge1985unusual, doi10100797814757131762, doi1010160012825283900223, doi1010160025322767900515, doi1010160031018279901123, doi1010160037073884900034, doi1010160191814182900463, doi10108003115518908527821, doi101111j136530911977tb00134x, doi101111j150239311969tb01258x, doi101111j150239311980tb00632x, doi101126science22246281123, doi10113000167606198293663hssoiv20co2, doi101139e87124, doi101306212f7e4b2b2411d78648000102c1865d, doi101306212f89c22b2411d78648000102c1865d, doi10182618200049639197506, doi10182618200093301197301, doi10182618200374254198901, doi10182618200374742199101, doi1023073514911, doi105281zenodo15992748, doi105860choice304422, openalexw2344228935, openalexw2603635224, openalexw3116078484, openalexw3126336940, openalexw353142951, openalexw574363047, roberts1982facies"
}

Many trilobite species of the order Agnostida have short stratigraphic ranges and global distribution in open-marine deposits. They are most abundant and most diverse from about the middle Middle Cambrian to the middle Upper Cambrian where they are proving to be excellent biostratigraphic indices. We describe unusually rich agnostoid faunas of that age from two thick, well-exposed sections, one near Paibi and one near Wangcun, in northwestern Hunan Province, China. All collections are from the Huaqiao Formation, the definition of which is revised and its stratigraphic content is expanded. Most of the fossils are well preserved in dark, laminated, argillaceous carbonates that were deposited in lower slope environments. These are assigned to 76 species and 33 genera. New species described are Agnostus? babcocki, Ammagnostus? cryptus, Ammagnostus histus, Ammagnostus hunanensis, Ammagnostus wangcunensis, Baltagnostus? ambonus, Linguagnostus stenus, Lisogoragnostus hybus, Lisogoragnostus mictus, and Utagnostus songae. Species reassigned in a new generic combination are Ammagnostus laiwuensis (Lorenz, 1906), Glaberagnostus? cicer (Tullberg, 1880), Kormagnostus minutus (Schrank, 1975), and Pseudophalacroma scanense (Westergård, 1946). The subfamily Ammagnostinae Öpik, 1967, is elevated to family rank.The bases of eight agnostoid biozones are defined by the lowest occurrence of a common species having a relatively short stratigraphic range and wide geographic distribution. In ascending order, these zones are named for Ptychagnostus atavus, Ptychagnostus punctuosus, Goniagnostus nathorsti, Lejopyge laevigata, Proagnostus bulbus, Linguagnostus reconditus, Glyptagnostus stolidotus, and Glyptagnostus reticulatus. Each zone is further characterized by an assemblage of agnostoid species that may vary from place to place. By extrapolating from recently published uranium-lead geochronology, we estimate that the average duration of these agnostoid zones was approximately one million years.Formal division of the Cambrian System into global series and stages is a current project of the International Subcommission on Cambrian Stratigraphy. If the base of an upper Cambrian series of whatever name is selected to correlate closely with the traditional Middle–Upper Cambrian boundary in Europe, we propose the base of the Linguagnostus reconditus Zone in the Wangcun section as a potential Global Standard Stratotype-section and Point (GSSP). Alternatively, if the base of an upper Cambrian series is selected to coincide with the base of the Glyptagnostus reticulatus Zone, we propose the base of that zone in the Paibi section as a potential GSSP.

@article{doi101666002233602000531abatmc20co2,
    author = "Peng, Shanchi and Robison, Richard A.",
    title = "AGNOSTOID BIOSTRATIGRAPHY ACROSS THE MIDDLE–UPPER CAMBRIAN BOUNDARY IN HUNAN, CHINA",
    year = "2000",
    journal = "Journal of Paleontology",
    abstract = "Many trilobite species of the order Agnostida have short stratigraphic ranges and global distribution in open-marine deposits. They are most abundant and most diverse from about the middle Middle Cambrian to the middle Upper Cambrian where they are proving to be excellent biostratigraphic indices. We describe unusually rich agnostoid faunas of that age from two thick, well-exposed sections, one near Paibi and one near Wangcun, in northwestern Hunan Province, China. All collections are from the Huaqiao Formation, the definition of which is revised and its stratigraphic content is expanded. Most of the fossils are well preserved in dark, laminated, argillaceous carbonates that were deposited in lower slope environments. These are assigned to 76 species and 33 genera. New species described are Agnostus? babcocki, Ammagnostus? cryptus, Ammagnostus histus, Ammagnostus hunanensis, Ammagnostus wangcunensis, Baltagnostus? ambonus, Linguagnostus stenus, Lisogoragnostus hybus, Lisogoragnostus mictus, and Utagnostus songae. Species reassigned in a new generic combination are Ammagnostus laiwuensis (Lorenz, 1906), Glaberagnostus? cicer (Tullberg, 1880), Kormagnostus minutus (Schrank, 1975), and Pseudophalacroma scanense (Westergård, 1946). The subfamily Ammagnostinae Öpik, 1967, is elevated to family rank.The bases of eight agnostoid biozones are defined by the lowest occurrence of a common species having a relatively short stratigraphic range and wide geographic distribution. In ascending order, these zones are named for Ptychagnostus atavus, Ptychagnostus punctuosus, Goniagnostus nathorsti, Lejopyge laevigata, Proagnostus bulbus, Linguagnostus reconditus, Glyptagnostus stolidotus, and Glyptagnostus reticulatus. Each zone is further characterized by an assemblage of agnostoid species that may vary from place to place. By extrapolating from recently published uranium-lead geochronology, we estimate that the average duration of these agnostoid zones was approximately one million years.Formal division of the Cambrian System into global series and stages is a current project of the International Subcommission on Cambrian Stratigraphy. If the base of an upper Cambrian series of whatever name is selected to correlate closely with the traditional Middle–Upper Cambrian boundary in Europe, we propose the base of the Linguagnostus reconditus Zone in the Wangcun section as a potential Global Standard Stratotype-section and Point (GSSP). Alternatively, if the base of an upper Cambrian series is selected to coincide with the base of the Glyptagnostus reticulatus Zone, we propose the base of that zone in the Paibi section as a potential GSSP.",
    url = "https://doi.org/10.1666/0022-3360(2000)53[1:abatmc]2.0.co;2",
    doi = "10.1666/0022-3360(2000)53[1:abatmc]2.0.co;2",
    openalex = "W2174246195",
    references = "doi10182618200376583199501, doi1023072421322, openalexw1553396379"
}

ABSTRACT: Sandstone tempestite beds in the Starshot Formation, cen-tral Transantarctic Mountains, were deposited in a range of shoreline to shelf environments. Detailed sedimentological analysis indicates that these beds were largely deposited by wave-modified turbidity currents. These currents are types of combined flows in which storm-generated waves overprint flows driven by excess-weight forces. The interpreta-tion of the tempestites of the Starshot Formation as wave-dominated turbidites rests on multiple criteria. First, the beds are generally well graded and contain Bouma-like sequences. Like many turbidites, the soles display abundant well-developed flutes. They also contain thick divisions of climbing-ripple lamination. The lamination, however, is dominated by convex-up and sigmoidal foresets, which are geometries identical to those produced experimentally in current-dominated com-bined flows in clear water. Finally, paleocurrent data support a tur-bidity-current component of flow. Asymmetric folds in abundant con-

@article{doi101306022102720641,
    author = "Myrow, Paul M. and Fischer, Woodward W. and Goodge, John W.",
    title = "Wave-Modified Turbidites: Combined-Flow Shoreline and Shelf Deposits, Cambrian, Antarctica",
    year = "2002",
    journal = "Journal of Sedimentary Research",
    abstract = "ABSTRACT: Sandstone tempestite beds in the Starshot Formation, cen-tral Transantarctic Mountains, were deposited in a range of shoreline to shelf environments. Detailed sedimentological analysis indicates that these beds were largely deposited by wave-modified turbidity currents. These currents are types of combined flows in which storm-generated waves overprint flows driven by excess-weight forces. The interpreta-tion of the tempestites of the Starshot Formation as wave-dominated turbidites rests on multiple criteria. First, the beds are generally well graded and contain Bouma-like sequences. Like many turbidites, the soles display abundant well-developed flutes. They also contain thick divisions of climbing-ripple lamination. The lamination, however, is dominated by convex-up and sigmoidal foresets, which are geometries identical to those produced experimentally in current-dominated com-bined flows in clear water. Finally, paleocurrent data support a tur-bidity-current component of flow. Asymmetric folds in abundant con-",
    url = "https://doi.org/10.1306/022102720641",
    doi = "10.1306/022102720641",
    openalex = "W2151001842",
    references = "doi101111j136530911977tb00134x, doi10113000167606198293663hssoiv20co2, doi101139e79156"
}

Bioturbation long has been `blamed ' for eliminating late Proterozoic-style sedimentary structures and fabrics. While the presence of diverse and complex burrows in lowermost Cambrian strata is indisputable, analysis of Precambrian± Cambrian successions in southeast Newfoundland demon-strate that this burrowing style did not produce typical Phanerozoic-style ichnofabrics. Three hundred meters of the siltstone/sandstone facies of member 2 of the Chapel Island Formation were examined in the area of the Precambrian±Cambrian boundary stra-totype. Gyrolithes, Planolites, and Skolithos occur as sand in®lls ubiquitously throughout siltstone beds, most com-monly without direct contact with an overlying sandstone bed, as if ``¯oating' ' in the siltstone. In contrast, Treptichnus pedum occurs as sand in®lls adhering onto the base of thin sandstone beds that have different grain size and texture than the burrow in®lls. Both of these burrow types repre-sent a style of preservation in which the burrows are unat-tached to an overlying bed of the casting sediment. These styles of preservation occur frequently in the Treptichnus pedum Zone and continue into the Rusophycus avalonen-sis Zone in spite of an increase in trace fossil diversity. The sandstone beds are bioturbated only very rarely. The resul-tant fabric produced by ¯oating and, in particular, adher-ing burrows in these shallow marine deposits appears to be characteristic of many Lower Cambrian rocks. Silt layers appear to have been ®rm enough to have supported open burrows, likely as a result of a negligible mixed layer. This line of reasoning would predict that preservation of this type would be uncommon in younger strata deposited in open marine settings.

@article{doi1016690883135120020170003lciftc20co2,
    author = "Droser, Mary L. and Jensen, Sören and Gehlîng, James G. and Myrow, Paul M. and Narbonne, Guy M.",
    title = "Lowermost Cambrian Ichnofabrics from the Chapel Island Formation, Newfoundland: Implications for Cambrian Substrates",
    year = "2002",
    journal = "Palaios",
    abstract = "Bioturbation long has been `blamed \' for eliminating late Proterozoic-style sedimentary structures and fabrics. While the presence of diverse and complex burrows in lowermost Cambrian strata is indisputable, analysis of Precambrian± Cambrian successions in southeast Newfoundland demon-strate that this burrowing style did not produce typical Phanerozoic-style ichnofabrics. Three hundred meters of the siltstone/sandstone facies of member 2 of the Chapel Island Formation were examined in the area of the Precambrian±Cambrian boundary stra-totype. Gyrolithes, Planolites, and Skolithos occur as sand in®lls ubiquitously throughout siltstone beds, most com-monly without direct contact with an overlying sandstone bed, as if ``¯oating\' \' in the siltstone. In contrast, Treptichnus pedum occurs as sand in®lls adhering onto the base of thin sandstone beds that have different grain size and texture than the burrow in®lls. Both of these burrow types repre-sent a style of preservation in which the burrows are unat-tached to an overlying bed of the casting sediment. These styles of preservation occur frequently in the Treptichnus pedum Zone and continue into the Rusophycus avalonen-sis Zone in spite of an increase in trace fossil diversity. The sandstone beds are bioturbated only very rarely. The resul-tant fabric produced by ¯oating and, in particular, adher-ing burrows in these shallow marine deposits appears to be characteristic of many Lower Cambrian rocks. Silt layers appear to have been ®rm enough to have supported open burrows, likely as a result of a negligible mixed layer. This line of reasoning would predict that preservation of this type would be uncommon in younger strata deposited in open marine settings.",
    url = "https://doi.org/10.1669/0883-1351(2002)017<0003:lciftc>2.0.co;2",
    doi = "10.1669/0883-1351(2002)017<0003:lciftc>2.0.co;2",
    openalex = "W2147365606",
    references = "doi101038141548c0, doi1010970001069419650700000019, doi101111j150239311988tb02083x, doi1011300091761319940220179pcbgsr23co2, doi1011300091761319970251047wsmmss23co2, doi101139e87124, doi1023073515360, doi1023073515363, hiscott1982tidal, openalexw2344228935, openalexw2606050730"
}

Shallow-marine, siliciclastic depositional systems are dom-inated by physical sedimentary processes, with penecon-temporaneous cementation playing only a minor role in sed-iment dynamics. For this reason, microbial mats rarely form stromatolites in siliciclastic environments; instead, mats are preserved as wrinkle structures on bedding sur-faces. Microbial mat signatures should be widespread in silici-clastic rocks deposited before the Cambrian Period; howev-er, siliciclastic shelf successions of the upper Neoproterozoic Nudaus Formation, Nama Group, Namibia, contain only sparsely distributed wrinkle structures. The facies distri-bution of observed structures reflects the superposition of a taphonomic window of mat preservation on the ecological window of mat development. Mat colonization is favored by

@article{doi1016690883135120020170533scotfa20co2,
    author = "Noffke, Nora and Knoll, Andrew H. and Grotzinger, J. P.",
    title = "Sedimentary Controls on the Formation and Preservation of Microbial Mats in Siliciclastic Deposits: A Case Study from the Upper Neoproterozoic Nama Group, Namibia",
    year = "2002",
    journal = "Palaios",
    abstract = "Shallow-marine, siliciclastic depositional systems are dom-inated by physical sedimentary processes, with penecon-temporaneous cementation playing only a minor role in sed-iment dynamics. For this reason, microbial mats rarely form stromatolites in siliciclastic environments; instead, mats are preserved as wrinkle structures on bedding sur-faces. Microbial mat signatures should be widespread in silici-clastic rocks deposited before the Cambrian Period; howev-er, siliciclastic shelf successions of the upper Neoproterozoic Nudaus Formation, Nama Group, Namibia, contain only sparsely distributed wrinkle structures. The facies distri-bution of observed structures reflects the superposition of a taphonomic window of mat preservation on the ecological window of mat development. Mat colonization is favored by",
    url = "https://doi.org/10.1669/0883-1351(2002)017<0533:scotfa>2.0.co;2",
    doi = "10.1669/0883-1351(2002)017<0533:scotfa>2.0.co;2",
    openalex = "W2168528661",
    references = "doi101046j13653091200000284x, doi1023073515362"
}

@inproceedings{astafieva2003biomorphic,
    author = "Astafieva, Marina M.",
    title = "Biomorphic microstructures in the Sinsk formation (Lower Cambrian of the Siberian platform)",
    year = "2003",
    booktitle = "SPIE Proceedings",
    url = "https://doi.org/10.1117/12.486697",
    doi = "10.1117/12.486697",
    pages = "93",
    volume = "4939"
}

@article{doi101016s089598110300097x,
    author = "Buatois, Luís A. and Mángano, M. Gabriela",
    title = "Sedimentary facies, depositional evolution of the Upper Cambrian–Lower Ordovician Santa Rosita formation in northwest Argentina",
    year = "2003",
    journal = "Journal of South American Earth Sciences",
    url = "https://doi.org/10.1016/s0895-9811(03)00097-x",
    doi = "10.1016/s0895-9811(03)00097-x",
    openalex = "W2021275366",
    references = "doi101016003192018990263x, doi1010970001069419650700000019, doi10113000167606198293663hssoiv20co2, doi1011300016760619881001704tosb23co2, doi1011300091761319808543ncrihs20co2, doi101306c1ea47bb16c911d78645000102c1865d, doi101306d4267a692b2611d78648000102c1865d, doi102110csp9907, doi104067s071602082000000200006, doi105860choice285664, hiscott1982tidal"
}

The Campanario Formation is the middle unit of the upper Lower to Middle Cambrian Mesón Group of northwest Argentina. This formation is interpreted as having accumulated in macrotidal shallow-marine environments with extensive tidal-flat areas flanked seawards by subtidal sandbar complexes. Shallow subtidal and intertidal sand-flat deposits are dominated by vertical domiciles of suspension feeders and passive predators of the Skolithos ichnofacies (Skolithos, Arenicolites, Diplocraterion). The ichnogenus Syringomorphaz also occurs in sand-flat facies, commonly forming high-density, monospecific assemblages. Mixed-flat deposits contain hurizontal feeding, locomotion and resting traces as diagnostic components. A relatively low-diversity Cruziana ichnofacies is present in these lower-energy deposits. This ichnofauna includes presurned trilobite trace fossils (Cruziana, Rusophycus, Diplichnites), structures produced by sessile cnidarians (Bergaueria cf. B. perata) and shallow burrows and trails of vermiform organisms (Planolites, Palaeophycus, Helminthoidichnites). Tiering in these tidal-flat deposits is relatively simple. Six ichnoguilds (Cruziana problematica, Palaeophycus, Bergaueria, Rusophycus leifeirikssoni, Syringomorpha and Skolithos) have been defined. These ichnoguilds show a preferential palaeoenvironmental distribution following proximal-distal trends. Modern tidal flats are characterised by an abundant food supply derived from multiple sources, including nutrients brought in by the sea, terrestrially derived organic detritus and autochthonous food productian (e.g. primary production, faecal pellets). The inhabitants of modern intertidal areas are exposed to a double set of predators. During submergence they are preyed on by marine organisms and during emergence they are visited by enemies from the land and air. Contrastingly, the Cambrian intertidal environments functioned as refugia in the absence of continental (i.e. air and land) predators. Despite the physical stress, Cambrian tidal flats must have been protected areas where abundant food was available at almost no risk. Due to the paucity of land vegetation (and land-derived detritus), Cambrian intertidal trophic webs were almost entirely based on the organically rich marine source and most likely a significant autochthonous production. Although the picture that emerges from the Cambrian is qualitatively different, Cambrian tidal flats may have resembled modern ones in their ecological role as sites of reproductian and protection. The depth and extent of bioturbation reveal colonisation of a relatively deep in faunal ecospace by coelomate metazoans. Arthropod incursions in Cambrian tidal flats support an early colonisation of intertidal environments and indicate that representatives of the Cambrian evolutionary fauna were able to colonise very shallow-water environments, thus suggesting a significant landward expansion of the Cambrian explosion and the "Agronomic Revolution".

@incollection{doi10182619781405169851200402,
    author = "Mángano, M. Gabriela and Buatois, Luís A.",
    title = "Reconstructing Early Phanerozoic intertidal ecosystems: ichnology of the Cambrian Campanario Formation in northwest Argentina",
    year = "2004",
    booktitle = "Fossils and strata",
    abstract = {The Campanario Formation is the middle unit of the upper Lower to Middle Cambrian Mesón Group of northwest Argentina. This formation is interpreted as having accumulated in macrotidal shallow-marine environments with extensive tidal-flat areas flanked seawards by subtidal sandbar complexes. Shallow subtidal and intertidal sand-flat deposits are dominated by vertical domiciles of suspension feeders and passive predators of the Skolithos ichnofacies (Skolithos, Arenicolites, Diplocraterion). The ichnogenus Syringomorphaz also occurs in sand-flat facies, commonly forming high-density, monospecific assemblages. Mixed-flat deposits contain hurizontal feeding, locomotion and resting traces as diagnostic components. A relatively low-diversity Cruziana ichnofacies is present in these lower-energy deposits. This ichnofauna includes presurned trilobite trace fossils (Cruziana, Rusophycus, Diplichnites), structures produced by sessile cnidarians (Bergaueria cf. B. perata) and shallow burrows and trails of vermiform organisms (Planolites, Palaeophycus, Helminthoidichnites). Tiering in these tidal-flat deposits is relatively simple. Six ichnoguilds (Cruziana problematica, Palaeophycus, Bergaueria, Rusophycus leifeirikssoni, Syringomorpha and Skolithos) have been defined. These ichnoguilds show a preferential palaeoenvironmental distribution following proximal-distal trends. Modern tidal flats are characterised by an abundant food supply derived from multiple sources, including nutrients brought in by the sea, terrestrially derived organic detritus and autochthonous food productian (e.g. primary production, faecal pellets). The inhabitants of modern intertidal areas are exposed to a double set of predators. During submergence they are preyed on by marine organisms and during emergence they are visited by enemies from the land and air. Contrastingly, the Cambrian intertidal environments functioned as refugia in the absence of continental (i.e. air and land) predators. Despite the physical stress, Cambrian tidal flats must have been protected areas where abundant food was available at almost no risk. Due to the paucity of land vegetation (and land-derived detritus), Cambrian intertidal trophic webs were almost entirely based on the organically rich marine source and most likely a significant autochthonous production. Although the picture that emerges from the Cambrian is qualitatively different, Cambrian tidal flats may have resembled modern ones in their ecological role as sites of reproductian and protection. The depth and extent of bioturbation reveal colonisation of a relatively deep in faunal ecospace by coelomate metazoans. Arthropod incursions in Cambrian tidal flats support an early colonisation of intertidal environments and indicate that representatives of the Cambrian evolutionary fauna were able to colonise very shallow-water environments, thus suggesting a significant landward expansion of the Cambrian explosion and the "Agronomic Revolution".},
    url = "https://doi.org/10.18261/9781405169851-2004-02",
    doi = "10.18261/9781405169851-2004-02",
    openalex = "W4379417387",
    references = "doi101016s089598110300097x"
}

A diverse mollusc fauna from the Bastion Formation (Early Cambrian, middle Dyeran Stage) of North-East Greenland includes fifteen species (thirteen helcionelloids and two bivalves), adding considerable detail to the known fossil record of Early Cambrian molluscs from Laurentia. The occurrence of secondarily phosphatized shell surfaces together with phosphatic internal moulds in acid resistant residues allows new morphological details to be observed in several taxa. The fauna shows affinity to contemporaneous faunas from the Taconic allochthon of the eastern United States, but also to mollusc faunas of South Australia, China and Europe. The following new helcionelloid taxa are described: Capitoconus inclinatus n. gen. and n. sp. Capitoconus artus n. sp., Figurina groenlandica n. sp. and Latouchella ostenfeldense n. sp.

@article{doi1037570bgsd20045102,
    author = "Skovsted, Christian B.",
    title = "Mollusc fauna of the Early Cambrian Bastion Formation of North-East Greenland",
    year = "2004",
    journal = "Bulletin of the Geological Society of Denmark",
    abstract = "A diverse mollusc fauna from the Bastion Formation (Early Cambrian, middle Dyeran Stage) of North-East Greenland includes fifteen species (thirteen helcionelloids and two bivalves), adding considerable detail to the known fossil record of Early Cambrian molluscs from Laurentia. The occurrence of secondarily phosphatized shell surfaces together with phosphatic internal moulds in acid resistant residues allows new morphological details to be observed in several taxa. The fauna shows affinity to contemporaneous faunas from the Taconic allochthon of the eastern United States, but also to mollusc faunas of South Australia, China and Europe. The following new helcionelloid taxa are described: Capitoconus inclinatus n. gen. and n. sp. Capitoconus artus n. sp., Figurina groenlandica n. sp. and Latouchella ostenfeldense n. sp.",
    url = "https://doi.org/10.37570/bgsd-2004-51-02",
    doi = "10.37570/bgsd-2004-51-02",
    openalex = "W2124707132",
    references = "doi105479si009638011395227"
}

Abstract. The lower fine-grained interval of the Alfarcito Member of the Upper Cambrian-Tremadocian Santa Rosita Formation in northwestern Argentina represents an overall transgressive-regressive cycle, recording the establishment of an open-marine, shallow, low-gradient platform. Four main sedimentary facies have been recognized, environmentally ranging from the lower offshore to the lower/middle shoreface. Alternating and contrasting energy conditions due to repeated storm events superimposed on fairweather sediments were among the key controlling factors for trace fossil distribution and preservation. Fairweather and storm-related trace fossil assemblages are recognized. The first is the most diverse and includes the more varied behavioral strategies, such as locomotion (Archaeonassa fossulata, Cruziana semiplicata, C. problematica, Cruziana isp. and Diplichnites isp.); resting (Rusophycus moyensis, R. carbonarius, Rusophycus issp. and Bergaueria aff. B. hemispherica); pascichnia (Dimorphichnus aff. D. quadrifidus); feeding (Arthrophycus minimus,?Gyrolithes isp., Gyrophyllites isp.,?Phycodes isp. and Planolites reinecki); and dwelling (Palaeophycus tubularis, P. striatus). This assemblage represents the Cruziana ichnofacies. The storm-related assemblage is monospecific and includes vertical dwelling traces (Skolithos linearis), and is attributed to the Skolithos ichnofacies. Integration of ichnologic and sedimentologic data allows proximal-distal trends in shallow-marine trace fossil assemblages along a nearshore-offshore transect to be reconstructed. High-energy conditions prevailed in lower and middle shoreface environments and bioturbation is restricted to vertical burrows (Skolithos linearis), recording colonization after storm events. Environmental conditions in the offshore transition and the upper offshore are more variable and reflect the alternation of high-energy storm events and low-energy fairweather mudstone deposition. The storm-related Skolithos ichnofacies is present, but alternates with the faiweather assemblage (Cruziana ichnofacies) that reaches a diversity maximum in the upper offshore. Trace fossils are scarce in lower offshore deposits, being restricted to a few non-descript burrows, mostly Palaeophycus tubularis. Shoreface deposits from the Alfarcito Member compare favorably with the strongly stormdominated type. All these deposits are stacked to form regional coarsening-upward parasequences that record short-term progradational episodes separated by drowning surfaces. Vertical distribution of trace fossils parallels changes in stratal stacking patterns. Several ichnotaxa (especially Cruziana semiplicata, Rusophycus moyensis and Arthrophycus minimus) have biostratigraphic implications. Resumen. ICNOLOGIA DELMIEMBRO ALFARCITO (FORMACION SANTA ROSITA) DEL NOROESTE DE ARGENTINA: INTERACCIONES SUSTRATO-ANIMAL EN UN MAR SOMERO DEL PALEOZOICO INFERIOR DOMINADO POR OLEAJE. El intervalo inferior de grano fino del Miembro Alfarcito de la Formacion Santa Rosita (Cambrico Superior-Tremadociano) representa un ciclo general transgresivo-regresivo, registrando el establecimiento de una plataforma marina somera de bajo gradiente. Se reconocieron cuatro facies sedimentarias principales, cuyos ambientes varian entre costa-afuera bajo y shoreface bajo a medio. Entre los factores claves que controlaron la distribucion de los icnofosiles y su preservacion se encuentran las condiciones de energia alternantes y contrastantes debidas a eventos de tormenta repetidos superpuestos sobre sedimentos de buen tiempo. Se reconocieron asociaciones de trazas fosiles de buen tiempo y de tormenta. La primera es la mas diversa e incluye la mayor variacion de estrategias de comportamiento, tales como locomocion (Archaeonassa fossulata, Cruziana semiplicata, C. problematica, Cruziana isp. y Diplichnites isp.); reposo (Rusophycus moyensis, R. carbonarius, Rusophycus issp. y Bergaueria aff. B. hemispherica); pascichnia (Dimorphichnus aff. D. quadrifidus); alimentacion (Arthrophycus minimus,?Gyrolithes isp., Gyrophyllites isp.,?Phycodes isp. y Planolites reinecki); y habitacion en dos ocasiones (Palaeophycus tubularis, P. striatus). Esta asociacion representa la icnofacies de Cruziana. La asociacion relacionada con tormentas es monoespecifica e incluye trazas de alojamiento vertical (Skolithos linearis), y se atribuye a la icnofacies de Skolithos. La integracion de los datos icnologicos y sedimentologicos permite reconstruir las tendencias proximal-distales en las asociaciones de trazas fosiles marinas a lo largo de una transecta nearshore-offshore. En los ambientes de shoreface inferior y medio prevalecieron condiciones de alta energia y la bioturbacion se halla restringida a excavaciones verticales (Skolithos linearis), registrando la colonizacion luego de los eventos de tormenta. Las condiciones ambientales en la transicion a costa afuera y en costa afuera superior son mas variables y reflejan la alternancia de eventos de tormenta de alta energia y depositacion de fangolitas de buen tiempo y baja energia. Se halla presente la icnofacies de Skolithos relacionada con tormentas, la que alterna con la asociacion de buen tiempo (icnofacies de Cruziana) que alcanza su maxima diversidad en el costa-afuera superior. Los icnofosiles son escasos en el offshore bajo, estando restringidos a unas pocas excavaciones, mayormente Palaeophycus tubularis. Los depositos de shoreface del Miembro Alfarcito se pueden comparar con los tipos fuertemente dominados por tormentas. Todos estos depositos forman parasecuencias granocrecientes que registran los cortos episodios progradacionales separados por superficies de inundacion. La distribucion vertical de las trazas fosiles acompana los cambios en los patrones de depositacion. Varios icnotaxones (especialmente Cruziana semiplicata, Rusophycus moyensis y Arthrophycus minimus) poseen interes bioestratigrafico.

@article{openalexw1827267192,
    author = "Mángano, M. Gabriela and Buatois, Luís A. and Guinea, Fernando Muñiz",
    title = "Ichnology of the Alfarcito Member (Santa Rosita Formation) of northwestern Argentina: animal-substrate interactions in a lower Paleozoic wave-dominated shallow sea",
    year = "2005",
    journal = "Ameghiniana",
    abstract = "Abstract. The lower fine-grained interval of the Alfarcito Member of the Upper Cambrian-Tremadocian Santa Rosita Formation in northwestern Argentina represents an overall transgressive-regressive cycle, recording the establishment of an open-marine, shallow, low-gradient platform. Four main sedimentary facies have been recognized, environmentally ranging from the lower offshore to the lower/middle shoreface. Alternating and contrasting energy conditions due to repeated storm events superimposed on fairweather sediments were among the key controlling factors for trace fossil distribution and preservation. Fairweather and storm-related trace fossil assemblages are recognized. The first is the most diverse and includes the more varied behavioral strategies, such as locomotion (Archaeonassa fossulata, Cruziana semiplicata, C. problematica, Cruziana isp. and Diplichnites isp.); resting (Rusophycus moyensis, R. carbonarius, Rusophycus issp. and Bergaueria aff. B. hemispherica); pascichnia (Dimorphichnus aff. D. quadrifidus); feeding (Arthrophycus minimus,?Gyrolithes isp., Gyrophyllites isp.,?Phycodes isp. and Planolites reinecki); and dwelling (Palaeophycus tubularis, P. striatus). This assemblage represents the Cruziana ichnofacies. The storm-related assemblage is monospecific and includes vertical dwelling traces (Skolithos linearis), and is attributed to the Skolithos ichnofacies. Integration of ichnologic and sedimentologic data allows proximal-distal trends in shallow-marine trace fossil assemblages along a nearshore-offshore transect to be reconstructed. High-energy conditions prevailed in lower and middle shoreface environments and bioturbation is restricted to vertical burrows (Skolithos linearis), recording colonization after storm events. Environmental conditions in the offshore transition and the upper offshore are more variable and reflect the alternation of high-energy storm events and low-energy fairweather mudstone deposition. The storm-related Skolithos ichnofacies is present, but alternates with the faiweather assemblage (Cruziana ichnofacies) that reaches a diversity maximum in the upper offshore. Trace fossils are scarce in lower offshore deposits, being restricted to a few non-descript burrows, mostly Palaeophycus tubularis. Shoreface deposits from the Alfarcito Member compare favorably with the strongly stormdominated type. All these deposits are stacked to form regional coarsening-upward parasequences that record short-term progradational episodes separated by drowning surfaces. Vertical distribution of trace fossils parallels changes in stratal stacking patterns. Several ichnotaxa (especially Cruziana semiplicata, Rusophycus moyensis and Arthrophycus minimus) have biostratigraphic implications. Resumen. ICNOLOGIA DELMIEMBRO ALFARCITO (FORMACION SANTA ROSITA) DEL NOROESTE DE ARGENTINA: INTERACCIONES SUSTRATO-ANIMAL EN UN MAR SOMERO DEL PALEOZOICO INFERIOR DOMINADO POR OLEAJE. El intervalo inferior de grano fino del Miembro Alfarcito de la Formacion Santa Rosita (Cambrico Superior-Tremadociano) representa un ciclo general transgresivo-regresivo, registrando el establecimiento de una plataforma marina somera de bajo gradiente. Se reconocieron cuatro facies sedimentarias principales, cuyos ambientes varian entre costa-afuera bajo y shoreface bajo a medio. Entre los factores claves que controlaron la distribucion de los icnofosiles y su preservacion se encuentran las condiciones de energia alternantes y contrastantes debidas a eventos de tormenta repetidos superpuestos sobre sedimentos de buen tiempo. Se reconocieron asociaciones de trazas fosiles de buen tiempo y de tormenta. La primera es la mas diversa e incluye la mayor variacion de estrategias de comportamiento, tales como locomocion (Archaeonassa fossulata, Cruziana semiplicata, C. problematica, Cruziana isp. y Diplichnites isp.); reposo (Rusophycus moyensis, R. carbonarius, Rusophycus issp. y Bergaueria aff. B. hemispherica); pascichnia (Dimorphichnus aff. D. quadrifidus); alimentacion (Arthrophycus minimus,?Gyrolithes isp., Gyrophyllites isp.,?Phycodes isp. y Planolites reinecki); y habitacion en dos ocasiones (Palaeophycus tubularis, P. striatus). Esta asociacion representa la icnofacies de Cruziana. La asociacion relacionada con tormentas es monoespecifica e incluye trazas de alojamiento vertical (Skolithos linearis), y se atribuye a la icnofacies de Skolithos. La integracion de los datos icnologicos y sedimentologicos permite reconstruir las tendencias proximal-distales en las asociaciones de trazas fosiles marinas a lo largo de una transecta nearshore-offshore. En los ambientes de shoreface inferior y medio prevalecieron condiciones de alta energia y la bioturbacion se halla restringida a excavaciones verticales (Skolithos linearis), registrando la colonizacion luego de los eventos de tormenta. Las condiciones ambientales en la transicion a costa afuera y en costa afuera superior son mas variables y reflejan la alternancia de eventos de tormenta de alta energia y depositacion de fangolitas de buen tiempo y baja energia. Se halla presente la icnofacies de Skolithos relacionada con tormentas, la que alterna con la asociacion de buen tiempo (icnofacies de Cruziana) que alcanza su maxima diversidad en el costa-afuera superior. Los icnofosiles son escasos en el offshore bajo, estando restringidos a unas pocas excavaciones, mayormente Palaeophycus tubularis. Los depositos de shoreface del Miembro Alfarcito se pueden comparar con los tipos fuertemente dominados por tormentas. Todos estos depositos forman parasecuencias granocrecientes que registran los cortos episodios progradacionales separados por superficies de inundacion. La distribucion vertical de las trazas fosiles acompana los cambios en los patrones de depositacion. Varios icnotaxones (especialmente Cruziana semiplicata, Rusophycus moyensis y Arthrophycus minimus) poseen interes bioestratigrafico.",
    openalex = "W1827267192",
    references = "doi101016s089598110300097x"
}

Abstract A fauna of brachiopods and small shelly fossils from the Lower Cambrian Harkless Formation of Esmeraldina County in southern Nevada is described. The brachiopod Kyrshabaktella sp. provides the first unequivocal record of lingulids in the Lower Cambrian of the Great Basin. The shells of Kyrshabaktella sp. are fragmentary, but otherwise well preserved and an acrotretid-like columnar shell structure is demonstrated. The phosphatic tubular fossil Hyolithellus insolitus is described from North America for the first time and Sphenothallus sp. provides the oldest record of this problematic genus in Laurentian strata. Other faunal elements include two additional linguliform brachiopods, echinoderm ossicles and sponge spicules.

@article{doi10108011035890601284327,
    author = "Skovsted, Christian B. and Holmer, Lars E.",
    title = "The Lower Cambrian brachiopod Kyrshabaktella and associated shelly fossils from the Harkless Formation, southern Nevada",
    year = "2006",
    journal = "GFF",
    abstract = "Abstract A fauna of brachiopods and small shelly fossils from the Lower Cambrian Harkless Formation of Esmeraldina County in southern Nevada is described. The brachiopod Kyrshabaktella sp. provides the first unequivocal record of lingulids in the Lower Cambrian of the Great Basin. The shells of Kyrshabaktella sp. are fragmentary, but otherwise well preserved and an acrotretid-like columnar shell structure is demonstrated. The phosphatic tubular fossil Hyolithellus insolitus is described from North America for the first time and Sphenothallus sp. provides the oldest record of this problematic genus in Laurentian strata. Other faunal elements include two additional linguliform brachiopods, echinoderm ossicles and sponge spicules.",
    url = "https://doi.org/10.1080/11035890601284327",
    doi = "10.1080/11035890601284327",
    openalex = "W2055796612",
    references = "doi101080037454809494387, doi101080037454809496570, doi103133pp483f, doi105479si009638011395227, doi105962bhltitle13172, doi105962bhltitle13182"
}

A diverse and well-preserved fauna of shelly fossils from the upper Lower Cambrian Bastion and Ella Island Formations of North-East Greenland contains more than 90 species. The fauna is the most diverse shelly fauna yet discovered in the Lower Cambrian of Laurentia and includes many fossils previously known only from other continental blocks. It enhances correlation of the North-East Greenland succession into Laurentia, most notably with the Browns Pond Formation of New York State, but also with other important Early Cambrian continents, in particular with Australia, Antarctica, and Siberia. A middle Dyeran age is most probable for both the Bastion and Ella Island Formation, and the rich fossil assemblage facilitates correlation with the Botoman Stage of Siberia and its equivalents. One new taxon is described, the disc-shaped problematicum Tunudiscus duovittarius n. gen. and sp.

@article{doi101666002233602006801087ssfftu20co2,
    author = "Skovsted, Christian B.",
    title = "SMALL SHELLY FAUNA FROM THE UPPER LOWER CAMBRIAN BASTION AND ELLA ISLAND FORMATIONS, NORTH-EAST GREENLAND",
    year = "2006",
    journal = "Journal of Paleontology",
    abstract = "A diverse and well-preserved fauna of shelly fossils from the upper Lower Cambrian Bastion and Ella Island Formations of North-East Greenland contains more than 90 species. The fauna is the most diverse shelly fauna yet discovered in the Lower Cambrian of Laurentia and includes many fossils previously known only from other continental blocks. It enhances correlation of the North-East Greenland succession into Laurentia, most notably with the Browns Pond Formation of New York State, but also with other important Early Cambrian continents, in particular with Australia, Antarctica, and Siberia. A middle Dyeran age is most probable for both the Bastion and Ella Island Formation, and the rich fossil assemblage facilitates correlation with the Botoman Stage of Siberia and its equivalents. One new taxon is described, the disc-shaped problematicum Tunudiscus duovittarius n. gen. and sp.",
    url = "https://doi.org/10.1666/0022-3360(2006)80[1087:ssfftu]2.0.co;2",
    doi = "10.1666/0022-3360(2006)80[1087:ssfftu]2.0.co;2",
    openalex = "W2240717407",
    references = "doi101111j150239311993tb01502x, doi105479si009638011395227, ulrich1931cambrian"
}

Kerogens from the Lower and Middle Cambrian deposits of the Kuonamka Formation in the northeastern Siberian Platform have been analyzed by modern methods. We have determined the pyrolytic characteristics of insoluble organic matter and the contents of C, H, S, N, O, and the stable C isotope. The type and catagenesis of organic matter have been estimated, as well as the generating potential of oil source rocks. It has been found that the composition of kerogens taken from the Molodo River outcrops was affected by supergene processes and that the degree of their alteration is related to the organic content of rocks and their structure.

@article{parfenova2010kerogen,
    author = "Parfenova, T.M. and Kontorovich, A.E. and Borisova, L.S. and Melenevskii, V.N.",
    title = "Kerogen from the Cambrian deposits of the Kuonamka Formation (northeastern Siberian Platform)",
    year = "2010",
    journal = "Russian Geology and Geophysics",
    abstract = "Kerogens from the Lower and Middle Cambrian deposits of the Kuonamka Formation in the northeastern Siberian Platform have been analyzed by modern methods. We have determined the pyrolytic characteristics of insoluble organic matter and the contents of C, H, S, N, O, and the stable C isotope. The type and catagenesis of organic matter have been estimated, as well as the generating potential of oil source rocks. It has been found that the composition of kerogens taken from the Molodo River outcrops was affected by supergene processes and that the degree of their alteration is related to the organic content of rocks and their structure.",
    url = "https://doi.org/10.1016/j.rgg.2010.02.004",
    doi = "10.1016/j.rgg.2010.02.004",
    number = "3",
    pages = "277-285",
    volume = "51"
}

@article{doi101016jjafrearsci201106003,
    author = "Etemad‐Saeed, Najmeh and Hosseini-Barzi, Mahboobeh and Armstrong‐Altrin, John S.",
    title = "Petrography and geochemistry of clastic sedimentary rocks as evidences for provenance of the Lower Cambrian Lalun Formation, Posht-e-badam block, Central Iran",
    year = "2011",
    journal = "Journal of African Earth Sciences",
    url = "https://doi.org/10.1016/j.jafrearsci.2011.06.003",
    doi = "10.1016/j.jafrearsci.2011.06.003",
    openalex = "W2036578862",
    references = "doi103133ofr81743"
}

Abstract The bitumen of the Lower Cretaceous McMurray Formation in Alberta arguably represents one of the most important hydrocarbon accumulations in the world. In-situ development relies on heat transfer through the reservoir via horizontal steam injection wells placed 4 to 6 m (13–20 ft) above horizontal producers near the base of the sandstone reservoirs. Given this technology, understanding the distribution of the resource is paramount for a successful development program. Sedimentary facies provide a direct control on bitumen distribution and recovery. Most facies models developed to describe and predict sedimentary units of the McMurray Formation consider fluvial, estuarine, and/or deltaic depositional settings. In-situ development, however, requires a particularly high-resolution sedimentologic interpretation. High-quality three-dimensional seismic reflection data and extensive drill cores from acreage located approximately 50 km (31 mi) south of Fort McMurray provide important insights into the sedimentologic organization of reservoir and nonreservoir deposits in the upper one third (40 m [131 ft]) of the reservoir interval. Geomorphologic characteristics of the strata observed in seismic time slices reveal that a fluvial depositional setting was prevalent. Ichnologic and palynologic data, as well as sedimentary structures suggestive of tidal processes, indicate a marine influence in the upper reaches of a fluvial system characterized by channels that were 390 to 640 m (1280–2100 ft) wide and 28 to 36 m (92–118 ft) deep. The complex stratigraphic architecture consists of a mosaic of large-scale depositional elements, including abandoned channels or oxbow lake fills, point bars associated with lateral accretion, point bars associated with downstream accretion, counter point bars, and sandstone-filled channels. Reservoir deposits are primarily associated with point bars and sandstone-filled channels.

@article{doi10130612131010111,
    author = "Hubbard, Stephen M. and Smith, Derald G. and Nielsen, Haley and Leckie, Dale A. and Fustic, Milovan and Spencer, Ronald J. and Bloom, Lorraine",
    title = "Seismic geomorphology and sedimentology of a tidally influenced river deposit, Lower Cretaceous Athabasca oil sands, Alberta, Canada",
    year = "2011",
    journal = "AAPG Bulletin",
    abstract = "Abstract The bitumen of the Lower Cretaceous McMurray Formation in Alberta arguably represents one of the most important hydrocarbon accumulations in the world. In-situ development relies on heat transfer through the reservoir via horizontal steam injection wells placed 4 to 6 m (13–20 ft) above horizontal producers near the base of the sandstone reservoirs. Given this technology, understanding the distribution of the resource is paramount for a successful development program. Sedimentary facies provide a direct control on bitumen distribution and recovery. Most facies models developed to describe and predict sedimentary units of the McMurray Formation consider fluvial, estuarine, and/or deltaic depositional settings. In-situ development, however, requires a particularly high-resolution sedimentologic interpretation. High-quality three-dimensional seismic reflection data and extensive drill cores from acreage located approximately 50 km (31 mi) south of Fort McMurray provide important insights into the sedimentologic organization of reservoir and nonreservoir deposits in the upper one third (40 m [131 ft]) of the reservoir interval. Geomorphologic characteristics of the strata observed in seismic time slices reveal that a fluvial depositional setting was prevalent. Ichnologic and palynologic data, as well as sedimentary structures suggestive of tidal processes, indicate a marine influence in the upper reaches of a fluvial system characterized by channels that were 390 to 640 m (1280–2100 ft) wide and 28 to 36 m (92–118 ft) deep. The complex stratigraphic architecture consists of a mosaic of large-scale depositional elements, including abandoned channels or oxbow lake fills, point bars associated with lateral accretion, point bars associated with downstream accretion, counter point bars, and sandstone-filled channels. Reservoir deposits are primarily associated with point bars and sandstone-filled channels.",
    url = "https://doi.org/10.1306/12131010111",
    doi = "10.1306/12131010111",
    openalex = "W2160469173",
    references = "doi1010079783662010204, doi1010160037073880900524, doi101016jmarpetgeo200308003, doi101016s0037073887800064, doi101306212f7e4b2b2411d78648000102c1865d"
}

The name Lawsonian Stage is proposed as the highest stage of the Cambrian System (Stage 10). The base of the proposed Lawsonian Stage is at the First Appearance Datum (FAD) of the euconodont Eoconodontus notchpeakensis That horizon, the base of the E. notchpeakensis Subzone of the Eoconodontus Zone, is 3 m above the base of the Red Tops Member of the Notch Peak Formation at the Steamboat Pass section in the House Range, western Utah, USA. The conodont fauna of the Eoconodontus Zone is widespread in North America and occurs in Asia, Australia, Europe, and South America in facies that include cratonic nearshore sandstones, shallow and intermediate-depth platform carbonates, deep-water ramp, continental slope deposits, and deep-ocean radiolarian chert. This horizon lies at or slightly below the top of the Illaenurus trilobite Zone of western North America and within the lower part of the Saukiella junia Subzone of the Saukia Zone in areas east of the Rocky Mountains. These trilobite and conodont faunas can be traced into slope deposits containing cosmopolitan trilobites. The horizon is nearly coincident with the boundary between the Billingsella and the Finkelnburgia calcitic brachiopod Zones; ranges of organophosphatic brachiopods also characterize the horizon. A high-amplitude, negative, carbon-isotope excursion, the HERB Event, occurs in the Eoconodontus notchpeakensis Subzone. This distinctive geochemical signal is known in western Utah, Australia, China, and in poorly fossiliferous slope deposits in Newfoundland, Canada. The proposed boundary fits between two closely spaced sequence-stratigraphic boundaries described from Utah and Texas, USA.

@article{doi103140bullgeosci1255,
    author = "Miller, James F. and Evans, Kevin R. and Freeman, Rebecca and Ripperdan, Robert L. and Taylor, John F.",
    title = "Proposed stratotype for the base of the Lawsonian Stage (Cambrian Stage 10) at the First Appearance Datum of Eoconodontus notchpeakensis (Miller) in the House Range, Utah, USA",
    year = "2011",
    journal = "Bulletin of Geosciences",
    abstract = "The name Lawsonian Stage is proposed as the highest stage of the Cambrian System (Stage 10). The base of the proposed Lawsonian Stage is at the First Appearance Datum (FAD) of the euconodont Eoconodontus notchpeakensis That horizon, the base of the E. notchpeakensis Subzone of the Eoconodontus Zone, is 3 m above the base of the Red Tops Member of the Notch Peak Formation at the Steamboat Pass section in the House Range, western Utah, USA. The conodont fauna of the Eoconodontus Zone is widespread in North America and occurs in Asia, Australia, Europe, and South America in facies that include cratonic nearshore sandstones, shallow and intermediate-depth platform carbonates, deep-water ramp, continental slope deposits, and deep-ocean radiolarian chert. This horizon lies at or slightly below the top of the Illaenurus trilobite Zone of western North America and within the lower part of the Saukiella junia Subzone of the Saukia Zone in areas east of the Rocky Mountains. These trilobite and conodont faunas can be traced into slope deposits containing cosmopolitan trilobites. The horizon is nearly coincident with the boundary between the Billingsella and the Finkelnburgia calcitic brachiopod Zones; ranges of organophosphatic brachiopods also characterize the horizon. A high-amplitude, negative, carbon-isotope excursion, the HERB Event, occurs in the Eoconodontus notchpeakensis Subzone. This distinctive geochemical signal is known in western Utah, Australia, China, and in poorly fossiliferous slope deposits in Newfoundland, Canada. The proposed boundary fits between two closely spaced sequence-stratigraphic boundaries described from Utah and Texas, USA.",
    url = "https://doi.org/10.3140/bull.geosci.1255",
    doi = "10.3140/bull.geosci.1255",
    openalex = "W2317882425",
    references = "aldridge1992upper, doi101016003101829390075t, doi1011300091761319920201039scicis23co2, doi101130b252291, doi101130b261171, doi101130spe196p43, doi1018814epiiugs2001v24i1005, doi104095125053, doi105479si009638011395227, openalexw1553396379, openalexw2598637701"
}

@inproceedings{mitasov2012the,
    author = "Mitasov, V.I. and Kushmar, I.A. and Kondratev, V.A.",
    title = "The Prediction of Oil-gas Perspective Reservoirs in Terrigenous Vendian and Lower Cambrian Deposits of East Siberian",
    year = "2012",
    booktitle = "Proceedings",
    url = "https://doi.org/10.3997/2214-4609.20143660",
    doi = "10.3997/2214-4609.20143660"
}

@incollection{crossref2016caves,
    title = "Caves",
    year = "2016",
    booktitle = "Landscape, Nature, and the Sacred in Byzantium",
    url = "https://doi.org/10.1017/cbo9781316488386.008",
    doi = "10.1017/cbo9781316488386.008",
    pages = "176-202"
}

Abstract The Middle and Late Cambrian mixed carbonate–siliciclastic Abrigo Formation of southeastern Arizona was deposited during the Sauk transgression in the craton interior landward of the passive margin of Laurentia. It overlies shallow-marine sandstone of the Bolsa Quartzite, which mantled the Precambrian land surface. The Abrigo Formation consists of ten distinct rock types that comprise fifteen lithofacies, which are grouped into eight facies associations. The strata represent an array of shallow-marine environments that were dominated by wave and storm activity. The interpreted paleoenvironments include lower offshore, upper offshore, offshore transition, and lower, middle, and upper shoreface. These environments migrated laterally as a function of relative sea-level changes along with input of siliciclastic sediment and its effect on carbonate deposition. Stratigraphic distribution of facies indicates that there were two separate carbonate factories: one in the nearshore immediately seaward of the siliciclastic shoreface and the other in the distal offshore area. Correlation across 170 km of the study area suggests that these lithofacies were deposited in six temporally distinct phases involving two transgressive–highstand systems tract couplets during the Bolaspidela through Crepicephalus biozones, a falling-stage systems tract in the Aphelaspis Biozone, and a lowstand systems tract in the Elvinia Biozone following the Sauk II–Sauk III hiatus. In general, the mixed carbonate–siliciclastic depositional environment of the Abrigo Formation shows that fine-grained siliciclastic facies dominate the transgressive systems tract. By contrast, carbonate sedimentation was dominant mostly during the middle to late phase of the highstand. The upper part of the highstand systems tract records progradation of the sandy shoreface. Nevertheless, the ratio between siliciclastic and carbonate sediment in various bathymetric zones differs from previously described inner-detrital-belt examples of Cambrian age. In the Abrigo Formation, some bioclastic grainstone in shoreface deposits contains siliciclastic sand, indicating that the two were deposited together until sand was dominant. However, carbonate production and siliciclastic mud sedimentation were for the most part mutually exclusive, suggesting that the shallow-water carbonate factory during the Middle and Late Cambrian was vulnerable to poisoning from clay or nutrient input. Consequently, carbonate sedimentation in the offshore transition, located between sand-dominated shoreface and mixed carbonate–siliciclastic offshore facies, reflects the bypassing of siliciclastic mud.

@article{doi102110jsr201596,
    author = "Łabaj, Marcelina and Pratt, Brian R.",
    title = "Depositional Dynamics In A Mixed Carbonate–Siliciclastic System: Middle–Upper Cambrian Abrigo Formation, Southeastern Arizona, U.S.A.",
    year = "2016",
    journal = "Journal of Sedimentary Research",
    abstract = "Abstract The Middle and Late Cambrian mixed carbonate–siliciclastic Abrigo Formation of southeastern Arizona was deposited during the Sauk transgression in the craton interior landward of the passive margin of Laurentia. It overlies shallow-marine sandstone of the Bolsa Quartzite, which mantled the Precambrian land surface. The Abrigo Formation consists of ten distinct rock types that comprise fifteen lithofacies, which are grouped into eight facies associations. The strata represent an array of shallow-marine environments that were dominated by wave and storm activity. The interpreted paleoenvironments include lower offshore, upper offshore, offshore transition, and lower, middle, and upper shoreface. These environments migrated laterally as a function of relative sea-level changes along with input of siliciclastic sediment and its effect on carbonate deposition. Stratigraphic distribution of facies indicates that there were two separate carbonate factories: one in the nearshore immediately seaward of the siliciclastic shoreface and the other in the distal offshore area. Correlation across 170 km of the study area suggests that these lithofacies were deposited in six temporally distinct phases involving two transgressive–highstand systems tract couplets during the Bolaspidela through Crepicephalus biozones, a falling-stage systems tract in the Aphelaspis Biozone, and a lowstand systems tract in the Elvinia Biozone following the Sauk II–Sauk III hiatus. In general, the mixed carbonate–siliciclastic depositional environment of the Abrigo Formation shows that fine-grained siliciclastic facies dominate the transgressive systems tract. By contrast, carbonate sedimentation was dominant mostly during the middle to late phase of the highstand. The upper part of the highstand systems tract records progradation of the sandy shoreface. Nevertheless, the ratio between siliciclastic and carbonate sediment in various bathymetric zones differs from previously described inner-detrital-belt examples of Cambrian age. In the Abrigo Formation, some bioclastic grainstone in shoreface deposits contains siliciclastic sand, indicating that the two were deposited together until sand was dominant. However, carbonate production and siliciclastic mud sedimentation were for the most part mutually exclusive, suggesting that the shallow-water carbonate factory during the Middle and Late Cambrian was vulnerable to poisoning from clay or nutrient input. Consequently, carbonate sedimentation in the offshore transition, located between sand-dominated shoreface and mixed carbonate–siliciclastic offshore facies, reflects the bypassing of siliciclastic mud.",
    url = "https://doi.org/10.2110/jsr.2015.96",
    doi = "10.2110/jsr.2015.96",
    openalex = "W2295821911",
    references = "doi101016jsedgeo201309007, doi101016jsedgeo201309008, doi101016s089598110300097x"
}

There are rich oil and gas resources in marine carbonate strata worldwide. Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic, Cenozoic, and upper Paleozoic strata, oil and gas exploration in the Proterozoic–Lower Paleozoic (PLP) strata—the oldest marine strata—has been very limited. To more clearly understand the oil and gas formation conditions and distributions in the PLP marine carbonate strata, we analyzed and characterized the petroleum geological conditions, oil and gas reservoir types, and their distributions in thirteen giant oil and gas fields worldwide. This study reveals the main factors controlling their formation and distribution. Our analyses show that the source rocks for these giant oil and gas fields are mainly shale with a great abundance of type I–II organic matter and a high thermal evolution extent. The reservoirs are mainly gas reservoirs, and the reservoir rocks are dominated by dolomite. The reservoir types are mainly karst and reef–shoal bodies with well-developed dissolved pores and cavities, intercrystalline pores, and fractures. These reservoirs are highly heterogeneous. The burial depth of the reservoirs is highly variable and somewhat negatively correlated to the porosity. The cap rocks are mainly thick evaporites and shales, with the thickness of the cap rocks positively correlated to the oil and gas reserves. The development of high-quality evaporite cap rock is highly favorable for oil and gas preservation. We identified four hydrocarbon generation models, and that the major source rocks have undergone a long period of burial and thermal evolution and are characterized by early and long periods of hydrocarbon generation. These giant oil and gas fields have diverse types of reservoirs and are mainly distributed in paleo-uplifts, slope zones, and platform margin reef-shoal bodies. The main factors that control their formation and distribution were identified, enabling the prediction of new favorable areas for oil and gas exploration.

@article{doi101007s1218201701545,
    author = "Liu, Xiaoping and Jin, Zhijun and Bai, Guoping and Guan, Ming and Liu, Jie and Pan, Qinghua and Li, Ting and Xing, Yujie",
    title = "Formation and distribution characteristics of Proterozoic–Lower Paleozoic marine giant oil and gas fields worldwide",
    year = "2017",
    journal = "Petroleum Science",
    abstract = "There are rich oil and gas resources in marine carbonate strata worldwide. Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic, Cenozoic, and upper Paleozoic strata, oil and gas exploration in the Proterozoic–Lower Paleozoic (PLP) strata—the oldest marine strata—has been very limited. To more clearly understand the oil and gas formation conditions and distributions in the PLP marine carbonate strata, we analyzed and characterized the petroleum geological conditions, oil and gas reservoir types, and their distributions in thirteen giant oil and gas fields worldwide. This study reveals the main factors controlling their formation and distribution. Our analyses show that the source rocks for these giant oil and gas fields are mainly shale with a great abundance of type I–II organic matter and a high thermal evolution extent. The reservoirs are mainly gas reservoirs, and the reservoir rocks are dominated by dolomite. The reservoir types are mainly karst and reef–shoal bodies with well-developed dissolved pores and cavities, intercrystalline pores, and fractures. These reservoirs are highly heterogeneous. The burial depth of the reservoirs is highly variable and somewhat negatively correlated to the porosity. The cap rocks are mainly thick evaporites and shales, with the thickness of the cap rocks positively correlated to the oil and gas reserves. The development of high-quality evaporite cap rock is highly favorable for oil and gas preservation. We identified four hydrocarbon generation models, and that the major source rocks have undergone a long period of burial and thermal evolution and are characterized by early and long periods of hydrocarbon generation. These giant oil and gas fields have diverse types of reservoirs and are mainly distributed in paleo-uplifts, slope zones, and platform margin reef-shoal bodies. The main factors that control their formation and distribution were identified, enabling the prediction of new favorable areas for oil and gas exploration.",
    url = "https://doi.org/10.1007/s12182-017-0154-5",
    doi = "10.1007/s12182-017-0154-5",
    openalex = "W2606634908"
}

Abstract The δ 13 C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (~90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (upper) members. It is formed of slope marine carbonates alternating with shales (rhythmites) and conglomeratic interbeds. The preservation of the investigated micritic carbonates was meticulously evaluated by multiple petrographic and geochemical screening tools. The δ 13 C and δ 18 O values (−0.5 ± 0.8 ‰VPDB and −7.1 ± 0.3 ‰VPDB, respectively) exhibit insignificant correlation (R 2 = 0.002) and similarly the correlation of δ 13 C values with their Sr and Mn counterparts, which supports the preservation of at least near-primary δ 13 C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ 13 C profile exhibits two main negative excursions, a lower broad excursion (~3 ‰) that reaches its maximum at ~70 m below the Martin Point / Broom Point members boundary and an upper narrow excursion (~2.5 ‰) immediately below the same boundary. The lower excursion can be correlated with the global latest Furongian HERB event (TOCE), which is also recognized in the C-isotope profile of the GSSP boundary section at Green Point whereas the upper excursion matches with that of the Cambrian‒Ordovician boundary in the same section. The peak of the HERB δ 13 C excursion is correlated with positive shifts on the Th/U and Ni profiles (redox and productivity proxies).

@article{doi101017s001675681800002x,
    author = "Azmy, Karem",
    title = "Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation",
    year = "2018",
    journal = "Geological Magazine",
    abstract = "Abstract The δ 13 C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (\textasciitilde 90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (upper) members. It is formed of slope marine carbonates alternating with shales (rhythmites) and conglomeratic interbeds. The preservation of the investigated micritic carbonates was meticulously evaluated by multiple petrographic and geochemical screening tools. The δ 13 C and δ 18 O values (−0.5 ± 0.8 ‰VPDB and −7.1 ± 0.3 ‰VPDB, respectively) exhibit insignificant correlation (R 2 = 0.002) and similarly the correlation of δ 13 C values with their Sr and Mn counterparts, which supports the preservation of at least near-primary δ 13 C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ 13 C profile exhibits two main negative excursions, a lower broad excursion (\textasciitilde 3 ‰) that reaches its maximum at \textasciitilde 70 m below the Martin Point / Broom Point members boundary and an upper narrow excursion (\textasciitilde 2.5 ‰) immediately below the same boundary. The lower excursion can be correlated with the global latest Furongian HERB event (TOCE), which is also recognized in the C-isotope profile of the GSSP boundary section at Green Point whereas the upper excursion matches with that of the Cambrian‒Ordovician boundary in the same section. The peak of the HERB δ 13 C excursion is correlated with positive shifts on the Th/U and Ni profiles (redox and productivity proxies).",
    url = "https://doi.org/10.1017/s001675681800002x",
    doi = "10.1017/s001675681800002x",
    openalex = "W2791026833",
    references = "doi1010160016703790901288, doi101016001670379290064p, doi101016s0009254199000819, doi101017s0016756817000188, doi101126science27252651155, doi1011300016760620011130443oicftl20co2, doi101130b256301, doi10130674d714f62b2111d78648000102c1865d, doi1018814epiiugs2001v24i1005, doi102110scn91250037, doi10247501200702, doi103140bullgeosci1255"
}

The article describes Cambrian reservoirs in the territory of the Turukhano-Irkutsk-Olekminsky facies region, which covers the territory of the southern and central parts of Eastern Siberia and Western Yakutia. In recent years, a significant amount of geological and geophysical work has been carried out on this territory, which made it possible to significantly clarify the oil and gas content of the subsalt and inter-salt Cambrian sediments. It has been shown that Cambrian carbonate horizons are characterized by incompetence of reservoir properties, which is associated with different facial conditions of sediment accumulation, as well as with the development of secondary processes.

@article{fomin2019characteristics,
    author = "Fomin, Andrey and Moiseev, Sergey",
    title = "CHARACTERISTICS OF OIL AND GAS TANKS IN CAMBRIAN DEPOSITS OF THE CENTRAL PART OF THE SIBERIAN PLATFORM",
    year = "2019",
    journal = "Interexpo GEO-Siberia",
    abstract = "The article describes Cambrian reservoirs in the territory of the Turukhano-Irkutsk-Olekminsky facies region, which covers the territory of the southern and central parts of Eastern Siberia and Western Yakutia. In recent years, a significant amount of geological and geophysical work has been carried out on this territory, which made it possible to significantly clarify the oil and gas content of the subsalt and inter-salt Cambrian sediments. It has been shown that Cambrian carbonate horizons are characterized by incompetence of reservoir properties, which is associated with different facial conditions of sediment accumulation, as well as with the development of secondary processes.",
    url = "https://doi.org/10.33764/2618-981x-2019-2-1-183-191",
    doi = "10.33764/2618-981x-2019-2-1-183-191",
    number = "1",
    pages = "183-191",
    volume = "2"
}

The results of paleohydrogeochemical reconstructions of the Lower Cambrian deposits of the Siberian platform are presented. The characteristic of the main biota groups of the Early Cambrian time of the Siberian paleobasin is given. The conditions of formation and compositional features of syngenetic waters are considered. The modern chemistry of the inter–salt brines is mainly of an inherited nature, while the appearance of super–strong brines of calcium chloride composition is due to the processes of deep interaction of the initial sea brine with the host rocks. Based on the analysis of the hydrogeochemical features of the Lower Cambrian sediments, the prediction of the zones of distribution of potassium salts is given.

@inproceedings{andchernykh2020features,
    author = "Chernykh, Anatoly V. and Tokarev, Dmitry A. and Novikov, Dmitry A. and Dultsev, Fedor F.",
    title = "Features of paleohydrogeochemistry of the lower cambrian deposits of the Siberian Platform",
    year = "2020",
    booktitle = "Недропользование. Горное дело. Направления и технологии поиска, разведки и разработки месторождений полезных ископаемых. Экономика. Геоэкология: Материалы XVI международной конференции (20-24 апреля 2020, Новосибирск)",
    abstract = "The results of paleohydrogeochemical reconstructions of the Lower Cambrian deposits of the Siberian platform are presented. The characteristic of the main biota groups of the Early Cambrian time of the Siberian paleobasin is given. The conditions of formation and compositional features of syngenetic waters are considered. The modern chemistry of the inter–salt brines is mainly of an inherited nature, while the appearance of super–strong brines of calcium chloride composition is due to the processes of deep interaction of the initial sea brine with the host rocks. Based on the analysis of the hydrogeochemical features of the Lower Cambrian sediments, the prediction of the zones of distribution of potassium salts is given.",
    url = "https://doi.org/10.18303/b978-5-4262-0102-6-2020-026",
    doi = "10.18303/b978-5-4262-0102-6-2020-026",
    pages = "256-268"
}

Plenty of pyrobitumens were found throughout the Sinian Dengying and Cambrian Longwangmiao reservoirs of the Anyue gas field in the central Sichuan Basin. However, their genetic sources and formation processes still remain less constrained due to their strong heterogeneity in carbon isotopes and contents. In this study, an oil sample collected from the Devonian bituminous sandstones in the northwestern Sichuan Basin, along with its four fractions (i.e., saturates, aromatics, resins, asphaltenes (SARA)), was pyrolyzed in sealed gold tubes to investigate the generation and evolution process of pyrobitumen. Experimental results show that the four fractions generate pyrobitumen at different thermal maturity stages during oil cracking and the pyrobitumen yields of different oil fractions follow the following order: asphaltenes > resins > aromatics > saturates. For the pyrobitumen generated from the same oil fraction, the stable carbon isotopes of pyrobitumen become only slightly heavier with increasing maturation. At the same level of thermal maturity, pyrobitumen from saturates is more enriched in 13C than those from the other three oil fractions, and the maximum difference is over 2‰. Based on the experimental results, kinetic parameters for pyrobitumen generation from the four oil fractions were determined and then applied to investigate the origin and formation time of pyrobitumen in the Sinian Dengying and the Cambrian Longwangmiao reservoirs. The results show that the pyrobitumen in both the Sinian and the Cambrian reservoirs were mainly formed during the middle Jurassic to early Cretaceous. Although the pyrobitumen yields are significantly dependent on the SARA composition of oils, the change in pyrobitumen carbon isotopes is usually less than 1‰. This indicates that the carbon isotopes of pyrobitumen are mainly controlled by the initial carbon isotopes of SARA fractions that are closely related to their source rocks. Based on the carbon isotopes of pyrobitumen and potential source rocks, the precursor oils of pyrobitumen in the Cambrian Longwangmiao reservoirs are mainly derived from the Lower Cambrian Qiongzhusi source rock, while the precursor oils of pyrobitumen in the Sinian Dengying reservoirs are mixed oils sourced from both the Sinian and the Lower Cambrian source rocks.

@article{doi101021acsenergyfuels0c03263,
    author = "Wang, Xing and Tian, Hui and Zhou, Qin and He, Chunmin",
    title = "Origin and Formation of Pyrobitumen in Sinian–Cambrian Reservoirs of the Anyue Gas Field in the Sichuan Basin: Implications from Pyrolysis Experiments of Different Oil Fractions",
    year = "2020",
    journal = "Energy \& Fuels",
    abstract = "Plenty of pyrobitumens were found throughout the Sinian Dengying and Cambrian Longwangmiao reservoirs of the Anyue gas field in the central Sichuan Basin. However, their genetic sources and formation processes still remain less constrained due to their strong heterogeneity in carbon isotopes and contents. In this study, an oil sample collected from the Devonian bituminous sandstones in the northwestern Sichuan Basin, along with its four fractions (i.e., saturates, aromatics, resins, asphaltenes (SARA)), was pyrolyzed in sealed gold tubes to investigate the generation and evolution process of pyrobitumen. Experimental results show that the four fractions generate pyrobitumen at different thermal maturity stages during oil cracking and the pyrobitumen yields of different oil fractions follow the following order: asphaltenes > resins > aromatics > saturates. For the pyrobitumen generated from the same oil fraction, the stable carbon isotopes of pyrobitumen become only slightly heavier with increasing maturation. At the same level of thermal maturity, pyrobitumen from saturates is more enriched in 13C than those from the other three oil fractions, and the maximum difference is over 2‰. Based on the experimental results, kinetic parameters for pyrobitumen generation from the four oil fractions were determined and then applied to investigate the origin and formation time of pyrobitumen in the Sinian Dengying and the Cambrian Longwangmiao reservoirs. The results show that the pyrobitumen in both the Sinian and the Cambrian reservoirs were mainly formed during the middle Jurassic to early Cretaceous. Although the pyrobitumen yields are significantly dependent on the SARA composition of oils, the change in pyrobitumen carbon isotopes is usually less than 1‰. This indicates that the carbon isotopes of pyrobitumen are mainly controlled by the initial carbon isotopes of SARA fractions that are closely related to their source rocks. Based on the carbon isotopes of pyrobitumen and potential source rocks, the precursor oils of pyrobitumen in the Cambrian Longwangmiao reservoirs are mainly derived from the Lower Cambrian Qiongzhusi source rock, while the precursor oils of pyrobitumen in the Sinian Dengying reservoirs are mixed oils sourced from both the Sinian and the Lower Cambrian source rocks.",
    url = "https://doi.org/10.1021/acs.energyfuels.0c03263",
    doi = "10.1021/acs.energyfuels.0c03263",
    openalex = "W3117979763",
    references = "doi101111jpg12561"
}

@article{akhmedova2021features,
    author = "AKHMEDOVA, A. R. and SEREBRENNIKOVA, O. V. and SHIGANOVA, O. V.",
    title = "Features of the composition and properties of oils from vendian-lower cambrian and riphean deposits in the central part of the siberian platform",
    year = "2021",
    journal = "Chemistry for Sustainable Development",
    url = "https://doi.org/10.15372/csd2021316",
    doi = "10.15372/csd2021316",
    number = "4",
    pages = "381-390",
    volume = "29"
}

Continuous and biostratigraphically well-constrained carbon isotope (δ13Corg) profiles through the upper Miaolingian (middle Cambrian) to Tremadocian (Lower Ordovician) part of the Alum Shale Formation in four drill cores from southernmost Scandinavia are described. The sections record seven Furongian (upper Cambrian) excursions/spikes, of which three appear valuable as auxiliary markers for identifying global stage boundaries. The Steptoean Positive Carbon Isotope Excursion (SPICE) event with a magnitude of up to 2.8‰ is located mainly within the Olenus Superzone. The onset, as specified here, coincides with the end-Marjuman extinction and is marked by a minor negative excursion (up to −1.6‰) right below the Miaolingian–Furongian boundary. The end of the SPICE event approximates the upper boundary of the Olenus Superzone and has potential for correlation of the Paibian–Jiangshanian boundary. The Top of Cambrian Excursion (TOCE) with a magnitude of about −1.6‰ straddles the Parabolina lobata–Parabolina heres megalops zonal boundary in Baltoscandia. This chemostratigraphic excursion, considered as a synonym of the Hellnmaria-Red Tops Boundary excursion (HERB), represents a secondary marker for correlating the base of Stage 10, if defined by the FAD of Eoconodontus notchpeakensis. A positive spike at the Cambrian–Ordovician boundary, here named COBS, recognized in the stratotype section at Green Point (Canada; δ13Ccarb magnitude +5.3‰), Scandinavia (δ13Corg magnitude up to +2.2‰) and elsewhere, appears as a valuable supplementary marker for recognizing this important boundary. The described δ13Corg profile from the Albjära-1 core provides a standard reference for Furongian carbon isotope chemostratigraphy in Baltica, refines the correlation between Baltica and other palaeocontinents, and indicates new possibilities for pinpointing international stage boundaries within the Furongian based on carbon isotope records.

@article{doi101016jgloplacha2022103751,
    author = "Zhao, Zhengfu and Ahlberg, Per and Thibault, Nicolas and Dahl, Tais W. and Schovsbo, Niels H. and Nielsen, Arne Thorshøj",
    title = "High-resolution carbon isotope chemostratigraphy of the middle Cambrian to lowermost Ordovician in southern Scandinavia: Implications for global correlation",
    year = "2022",
    journal = "Global and Planetary Change",
    abstract = "Continuous and biostratigraphically well-constrained carbon isotope (δ13Corg) profiles through the upper Miaolingian (middle Cambrian) to Tremadocian (Lower Ordovician) part of the Alum Shale Formation in four drill cores from southernmost Scandinavia are described. The sections record seven Furongian (upper Cambrian) excursions/spikes, of which three appear valuable as auxiliary markers for identifying global stage boundaries. The Steptoean Positive Carbon Isotope Excursion (SPICE) event with a magnitude of up to 2.8‰ is located mainly within the Olenus Superzone. The onset, as specified here, coincides with the end-Marjuman extinction and is marked by a minor negative excursion (up to −1.6‰) right below the Miaolingian–Furongian boundary. The end of the SPICE event approximates the upper boundary of the Olenus Superzone and has potential for correlation of the Paibian–Jiangshanian boundary. The Top of Cambrian Excursion (TOCE) with a magnitude of about −1.6‰ straddles the Parabolina lobata–Parabolina heres megalops zonal boundary in Baltoscandia. This chemostratigraphic excursion, considered as a synonym of the Hellnmaria-Red Tops Boundary excursion (HERB), represents a secondary marker for correlating the base of Stage 10, if defined by the FAD of Eoconodontus notchpeakensis. A positive spike at the Cambrian–Ordovician boundary, here named COBS, recognized in the stratotype section at Green Point (Canada; δ13Ccarb magnitude +5.3‰), Scandinavia (δ13Corg magnitude up to +2.2‰) and elsewhere, appears as a valuable supplementary marker for recognizing this important boundary. The described δ13Corg profile from the Albjära-1 core provides a standard reference for Furongian carbon isotope chemostratigraphy in Baltica, refines the correlation between Baltica and other palaeocontinents, and indicates new possibilities for pinpointing international stage boundaries within the Furongian based on carbon isotope records.",
    url = "https://doi.org/10.1016/j.gloplacha.2022.103751",
    doi = "10.1016/j.gloplacha.2022.103751",
    openalex = "W4206963483",
    references = "doi101007s1143001792910, doi101007s125830170963x, doi1010160037073879900770, doi101016jpalwor200610016, doi101016s0031018200001280, doi101016s0031018203003651, doi1010179781316225523, doi101017s0016756817000188, doi101017s001675681800002x, doi101038nature09700, doi101073pnas1011836108, doi1018814epiiugs2001v24i1005, doi103140bullgeosci1255, müller1991upper, openalexw286951878"
}

The Avalonia microcontinent has diagnostic terminal Ediacaran–Ordovician lithostratigraphy, depositional sequence architecture, and igneous activity that extends for 2000+ km reflecting epeirogeny related to the Avalonian transform fault. Avalonia records an abrupt early Middle Cambrian (late Wuliuan) change from green, purple, or light grey to overlying black, dark grey, and brown facies in platform and off-platform areas (Meguma, North Wales). This change within one trilobite zone marks onset of ca. 26 m.y. of shallow-marine anoxia/strong dysoxia lasting into the Ordovician with Hatch Hill oxygenated mid-water zone (OMZ) onlap onto the shelf. A Bakken model (new, based on the middle Paleozoic Bakken Formation) is applied to shallow-shelf–shoreline organic-rich mud deposition. Erosion of greenish Avalonian depositional sequence (Ads) 7 was followed by Ads 8 tilting, volcanism, debris flows, and bentonite deposition on a cryptic unconformity in SE Newfoundland. The early Middle Cambrian age of the Ads 7–8 boundary is obscured by referring the lower Manuels River Formation and Cristallinium cambriense Zone to the younger Drumian Stage. Ads 8 has thin ashes in coterminous British and North American Avalonia where erosion and subaerial exposure with caliche development preceded onlap of upper Middle or Upper Cambrian Ads 9 black muds and sands. The green–black change emphasizes Avalonian unity; it precludes multiple Avalonian “micro-terranes” or assigning parts of Avalonia to West Gondwana or “Ganderia” (the Little River, Brookville, and Bras d'Or “terranes” are part of the Avalonian marginal platform). Coeval green–black transitions and similar later Cambrian faunas show comparable paleoenvironments in Avalonia and Baltica.

@article{doi101139cjes20220065,
    author = "Landing, Ed and Westrop, Stephen R. and Geyer, Gerd",
    title = "Trans-Avalonian green–black boundary (early Middle Cambrian): transform fault-driven epeirogeny and onset of 26 m.y. of shallow-marine, black mudstone in Avalonia (Rhode Island–Belgium) and Baltica",
    year = "2022",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The Avalonia microcontinent has diagnostic terminal Ediacaran–Ordovician lithostratigraphy, depositional sequence architecture, and igneous activity that extends for 2000+ km reflecting epeirogeny related to the Avalonian transform fault. Avalonia records an abrupt early Middle Cambrian (late Wuliuan) change from green, purple, or light grey to overlying black, dark grey, and brown facies in platform and off-platform areas (Meguma, North Wales). This change within one trilobite zone marks onset of ca. 26 m.y. of shallow-marine anoxia/strong dysoxia lasting into the Ordovician with Hatch Hill oxygenated mid-water zone (OMZ) onlap onto the shelf. A Bakken model (new, based on the middle Paleozoic Bakken Formation) is applied to shallow-shelf–shoreline organic-rich mud deposition. Erosion of greenish Avalonian depositional sequence (Ads) 7 was followed by Ads 8 tilting, volcanism, debris flows, and bentonite deposition on a cryptic unconformity in SE Newfoundland. The early Middle Cambrian age of the Ads 7–8 boundary is obscured by referring the lower Manuels River Formation and Cristallinium cambriense Zone to the younger Drumian Stage. Ads 8 has thin ashes in coterminous British and North American Avalonia where erosion and subaerial exposure with caliche development preceded onlap of upper Middle or Upper Cambrian Ads 9 black muds and sands. The green–black change emphasizes Avalonian unity; it precludes multiple Avalonian “micro-terranes” or assigning parts of Avalonia to West Gondwana or “Ganderia” (the Little River, Brookville, and Bras d'Or “terranes” are part of the Avalonian marginal platform). Coeval green–black transitions and similar later Cambrian faunas show comparable paleoenvironments in Avalonia and Baltica.",
    url = "https://doi.org/10.1139/cjes-2022-0065",
    doi = "10.1139/cjes-2022-0065",
    openalex = "W4293704644",
    references = "doi101038s41467022296514, doi1018814epiiugs2020020088"
}

This article presents a detailed biostratigraphic analysis of the Cambrian Series 2 Ribota and Huérmeda formations of four sections of the Iberian Chains (NE Spain), and a systematic study of their trilobite faunas. We identified four major assemblages: two in the middle part of the Ribota Formation, one at the base of the Huérmeda Formation and one at the top of the Huérmeda Formation. The studied species permit the assignment of these formations to the middle and upper Marianian and probably lower Bilbilian stages in the regional stratigraphic chart for the Iberian Peninsula, which correlates with an interval around the Cambrian Stage 3–4 boundary. The assemblages exhibit a great correlation potential with the presence of Termierella and the first figured material of Andalusiana from the Iberian Chains, two characteristic taxa of the Marianian of the Ossa-Morena Zone, having been also recorded from the Central Iberian Zone and Morocco. In addition, specimens tentatively assigned to Hebediscus are recorded for the first time from the region, a taxon with a wide geographic distribution which allows a good international correlation in the Cambrian Series 2.

@article{doi107203sjp24492,
    author = "Sepúlveda, Alexandre and Liñán, Eladio and Chirivella, Juan B. and Vintaned, José Antonio Gámez and Gozalo, Rodolfo",
    title = "Biostratigraphy of the Ribota and Huérmeda formations (Cambrian Series 2) in the Comarca del Aranda (Zaragoza province), Iberian Chains (NE Spain)",
    year = "2022",
    journal = "Spanish Journal of Palaeontology",
    abstract = "This article presents a detailed biostratigraphic analysis of the Cambrian Series 2 Ribota and Huérmeda formations of four sections of the Iberian Chains (NE Spain), and a systematic study of their trilobite faunas. We identified four major assemblages: two in the middle part of the Ribota Formation, one at the base of the Huérmeda Formation and one at the top of the Huérmeda Formation. The studied species permit the assignment of these formations to the middle and upper Marianian and probably lower Bilbilian stages in the regional stratigraphic chart for the Iberian Peninsula, which correlates with an interval around the Cambrian Stage 3–4 boundary. The assemblages exhibit a great correlation potential with the presence of Termierella and the first figured material of Andalusiana from the Iberian Chains, two characteristic taxa of the Marianian of the Ossa-Morena Zone, having been also recorded from the Central Iberian Zone and Morocco. In addition, specimens tentatively assigned to Hebediscus are recorded for the first time from the region, a taxon with a wide geographic distribution which allows a good international correlation in the Cambrian Series 2.",
    url = "https://doi.org/10.7203/sjp.24492",
    doi = "10.7203/sjp.24492",
    openalex = "W4281748219",
    references = "doi1018814epiiugs2020020088"
}

Abstract High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma (Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma (Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma (Kiskinella cristata Zone) and 506.25 ± 0.07 Ma (Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possible Oryctocephalus indicus -plexus, invariable dysoxic lithofacies control of O. indicus and diachronous occurrence of O. indicus in temporally distinct δ 13 C chemozones in South China and SW Laurentia. The lowest occurrence of O. indicus assemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6.

@article{doi101017s0016756823000729,
    author = "Landing, Ed and Schmitz, Mark D. and Westrop, Stephen R. and Geyer, Gerd",
    title = "U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit",
    year = "2023",
    journal = "Geological Magazine",
    abstract = "Abstract High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma (Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma (Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma (Kiskinella cristata Zone) and 506.25 ± 0.07 Ma (Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possible Oryctocephalus indicus -plexus, invariable dysoxic lithofacies control of O. indicus and diachronous occurrence of O. indicus in temporally distinct δ 13 C chemozones in South China and SW Laurentia. The lowest occurrence of O. indicus assemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6.",
    url = "https://doi.org/10.1017/s0016756823000729",
    doi = "10.1017/s0016756823000729",
    openalex = "W4389310601",
    references = "doi1018814epiiugs2020020088"
}

The geologically rapid appearance of fossils of modern animal phyla within Cambrian strata is a defining characteristic of the history of life on Earth. However, temporal calibration of the base of the Cambrian Period remains uncertain within millions of years, which has resulted in mounting challenges to the concept of a discrete Cambrian explosion. We present precise zircon U-Pb dates for the lower Wood Canyon Formation, Nevada. These data demonstrate the base of the Cambrian Period, as defined by both ichnofossil biostratigraphy and carbon isotope chemostratigraphy, was younger than 533 Mya, at least 6 My later than currently recognized. This new geochronology condenses previous age models for the Nemakit-Daldynian (early Cambrian) and, integrated with global records, demonstrates an explosive tempo to the early radiation of modern animal phyla.

@article{doi101073pnas2301478120,
    author = "Nelson, Lyle L. and Crowley, James L. and Smith, Emily F. and Schwartz, Darin and Hodgin, Eben B. and Schmitz, Mark D.",
    title = "Cambrian explosion condensed: High-precision geochronology of the lower Wood Canyon Formation, Nevada",
    year = "2023",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The geologically rapid appearance of fossils of modern animal phyla within Cambrian strata is a defining characteristic of the history of life on Earth. However, temporal calibration of the base of the Cambrian Period remains uncertain within millions of years, which has resulted in mounting challenges to the concept of a discrete Cambrian explosion. We present precise zircon U-Pb dates for the lower Wood Canyon Formation, Nevada. These data demonstrate the base of the Cambrian Period, as defined by both ichnofossil biostratigraphy and carbon isotope chemostratigraphy, was younger than 533 Mya, at least 6 My later than currently recognized. This new geochronology condenses previous age models for the Nemakit-Daldynian (early Cambrian) and, integrated with global records, demonstrates an explosive tempo to the early radiation of modern animal phyla.",
    url = "https://doi.org/10.1073/pnas.2301478120",
    doi = "10.1073/pnas.2301478120",
    openalex = "W4384499690",
    references = "doi101016b978012824360200019x, doi102110sedred200314, doi103133pp620"
}

The lower Cambrian Qiongzhusi (Є1q) shale in the Sichuan Basin, formerly considered a source rock, recently achieved high gas production (7.388 × 105 m3·d−1) from well Z201 in the Deyang–Anyue rift trough (DART), marking an exploration breakthrough of the world’s oldest industrial shale gas reservoir. However, the shale gas enrichment mechanism within the DART is not fully understood. This study reviews the formation of the Qiongzhusi shale gas reservoirs within the DART by comparing them with cotemporaneous deposits outside the DART, and several findings are presented. The gas production interval was correlated with the main phase of the Cambrian explosion (lower Cambrian stage 3). In the early Cambrian ecosystem, dominant animals likely accelerated the settling rates of organic matter (OM) in the upper 1st member of Є1q (Є1q12) by feeding on small planktonic organisms and producing larger organic fragments and fecal pellets. High primary productivity and euxinic conditions contributed to OM enrichment in the lower 1st member of Є1q (Є1q11). Additionally, shale reservoirs inside the DART demonstrated better properties than those outside in terms of thickness, brittle minerals, gas content, and porosity. In particular, the abundant OM pores inside the DART facilitated shale gas enrichment, whereas the higher thermal maturity of the shales outside the DART possibly led to the graphitization and collapse of some OM pores. Meanwhile, the overpressure of high-production wells inside the DART generally reflects better shale gas preservation, benefiting from the shale’s self-sealing nature, “upper capping and lower plugging” configuration, and limited faults and microfractures. Considering these insights, we introduced a “ternary enrichment” model for the Qiongzhusi shale gas. Although the current high gas production of Z201 was found at the reservoir 3, two additional reservoirs were identified with significant potential, thus suggesting a “multilayer stereoscopic development” strategy in future shale gas exploration within the DART.

@article{doi101016jeng202403007,
    author = "Zou, Caineng and Zhao, Zhengfu and Pan, Songqi and Yin, Jia and Lu, Guanwen and Fu, Fangliang and Yuan, Ming and Liu, Hanlin and Zhang, Guosheng and Luo, Cui and Wang, Wei and Jing, Zhenhua",
    title = "Unveiling the Oldest Industrial Shale Gas Reservoir: Insights for the Enrichment Pattern and Exploration Direction of Lower Cambrian Shale Gas in the Sichuan Basin",
    year = "2024",
    journal = "Engineering",
    abstract = "The lower Cambrian Qiongzhusi (Є1q) shale in the Sichuan Basin, formerly considered a source rock, recently achieved high gas production (7.388 × 105 m3·d−1) from well Z201 in the Deyang–Anyue rift trough (DART), marking an exploration breakthrough of the world’s oldest industrial shale gas reservoir. However, the shale gas enrichment mechanism within the DART is not fully understood. This study reviews the formation of the Qiongzhusi shale gas reservoirs within the DART by comparing them with cotemporaneous deposits outside the DART, and several findings are presented. The gas production interval was correlated with the main phase of the Cambrian explosion (lower Cambrian stage 3). In the early Cambrian ecosystem, dominant animals likely accelerated the settling rates of organic matter (OM) in the upper 1st member of Є1q (Є1q12) by feeding on small planktonic organisms and producing larger organic fragments and fecal pellets. High primary productivity and euxinic conditions contributed to OM enrichment in the lower 1st member of Є1q (Є1q11). Additionally, shale reservoirs inside the DART demonstrated better properties than those outside in terms of thickness, brittle minerals, gas content, and porosity. In particular, the abundant OM pores inside the DART facilitated shale gas enrichment, whereas the higher thermal maturity of the shales outside the DART possibly led to the graphitization and collapse of some OM pores. Meanwhile, the overpressure of high-production wells inside the DART generally reflects better shale gas preservation, benefiting from the shale’s self-sealing nature, “upper capping and lower plugging” configuration, and limited faults and microfractures. Considering these insights, we introduced a “ternary enrichment” model for the Qiongzhusi shale gas. Although the current high gas production of Z201 was found at the reservoir 3, two additional reservoirs were identified with significant potential, thus suggesting a “multilayer stereoscopic development” strategy in future shale gas exploration within the DART.",
    url = "https://doi.org/10.1016/j.eng.2024.03.007",
    doi = "10.1016/j.eng.2024.03.007",
    openalex = "W4393857299",
    references = "doi101016jgloplacha2022103751, doi101038s41467022296514"
}

Ancient epicratonic formations, which represent the bulk of pre-Jurassic sedimentary rocks, have been widely interpreted as marine deposits, but recently developed bulk-shale elemental proxies for palaeo-watermass salinity (i.e. B/Ga, Sr/Ba and S/TOC, where TOC is total organic carbon) have shown this inference to be frequently incorrect. Here, we use these proxies to test the salinity conditions of 22 representative shale and marl formations of early Cambrian to early Silurian age from five cratons (Laurentia, Avalonia, Baltica, Iran and South China) in the context of formation-specific palaeogeographical and palaeoclimatic reconstructions. Our dataset shows that around half of these formations were probably deposited under brackish or mixed brackish–marine conditions rather than fully marine conditions (as previously inferred), and that one of them represents a freshwater facies (previously interpreted as marine mainly on the basis of Cruziana traces). In most cases, the development of reduced-salinity conditions can be related to the coastal and/or humid climate belt setting in which the formation of interest was deposited. Our dataset also reveals systematically low Sr/Ba values (i.e. relative to modern brackish and marine facies), suggesting that seawater Sr concentrations were lower during the Early Paleozoic than at present. Our findings suggest that re-evaluation of the salinity characteristics of many ancient epicratonic shale and marl formations is necessary. Supplementary material: A supplementary figure and tables are available at https://doi.org/10.6084/m9.figshare.c.7063365 Thematic collection: This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at: https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system

@article{doi101144jgs2023217,
    author = "Liu, Zhanhong and Algeo, Thomas J. and Arefifard, Sakineh and Wei, Wei and Brett, Carlton E. and Landing, Ed and Lev, Steven",
    title = "Testing the salinity of Cambrian to Silurian epicratonic seas",
    year = "2024",
    journal = "Journal of the Geological Society",
    abstract = "Ancient epicratonic formations, which represent the bulk of pre-Jurassic sedimentary rocks, have been widely interpreted as marine deposits, but recently developed bulk-shale elemental proxies for palaeo-watermass salinity (i.e. B/Ga, Sr/Ba and S/TOC, where TOC is total organic carbon) have shown this inference to be frequently incorrect. Here, we use these proxies to test the salinity conditions of 22 representative shale and marl formations of early Cambrian to early Silurian age from five cratons (Laurentia, Avalonia, Baltica, Iran and South China) in the context of formation-specific palaeogeographical and palaeoclimatic reconstructions. Our dataset shows that around half of these formations were probably deposited under brackish or mixed brackish–marine conditions rather than fully marine conditions (as previously inferred), and that one of them represents a freshwater facies (previously interpreted as marine mainly on the basis of Cruziana traces). In most cases, the development of reduced-salinity conditions can be related to the coastal and/or humid climate belt setting in which the formation of interest was deposited. Our dataset also reveals systematically low Sr/Ba values (i.e. relative to modern brackish and marine facies), suggesting that seawater Sr concentrations were lower during the Early Paleozoic than at present. Our findings suggest that re-evaluation of the salinity characteristics of many ancient epicratonic shale and marl formations is necessary. Supplementary material: A supplementary figure and tables are available at https://doi.org/10.6084/m9.figshare.c.7063365 Thematic collection: This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at: https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system",
    url = "https://doi.org/10.1144/jgs2023-217",
    doi = "10.1144/jgs2023-217",
    openalex = "W4391947476",
    references = "doi101002spp21391, doi10100797894009324188, doi101016b978012824360200019x, doi101016b9780444538130000046, doi101016jprecamres2019105438, openalexw2296057071"
}