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- Gladkochub, Dmitry P., et al.
(author)
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Proterozoic mafic magmatism in Siberian craton: An overview and implications for paleocontinental reconstruction
- 2010
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In: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 183:3, s. 660-668
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Journal article (peer-reviewed)abstract
- We present a summary of late Paleoproterozoic to Neoproterozoic mafic magmatism in the Siberian craton, including recently published U-Pb and Ar-40-Ar-39 dates. These new precise ages suggest that at least some of the previously published K-Ar ages of Siberian mafic bodies should be ignored. The time-space geochronological chart, or the 'barcode' of mafic magmatic events shows significant differences between northern and southern Siberia. Both are characterized by similar to 1900-1700 Ma magmatic events, but then there was an almost 1 Ga mafic magmatic 'pause' in south Siberia until similar to 800 Ma. Meanwhile there are indications of multiple mafic magmatic events in North Siberia (Anabar shield and Olenek uplift) between similar to 1600 and 1000 Ma. A series of magmatic events probably related to the breakup of Rodinia occurred in southern Siberia after similar to 800 Ma. So far, there are no indications of late Neoproterozoic mafic magmatism in North Siberia. Ca. 1000-950 Ma mafic sills were reported from Meso- to Neo-Proterozoic sedimentary successions in the Sette-Daban area on the east side of the Siberian craton, but their tectonic setting is debated. Recent Ar-Ar dates of similar to 1750 Ma for NW-trending dykes in the Aldan and Anabar shields, together with similar-age NNE-trending Baikal uplift dykes in south-eastern Siberia suggest the existence of a giant radial dyke swarm possibly related to a mantle plume centred in the Vilyui River area. (C) 2010 Elsevier B.V. All rights reserved.
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- Puchkov, Victor N., et al.
(author)
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The ca. 1380 Ma Mashak igneous event of the Southern Urals
- 2013
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In: Lithos. - : Elsevier BV. - 0024-4937. ; 174, s. 109-124
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Journal article (peer-reviewed)abstract
- A review of the geochronology, geochemistry and distribution of the 1380 Ma Mashak Large Igneous Province (LIP) of the eastern margin of the East European craton indicates a potential link to a major breakup stage of the Mesoproterozoic supercontinent Columbia (Nuna), link to a major stratigraphic boundary (Lower-Middle Riphean), and economic significance for hydrocarbons and metallogeny. Specifically, the Mashak event likely has much greater extent than previously realized. Two U-Pb baddeleyite (ID TIMS) age determinations on dolerite sills obtained from borehole (Menzelinsk-Aktanysh-183) confirm the western extent of the Mashak event into the crystalline basement of the East European Craton (1382 +/- 2 Ma) and into the overlying Lower Riphean sediments (1391 +/- 2 Ma), and the imprecise ages reported elsewhere indicate the possible extension into the Timan region, with an overall areal extent of more than 500,000 km(2) (LIP scale). It has tholeiitic compositions and is associated with breakup on the eastern margin of the craton - in addition, precise SHRIMP zircon ages of 1386 +/- 5 Ma and 1386 +/- 6 Ma (this paper) provide confirmation of previous approximate 1380-1383 Ma zircon age determination of the same formation, and suggest an age of ca. 1.4 Ga for the Lower/Middle Riphean boundary which was formerly considered to be 1350 +/- 10 Ma. Contemporaneous magmatic rocks in the northeastern Greenland part of Laurentia (Zig-Zag Dal and Midsommerso formations) and Siberia (Chieress dykes and other dolerites) together with the Mashak event are suggested to be fragments of a single huge LIP and to correspond to breakup stage of the Columbia (Nuna) supercontinent. The Mashak LIP also has some significance, at least in Volgo-Uralia, for hydrocarbons and metallogeny. (C) 2012 Elsevier B.V. All rights reserved.
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- Zibra, Ivan, et al.
(author)
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Regional-scale polydiapirism predating the Neoarchean Yilgarn Orogeny
- 2020
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In: Tectonophysics. - : Elsevier BV. - 0040-1951. ; 779
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Journal article (peer-reviewed)abstract
- Gneiss domes occur in a wide variety of orogenic and anorogenic domains of the continental crust, and play a major role in lithosphere dynamics by allowing upwards transfer of heat and mass. They commonly contain a core of granites and/or migmatites, overlain by a mantle of lower-grade rocks. Evolutionary models of many gneiss domes are controversial. Here we use new structural and zircon isotopic data to unravel the tectono-magmatic evolution of the Yalgoo dome and surroundings, at the margins of the Neoarchean Yilgarn Orogen, Western Australia. The study area includes at least seven granite–migmatite domes (5–70km in average diameter), and several subdomes within the larger domes, all showing comparable structural features and age. In each dome, a concentric domal foliation is concordant with granite–greenstone contacts, bearing a radial, outward-plunging lineation. The bulk of the structures in each dome reflect magmatic flow, with pervasive subsolidus fabrics occurring only along the outer dome margins, and reflecting dome-up kinematics. Narrow greenstone keels pinched between domes and subdomes display vertical constriction, in an area regionally dominated by flattening along the steep sides of the deeply-eroded domes, and along the flat-laying dome roofs. The regional structural pattern and the kinematics of the high-strain zones are best explained by sequential emplacement of nested diapirs, which delivered large volumes of granitic magma in a c. 20Myr time-span. The dome-and-keel regional architecture and the internal structures of each dome resulted therefore from multiscale polydiapirism. These diapirs were later weakly overprinted by a tectonic fabric that developed during the Neoarchean Yilgarn Orogeny. The contrast between the Yalgoo region and the rest of the craton, which was strongly reworked by this orogeny, highlights the dichotomy of tectonic styles in Archean terranes, demonstrating that diapirism dominated in times of tectonic quiescence.
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| 7. |
- Zibra, Ivan, et al.
(author)
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Tectono-magmatic evolution of the Neoarchean Yalgoo dome (Yilgarn Craton): Diapirism in a pre-orogenic setting
- 2018
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Reports (other academic/artistic)abstract
- Gneiss domes occur in any orogenic and anorogenic domain of the continental crust, from Precambrian cratons to present-day active orogens. They commonly contain a core of granitic rocks and/or high-grade metamorphic rocks, overlain by a mantle of lower-grade rocks. Evolutionary models of many gneiss domes are controversial. We use new structural and geochronological data to constrain the tectono-magmatic evolution of the Yalgoo dome in the Yilgarn Craton of Western Australia. The granite–migmatite core of the dome shows an overall domal foliation pattern, associated with radial and outwardsplunging lineations. A high-strain zone with top-outwards sense of shear (the Badja decollément) occurs along the granite–greenstone boundary. The greenstone sequence contains an angular unconformity that likely developed during doming. We show that doming, associated with outward flow of supracrustal material, was accompanied by the emplacement of large volumes of granitic magma at 2760–2750 Ma. The dome-scale finite strain pattern resulted from diapiric granite emplacement into the greenstone cover, with negligible background regional stress. Granitic plutons flanking the Yalgoo dome show a similar, first-order structural architecture. The dome-forming fabric is locally overprinted by a discordant, north-trending foliation caused by folding that likely developed at c. 2700 Ma, during the Neoarchean Yilgarn orogeny.
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