Karelids

@misc{kratz1963geology1,
    author = "Kratz, K. O",
    title = "Geology of the Karelian Karelids [in Russian]",
    year = "1963",
    howpublished = "Leningrad, Izdatel'stvo Akad. Nauk SSSR, 210 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Kratz, K. O., 1963, Geology of the Karelian Karelids [in Russian]: Leningrad, Izdatel'stvo Akad. Nauk SSSR, 210 p.}"
}

Granitic rocks ranging in composition from granite to tonalite and associated metavolcanic-metasedimentary rocks compose an east-trending belt as much as 180 km wide and 300 km long in northern Wisconsin. The granitic rocks have an initial 87Sr/ 86Sr of 0.7025 ± 0.0005 and a Rb-Sr whole-rock isochron age of 1,885 ± 65 m.y., which is interpreted as the time of crystallization of the granitic rocks. Rb-Sr whole-rock mineral secondary isochrons for two samples give ages of 1,655 ± 55 m.y. and 1,545 ± 55 m.y.; K-Ar ages of biotite from these samples are 1,615 ± 55 m.y. and 1,598 ± 54 m.y., respectively. These mineral ages are interpreted as resulting from isotopic resetting caused by a thermal event about 1,600 m.y. ago. The granitic rocks and associated metavolcanic-metasedimentary rocks constitute lower Proterozoic greenstone-granite complexes that are remarkably similar in pattern to the Archean greenstone-granite complexes in the Superior province of the Canadian Shield.

@incollection{sims1980geology,
    author = "SIMS, P. K. and PETERMAN, Z. E.",
    title = "Geology and Rb-Sr Age of Lower Proterozoic granitic rocks, northern Wisconsin",
    year = "1980",
    booktitle = "Selected Studies of Archean Gneisses and Lower Proterozoic Rocks, Southern Canadian Shield",
    abstract = "Granitic rocks ranging in composition from granite to tonalite and associated metavolcanic-metasedimentary rocks compose an east-trending belt as much as 180 km wide and 300 km long in northern Wisconsin. The granitic rocks have an initial 87Sr/ 86Sr of 0.7025 ± 0.0005 and a Rb-Sr whole-rock isochron age of 1,885 ± 65 m.y., which is interpreted as the time of crystallization of the granitic rocks. Rb-Sr whole-rock mineral secondary isochrons for two samples give ages of 1,655 ± 55 m.y. and 1,545 ± 55 m.y.; K-Ar ages of biotite from these samples are 1,615 ± 55 m.y. and 1,598 ± 54 m.y., respectively. These mineral ages are interpreted as resulting from isotopic resetting caused by a thermal event about 1,600 m.y. ago. The granitic rocks and associated metavolcanic-metasedimentary rocks constitute lower Proterozoic greenstone-granite complexes that are remarkably similar in pattern to the Archean greenstone-granite complexes in the Superior province of the Canadian Shield.",
    url = "https://doi.org/10.1130/spe182-p139",
    doi = "10.1130/spe182-p139",
    openalex = "W2410421551",
    pages = "139-146"
}

@misc{makarikhin1983phytolites2,
    author = "Makarikhin, V. V. and Kononova, G",
    title = "Phytolites of the Karelian Lower Proterozoic [in Russian]",
    year = "1983",
    howpublished = "Leningrad, Nauka, 180 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Makarikhin, V. V., and Kononova, G., 1983, Phytolites of the Karelian Lower Proterozoic [in Russian]: Leningrad, Nauka, 180 p.}"
}

@article{olson1984the,
    author = "Olson, J.M.",
    title = "The Geology of the Lower Proterozoic McCaslin Formation, Northeastern Wisconsin",
    year = "1984",
    journal = "Geoscience Wisconsin",
    url = "https://doi.org/10.54915/vdux4630",
    doi = "10.54915/vdux4630",
    openalex = "W4410995156",
    pages = "1-19",
    volume = "09"
}

This book and its companion, Early Proterozoic Geology of the Great Lakes Region (Mem. 160 Geological Society of America, 1984), edited by L.G. Medaris, Jr., are the products of an International Proterozoic symposium held at the University of Wisconsin, Madison, May 18–21, 1981. This volume contains 23 papers that present the current thinking of experts on many aspects of Proterozoic evolution of the earth; it is divided into five broad categories: tectonics, magmatism and metamorphism, mineral resources, evolution of life and the atmosphere, and glaciation. The Proterozoic is a distinctive interval in the geologic history of the earth, encompssing the transition from Archean conditions to those of the Phanerozoic. By Early Proterozoic time, extensive stable continental plates existed, and deformation, deposition, and intrusion styles were comparable to those of today. Also, the amount of free oxygen in the atmosphere and hydrosphere continuously increased during the Proterozoic and eventually reached levels supportive of metazoan evolution.

@article{sims1984proterozoic,
    author = "Sims, P K.",
    title = "Proterozoic Geology",
    year = "1984",
    journal = "Eos, Transactions American Geophysical Union",
    abstract = "This book and its companion, Early Proterozoic Geology of the Great Lakes Region (Mem. 160 Geological Society of America, 1984), edited by L.G. Medaris, Jr., are the products of an International Proterozoic symposium held at the University of Wisconsin, Madison, May 18–21, 1981. This volume contains 23 papers that present the current thinking of experts on many aspects of Proterozoic evolution of the earth; it is divided into five broad categories: tectonics, magmatism and metamorphism, mineral resources, evolution of life and the atmosphere, and glaciation. The Proterozoic is a distinctive interval in the geologic history of the earth, encompssing the transition from Archean conditions to those of the Phanerozoic. By Early Proterozoic time, extensive stable continental plates existed, and deformation, deposition, and intrusion styles were comparable to those of today. Also, the amount of free oxygen in the atmosphere and hydrosphere continuously increased during the Proterozoic and eventually reached levels supportive of metazoan evolution.",
    url = "https://doi.org/10.1029/eo065i041p00747-02",
    doi = "10.1029/eo065i041p00747-02",
    number = "41",
    openalex = "W4206357221",
    pages = "747-747",
    volume = "65"
}

The Early Proterozoic geology of Arizona and adjoining regions was the topic of a workshop convened by Clay M. Conway (U.S. Geological Survey (USGS), Flagstaff, Ariz.), Karl E. Karlstrom (Northern Arizona University (NAU), Flagstaff), and Leon T. Silver (California Institute of Technology (Caltech), Pasadena) in Flagstaff, October 3–5, 1985. The meeting, sponsored by USGS, NAU, Caltech, and the Arizona Geological Survey, was attended by 73 geologists from industry, academia, and governmental agencies. The workshop brought together for the first time workers in a variety of disciplines who have been studying facets of Early Proterozoic crustal evolution in the southwest. From responses during and following the workshop, we judge that the meeting successfully accomplished its objective of furthering communication, cooperation, and collaboration. The meeting encouraged contributions, including progress reports, from all participants and concentrated on specific problems of stratigraphy, structure, petrology, geochemistry, and ore formation, with a view toward understanding overall orogenic evolution and continental accretion.

@article{conway1986early,
    author = "Conway, Clay M. and Karlstrom, Karl E.",
    title = "Early Proterozoic geology of Arizona",
    year = "1986",
    journal = "Eos, Transactions American Geophysical Union",
    abstract = "The Early Proterozoic geology of Arizona and adjoining regions was the topic of a workshop convened by Clay M. Conway (U.S. Geological Survey (USGS), Flagstaff, Ariz.), Karl E. Karlstrom (Northern Arizona University (NAU), Flagstaff), and Leon T. Silver (California Institute of Technology (Caltech), Pasadena) in Flagstaff, October 3–5, 1985. The meeting, sponsored by USGS, NAU, Caltech, and the Arizona Geological Survey, was attended by 73 geologists from industry, academia, and governmental agencies. The workshop brought together for the first time workers in a variety of disciplines who have been studying facets of Early Proterozoic crustal evolution in the southwest. From responses during and following the workshop, we judge that the meeting successfully accomplished its objective of furthering communication, cooperation, and collaboration. The meeting encouraged contributions, including progress reports, from all participants and concentrated on specific problems of stratigraphy, structure, petrology, geochemistry, and ore formation, with a view toward understanding overall orogenic evolution and continental accretion.",
    url = "https://doi.org/10.1029/eo067i037p00681",
    doi = "10.1029/eo067i037p00681",
    number = "37",
    openalex = "W2118908097",
    pages = "681-682",
    volume = "67"
}

@article{cowie1986proterozoic,
    author = "Cowie, J.W.",
    title = "Proterozoic geology: Selected papers from an international proterozoic symposium",
    year = "1986",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/0012-8252(86)90009-7",
    doi = "10.1016/0012-8252(86)90009-7",
    number = "1",
    openalex = "W1983650055",
    pages = "67-68",
    volume = "23"
}

@article{crossref1986proterozoic,
    title = "Proterozoic geology",
    year = "1986",
    journal = "Precambrian Research",
    url = "https://doi.org/10.1016/0301-9268(86)90079-3",
    doi = "10.1016/0301-9268(86)90079-3",
    number = "3",
    openalex = "W4242935345",
    pages = "293-295",
    volume = "31"
}

@article{karlstrom1986early,
    author = "Karlstrom, Karl E. and Conway, Clay M.",
    title = "Early Proterozoic geology of Arizona",
    year = "1986",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1986)14<625:epgoa>2.0.co;2",
    doi = "10.1130/0091-7613(1986)14<625:epgoa>2.0.co;2",
    number = "7",
    openalex = "W2055782742",
    pages = "625",
    volume = "14"
}

The bedrock of western Dubawnt Lake consists of: (1) Archean, migmatized metasedimentary rocks comprised mainly of biotite-quartz-feldspar-garnet schist, including sulphide iron-formation; (2) a mafic-to-felsic intrusive suite (the Snow Island suite), dominated by granites (2605 Ma), which accompanied the migmatization; and (3) orthoquartzite plus minor schists assigned to the Lower Proterozoic Amer Group. A pervasive, shallowly south-southwest-plunging extension lineation (L2) developed at upper greenschist facies during thrusting (D2) which involved the Amer Group and older basement rocks. L2 was folded (D3) by east-west-trending folds. D2 and D3 must predate brittle deformation at 1.84 Ga leading to Dubawnt Supergroup deposition, during the Trans-Hudson orogeny. Deformation of the Amer Group probably accompanied the east-west collision between the Slave and Churchill cratons at 2.0-1.9 Ga.

@misc{peterson1994archean,
    author = "Peterson, T D and Born, P",
    title = "Archean and Lower Proterozoic geology of western Dubawnt Lake, Northwest Territories",
    year = "1994",
    abstract = "The bedrock of western Dubawnt Lake consists of: (1) Archean, migmatized metasedimentary rocks comprised mainly of biotite-quartz-feldspar-garnet schist, including sulphide iron-formation; (2) a mafic-to-felsic intrusive suite (the Snow Island suite), dominated by granites (2605 Ma), which accompanied the migmatization; and (3) orthoquartzite plus minor schists assigned to the Lower Proterozoic Amer Group. A pervasive, shallowly south-southwest-plunging extension lineation (L2) developed at upper greenschist facies during thrusting (D2) which involved the Amer Group and older basement rocks. L2 was folded (D3) by east-west-trending folds. D2 and D3 must predate brittle deformation at 1.84 Ga leading to Dubawnt Supergroup deposition, during the Trans-Hudson orogeny. Deformation of the Amer Group probably accompanied the east-west collision between the Slave and Churchill cratons at 2.0-1.9 Ga.",
    url = "https://doi.org/10.4095/193823",
    doi = "10.4095/193823",
    openalex = "W2911143095"
}

The Jamon granite is representative of the Lower Proterozoic (1.88 Ga) oxidized A-type granites of the eastern part of the Amazonian craton. The dominant facies is a metaluminous to slightly peraluminous hornblende biotite monzogranite with K2O/Na2O between 0.8 and 1.5 and FeOt/(FeOt + MgO) between 0.8 and 0.9. In contrast to many other A-type granites, the Jamon granite is characterized by early hornblende crystallization and the presence of magnetite. Crystallization experiments were performed on glass at 300 MPa between 700 and 900°C for various melt H2O contents and for both oxidizing and reducing fO2 [NNO (nickel-nickel oxide) + 2.5 and NNO - 1.5 on average]. For NNO + 2.5 and under H2O-rich conditions, ilmenite, clinopyroxene, magnetite and hornblende are near-liquidus phases, followed by plagioclase. The orthopyroxene stability field is restricted to high temperatures and H2O contents in the melt <5 wt %. In contrast, for NNO - 1.5, magnetite and titanite are absent and orthopyroxene (never observed in the granite), clinopyroxene and ilmenite are the liquidus phases. Conditions of crystallization of amphibole, magnetite and plagioclase constrain the initial melt H2O content to between 4.5 and 6.5 wt %. Plagioclase cores crystallized from 870 to 720°C. Clinopyroxene, amphibole and biotite Fe/(Fe + Mg) values suggest fO2 around NNO + 0.5 during crystallization of the granite. The demonstration of relatively hydrous conditions and oxidizing fO2 for the Jamon granite stresses the diversity of A-type magmas in terms of H2O contents and redox states. The Jamon granite was most probably generated from oxidized Archaean igneous rocks of mafic-intermediate composition.

@article{doi101093petroj40111673,
    author = "Dall’Agnol, Roberto and Scaillet, Bruno and Pichavant, Michel",
    title = "An Experimental Study of a Lower Proterozoic A-type Granite from theEastern Amazonian Craton, Brazil",
    year = "1999",
    journal = "Journal of Petrology",
    abstract = "The Jamon granite is representative of the Lower Proterozoic (1.88 Ga) oxidized A-type granites of the eastern part of the Amazonian craton. The dominant facies is a metaluminous to slightly peraluminous hornblende biotite monzogranite with K2O/Na2O between 0.8 and 1.5 and FeOt/(FeOt + MgO) between 0.8 and 0.9. In contrast to many other A-type granites, the Jamon granite is characterized by early hornblende crystallization and the presence of magnetite. Crystallization experiments were performed on glass at 300 MPa between 700 and 900°C for various melt H2O contents and for both oxidizing and reducing fO2 [NNO (nickel-nickel oxide) + 2.5 and NNO - 1.5 on average]. For NNO + 2.5 and under H2O-rich conditions, ilmenite, clinopyroxene, magnetite and hornblende are near-liquidus phases, followed by plagioclase. The orthopyroxene stability field is restricted to high temperatures and H2O contents in the melt <5 wt \%. In contrast, for NNO - 1.5, magnetite and titanite are absent and orthopyroxene (never observed in the granite), clinopyroxene and ilmenite are the liquidus phases. Conditions of crystallization of amphibole, magnetite and plagioclase constrain the initial melt H2O content to between 4.5 and 6.5 wt \%. Plagioclase cores crystallized from 870 to 720°C. Clinopyroxene, amphibole and biotite Fe/(Fe + Mg) values suggest fO2 around NNO + 0.5 during crystallization of the granite. The demonstration of relatively hydrous conditions and oxidizing fO2 for the Jamon granite stresses the diversity of A-type magmas in terms of H2O contents and redox states. The Jamon granite was most probably generated from oxidized Archaean igneous rocks of mafic-intermediate composition.",
    url = "https://doi.org/10.1093/petroj/40.11.1673",
    doi = "10.1093/petroj/40.11.1673",
    openalex = "W2170736074",
    references = "cowie1986proterozoic, doi101007bf00310745, doi101007bf00374895, doi101007bf00402202, doi1010160012821x8390211x, doi101093petroj383371, doi101126science441146863, doi101127ejm930623, doi1011300091761319920200641csotat23co2, doi101180minmag197804232421, doi101180minmag199706140513, openalexw1928320224"
}

Bulk chemical data indicate the Fern Creek Formation (Early Proterozoic, Marquette Range Supergroup, Lower Chocolay Group) originated as a glacial till, resolving an old argument about the correct interpretation for diamictite-containing units within the formation. There are poor correlations among SiO 2, Al 2 O 3, and K 2 O, and the chemical index of alteration averages 55. These are qualities characteristic of tills and other sediments accumulated in the absence of chemical weathering and transport-induced sorting and inconsistent with an origin as a fluvial deposit (the principal alternate hypothesis). The Archean Carney Lake Gneiss might be the source for at least the lower portions of the Fern Creek Formation. Compositions are similar, and rare earth element trends in the Fern Creek Formation are consistent with derivation from an Archean high-grade terrane. Pegmatites in the gneiss could be the source for monazite, huttonite, and an unnamed fluor-hydroxy-rare earth mineral that occurs in the midsection of the Fern Creek Formation. In addition, mineral and bulk chemical trends are consistent with models involving deep erosion of a complex Archean source, similar to models previously developed for Gowganda tills in the Huronian Supergroup. Samples of the Sturgeon River Quartzite occurring above the Fern Creek Formation were also analyzed. The bulk chemistry is consistent with a well-sorted, supermature quartz arenite.

@article{doi101139e01086,
    author = "Argast, Anne S.",
    title = "The lower Proterozoic Fern Creek Formation, northern Michigan: mineral and bulk geochemical evidence for its glaciogenic origin",
    year = "2002",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Bulk chemical data indicate the Fern Creek Formation (Early Proterozoic, Marquette Range Supergroup, Lower Chocolay Group) originated as a glacial till, resolving an old argument about the correct interpretation for diamictite-containing units within the formation. There are poor correlations among SiO 2, Al 2 O 3, and K 2 O, and the chemical index of alteration averages 55. These are qualities characteristic of tills and other sediments accumulated in the absence of chemical weathering and transport-induced sorting and inconsistent with an origin as a fluvial deposit (the principal alternate hypothesis). The Archean Carney Lake Gneiss might be the source for at least the lower portions of the Fern Creek Formation. Compositions are similar, and rare earth element trends in the Fern Creek Formation are consistent with derivation from an Archean high-grade terrane. Pegmatites in the gneiss could be the source for monazite, huttonite, and an unnamed fluor-hydroxy-rare earth mineral that occurs in the midsection of the Fern Creek Formation. In addition, mineral and bulk chemical trends are consistent with models involving deep erosion of a complex Archean source, similar to models previously developed for Gowganda tills in the Huronian Supergroup. Samples of the Sturgeon River Quartzite occurring above the Fern Creek Formation were also analyzed. The bulk chemistry is consistent with a well-sorted, supermature quartz arenite.",
    url = "https://doi.org/10.1139/e01-086",
    doi = "10.1139/e01-086",
    openalex = "W2053992285",
    references = "doi103133pp1241f"
}

Jurassic kimberlites in the southern Superior Province in northern Michigan contain a variety of possible lower-crustal xenoliths, including mafic garnet granulites, rare garnet-free granulites, amphibolites and eclogites. Whole-rock major-element data for the granulites suggest affinities with tholeiitic basalts. P–T estimates for granulites indicate peak temperatures of 690–730°C and pressures of 9–12 kbar, consistent with seismic estimates of crustal thickness in the region. The granulites can be divided into two groups based on trace-element characteristics. Group 1 granulites have trace-element signatures similar to average Archean lower crust; they are light rare earth element (LREE)-enriched, with high La/Nb ratios and positive Pb anomalies. Most plot to the left of the geochron on a 206Pb/204Pb vs 207Pb/204Pb diagram, and there was probably widespread incorporation of Proterozoic to Archean components into the magmatic protoliths of these rocks. Although the age of the Group 1 granulites is not well constrained, their protoliths appear to be have been emplaced during the Mesoproterozoic and to be older than those for Group 2 granulites. Group 2 granulites are also LREE-enriched, but have strong positive Nb and Ta anomalies and low La/Nb ratios, suggesting intraplate magmatic affinities. They have trace-element characteristics similar to those of some Mid-Continent Rift (Keweenawan) basalts. They yield a Sm–Nd whole-rock errorchron age of 1046 ± 140 Ma, similar to that of Mid-Continent Rift plume magmatism. These granulites have unusually radiogenic Pb isotope compositions that plot above the 207Pb/204Pb vs 206Pb/204Pb growth curve and to the right of the 4·55 Ga geochron, and closely resemble the Pb isotope array defined by Mid-Continent Rift basalts. These Pb isotope data indicate that ancient continental lower crust is not uniformly depleted in U (and Th) relative to Pb. One granulite xenolith, S69-5, contains quartz, and has a unique peraluminous composition. It has the lowest εNd and εHf values of the suite. Its isotopic compositions indicate that it is significantly older than the other granulites. Broken zircon cores encased by younger overgrowths suggest that this granulite includes a large component of pre-existing sedimentary rocks. Two distinct populations of zircons from S69-5 were dated by sensitive high-resolution ion microprobe. Abundant rounded zircons yield ages of 1104 ± 42 (2σ) Ma, which coincide with the Mid-Continent Rift flood basalt eruptions. Their morphology is similar to those found in lower-crustal rocks that have undergone granulite-facies metamorphism and thus they are considered to represent the age of Group 2 granulites. Also present are less abundant elongate zircon grains that yield a mean age of 1387 ± 32 (2σ) Ma. Their elongate shapes indicate growth from a melt or fluid, possibly associated with 1·3–1·5 Ga anorogenic granite magmatism exposed in the shallow crust to the south in Wisconsin, or related to an initial encroachment of the Keweenawan plume upon the lower crust. Older ages recognized in zircon cores are less well constrained but may be related to tectono-magmatic events in the southern Superior craton. Within the studied suite only S69-5 was recognized as a remnant of the Late Archean lower crust into which the Group 1 and 2 mafic granulite precursor basalts were intruded. Collectively, the data show that the lower crust beneath northern Michigan formed in Archean times and underwent a variety of tectono-magmatic processes throughout the Proterozoic, including orogenesis, partial melting and mafic magmatic underplating in response to upwelling mantle plumes.

@article{doi101093petrologyegs079,
    author = "Zartman, Robert E. and Kempton, Pamela D. and Paces, James B. and Downes, Hilary and Williams, Ian S. and Dobosi, G. and Futa, Kiyoto",
    title = "Lower-Crustal Xenoliths from Jurassic Kimberlite Diatremes, Upper Michigan (USA): Evidence for Proterozoic Orogenesis and Plume Magmatism in the Lower Crust of the Southern Superior Province",
    year = "2012",
    journal = "Journal of Petrology",
    abstract = "Jurassic kimberlites in the southern Superior Province in northern Michigan contain a variety of possible lower-crustal xenoliths, including mafic garnet granulites, rare garnet-free granulites, amphibolites and eclogites. Whole-rock major-element data for the granulites suggest affinities with tholeiitic basalts. P–T estimates for granulites indicate peak temperatures of 690–730°C and pressures of 9–12 kbar, consistent with seismic estimates of crustal thickness in the region. The granulites can be divided into two groups based on trace-element characteristics. Group 1 granulites have trace-element signatures similar to average Archean lower crust; they are light rare earth element (LREE)-enriched, with high La/Nb ratios and positive Pb anomalies. Most plot to the left of the geochron on a 206Pb/204Pb vs 207Pb/204Pb diagram, and there was probably widespread incorporation of Proterozoic to Archean components into the magmatic protoliths of these rocks. Although the age of the Group 1 granulites is not well constrained, their protoliths appear to be have been emplaced during the Mesoproterozoic and to be older than those for Group 2 granulites. Group 2 granulites are also LREE-enriched, but have strong positive Nb and Ta anomalies and low La/Nb ratios, suggesting intraplate magmatic affinities. They have trace-element characteristics similar to those of some Mid-Continent Rift (Keweenawan) basalts. They yield a Sm–Nd whole-rock errorchron age of 1046 ± 140 Ma, similar to that of Mid-Continent Rift plume magmatism. These granulites have unusually radiogenic Pb isotope compositions that plot above the 207Pb/204Pb vs 206Pb/204Pb growth curve and to the right of the 4·55 Ga geochron, and closely resemble the Pb isotope array defined by Mid-Continent Rift basalts. These Pb isotope data indicate that ancient continental lower crust is not uniformly depleted in U (and Th) relative to Pb. One granulite xenolith, S69-5, contains quartz, and has a unique peraluminous composition. It has the lowest εNd and εHf values of the suite. Its isotopic compositions indicate that it is significantly older than the other granulites. Broken zircon cores encased by younger overgrowths suggest that this granulite includes a large component of pre-existing sedimentary rocks. Two distinct populations of zircons from S69-5 were dated by sensitive high-resolution ion microprobe. Abundant rounded zircons yield ages of 1104 ± 42 (2σ) Ma, which coincide with the Mid-Continent Rift flood basalt eruptions. Their morphology is similar to those found in lower-crustal rocks that have undergone granulite-facies metamorphism and thus they are considered to represent the age of Group 2 granulites. Also present are less abundant elongate zircon grains that yield a mean age of 1387 ± 32 (2σ) Ma. Their elongate shapes indicate growth from a melt or fluid, possibly associated with 1·3–1·5 Ga anorogenic granite magmatism exposed in the shallow crust to the south in Wisconsin, or related to an initial encroachment of the Keweenawan plume upon the lower crust. Older ages recognized in zircon cores are less well constrained but may be related to tectono-magmatic events in the southern Superior craton. Within the studied suite only S69-5 was recognized as a remnant of the Late Archean lower crust into which the Group 1 and 2 mafic granulite precursor basalts were intruded. Collectively, the data show that the lower crust beneath northern Michigan formed in Archean times and underwent a variety of tectono-magmatic processes throughout the Proterozoic, including orogenesis, partial melting and mafic magmatic underplating in response to upwelling mantle plumes.",
    url = "https://doi.org/10.1093/petrology/egs079",
    doi = "10.1093/petrology/egs079",
    openalex = "W2154937716",
    references = "doi1010160012821x75900886, doi101016s0012821x9700040x, doi101016s0012825202000739, doi101016s0016703799003439, doi10102995rg01302, doi101111j152513141988tb00415x, doi101126science1061372, doi101144gslsp19890420119, doi105382rev0701, openalexw14108998, sims1980geology"
}

This study investigates the language contact between Tver Karelian and Russian, attempting to provide a comprehensive overview of the lexicon of bilingual code. The methodology includes a combination of statistical analyses and handling contact-induced change in terms of the Code-Copying Framework (=CCF). Nine interviews with nine people were conducted using the memory walk method. In code copying, correlations were found between different word classes and contact-relatedness. In code alternation, few differences were found between different speakers and one commonality was the use of complex numerals as Russian phrases without adapting them into the Tver Karelian code. The findings confirm that the copies are of a certain kindand appear in certain word classes. Code alternation sequences suggest that, according to the CCF, the discourse rather than the language is mixed. The findings within CCF have implications on minority language policies, as the findings support the use of bilingual terminology. Kokkuvõte. Susanna Tavi: Karjala-vene kakskeelsuse mõju tverikarjala keele sõnavarale. Käesolevas uurimistöös uuritakse tverikarjala ja vene keele kontakte. See uuring püüab anda tervikliku ülevaate kakskeelse koodi sõnavarast. Metoodika sisaldab kombinatsiooni statistilistest analüüsidest ja kontaktidest põhjustatud muutuste käsitlemisest koodikopeerimise raamistiku (Code-Copying Framework = CCF) osas. Üheksa intervjuud üheksa inimesega viidi läbi mälukõnni meetodil. Leiti seoseid erinevate sõnaklasside ja kontaktidega seotuse vahel. Koodivahelduses leiti eri kõnelejate vahel vähe erinevusi ja üheks ühiseks jooneks oli keerukate arvsõnade kasutamine venekeelsete fraasidena, ilma neid tverikarjala koodi sobitamata. Leiud kinnitavad, et koopiad on teatud liiki ja esinevad teatud sõnaklassides. Koodi vaheldumise jadad viitavad sellele, et CCF-i kohaselt on segatud eelkõige diskursus, ja mitte keel. CCF-i leiud avaldavad mõju vähemuskeelte poliitikale, kuna leiud toetavad kakskeelse terminoloogia kasutamist.

@article{tavi2022lexical,
    author = "Tavi, Susanna",
    title = "Lexical outcomes of Karelian-Russian bilingualism in Tver Karelian",
    year = "2022",
    journal = "Eesti ja soome-ugri keeleteaduse ajakiri. Journal of Estonian and Finno-Ugric Linguistics",
    abstract = "This study investigates the language contact between Tver Karelian and Russian, attempting to provide a comprehensive overview of the lexicon of bilingual code. The methodology includes a combination of statistical analyses and handling contact-induced change in terms of the Code-Copying Framework (=CCF). Nine interviews with nine people were conducted using the memory walk method. In code copying, correlations were found between different word classes and contact-relatedness. In code alternation, few differences were found between different speakers and one commonality was the use of complex numerals as Russian phrases without adapting them into the Tver Karelian code. The findings confirm that the copies are of a certain kindand appear in certain word classes. Code alternation sequences suggest that, according to the CCF, the discourse rather than the language is mixed. The findings within CCF have implications on minority language policies, as the findings support the use of bilingual terminology. Kokkuvõte. Susanna Tavi: Karjala-vene kakskeelsuse mõju tverikarjala keele sõnavarale. Käesolevas uurimistöös uuritakse tverikarjala ja vene keele kontakte. See uuring püüab anda tervikliku ülevaate kakskeelse koodi sõnavarast. Metoodika sisaldab kombinatsiooni statistilistest analüüsidest ja kontaktidest põhjustatud muutuste käsitlemisest koodikopeerimise raamistiku (Code-Copying Framework = CCF) osas. Üheksa intervjuud üheksa inimesega viidi läbi mälukõnni meetodil. Leiti seoseid erinevate sõnaklasside ja kontaktidega seotuse vahel. Koodivahelduses leiti eri kõnelejate vahel vähe erinevusi ja üheks ühiseks jooneks oli keerukate arvsõnade kasutamine venekeelsete fraasidena, ilma neid tverikarjala koodi sobitamata. Leiud kinnitavad, et koopiad on teatud liiki ja esinevad teatud sõnaklassides. Koodi vaheldumise jadad viitavad sellele, et CCF-i kohaselt on segatud eelkõige diskursus, ja mitte keel. CCF-i leiud avaldavad mõju vähemuskeelte poliitikale, kuna leiud toetavad kakskeelse terminoloogia kasutamist.",
    url = "https://doi.org/10.12697/jeful.2022.13.2.11",
    doi = "10.12697/jeful.2022.13.2.11",
    number = "2",
    volume = "13"
}

Introduction. The language situation in Russia is unique with a fair number of languages spoken on its territory and all of them having different status and scope of use. This implies the relevance of the study that focuses on the analysis of code-switching in the spoken language of the bilinguals speaking Komi and Russian and Karelian and Russian. The novelty of the study is implied by the analysis of the code-switching in the language pairs mentioned above. This contributes to the development of the code-switching theory. Methodology and sources. The methods of language data collection and processing are sociolinguistic methods of interviewing, questionnaire, observation, quantitative and descriptive methods. The research material are scripted dialogues with bilinguals as well as the “Komi mu” and “Parma gor” 2022 issues. Results and discussion. The study of the Komi-Russian and Karelian-Russian code-switching was conducted using P. Muysken’s topology of code-mixing. P. Muysken sees code-switching as alternation, insertion, and congruent lexicalization according to the degree of the foreign word assimilation in the matrix language. The features of the spoken language of the Komi-Russian bilinguals are the frequent use of Russian discursive and introductory lexical items and adverbs; the nouns and the adjectives usually following the grammatical rules of Komi; the respondents giving preference to Russian versions when using numerals. For the spoken language of the Karelian-Russian bilinguals it is typical to address to Russian vocabulary, especially when mentioning dates, numbers, and using introductory words and phrases; Russian words are also being quite easily transformed according to the Karelian grammar through its case system. Conclusion. Spontaneous speech of the bilingual interviewees contains a great number of code-switching, that could be a convincing demonstration of the language shift and is conditioned by a number of extralinguistic and linguistic factors, such as language prestige, language functionality, language situation, the native language of the interlocutor, and the willing of the respondent to use a certain language.

@article{ershov2023komi,
    author = "Ershov, A. A. and Ivanova, V. A. and Ulianitckaia, L. A.",
    title = "Komi – Russian and Karelian – Russian Code-Switching",
    year = "2023",
    journal = "Discourse",
    abstract = "Introduction. The language situation in Russia is unique with a fair number of languages spoken on its territory and all of them having different status and scope of use. This implies the relevance of the study that focuses on the analysis of code-switching in the spoken language of the bilinguals speaking Komi and Russian and Karelian and Russian. The novelty of the study is implied by the analysis of the code-switching in the language pairs mentioned above. This contributes to the development of the code-switching theory. Methodology and sources. The methods of language data collection and processing are sociolinguistic methods of interviewing, questionnaire, observation, quantitative and descriptive methods. The research material are scripted dialogues with bilinguals as well as the “Komi mu” and “Parma gor” 2022 issues. Results and discussion. The study of the Komi-Russian and Karelian-Russian code-switching was conducted using P. Muysken’s topology of code-mixing. P. Muysken sees code-switching as alternation, insertion, and congruent lexicalization according to the degree of the foreign word assimilation in the matrix language. The features of the spoken language of the Komi-Russian bilinguals are the frequent use of Russian discursive and introductory lexical items and adverbs; the nouns and the adjectives usually following the grammatical rules of Komi; the respondents giving preference to Russian versions when using numerals. For the spoken language of the Karelian-Russian bilinguals it is typical to address to Russian vocabulary, especially when mentioning dates, numbers, and using introductory words and phrases; Russian words are also being quite easily transformed according to the Karelian grammar through its case system. Conclusion. Spontaneous speech of the bilingual interviewees contains a great number of code-switching, that could be a convincing demonstration of the language shift and is conditioned by a number of extralinguistic and linguistic factors, such as language prestige, language functionality, language situation, the native language of the interlocutor, and the willing of the respondent to use a certain language.",
    url = "https://doi.org/10.32603/2412-8562-2023-9-5-167-183",
    doi = "10.32603/2412-8562-2023-9-5-167-183",
    number = "5",
    pages = "167-183",
    volume = "9"
}