Neoproterozoic intraplate magmatism along the western margin of the Siberian Craton: Implications for breakup of the Rodinia supercontinent

Лиханов, И. И.; Santosh, M.

doi:10.1016/j.precamres.2017.08.019

Cited by 48 publications

(18 citation statements)

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“…Metapelite samples used in this study were collected within the GC in the lower course of the Tis (sample 58 – 59°36′21.9N, 91°09′42.99E) and Garevka River (sample 27 – 59°51′10.5N, 90°49′36E) and from outcrops on the right bank of the Yenisey River (sample 56 – 59°16′48.5N, 91°20′29.2E) (Figure ). The metapelitic rocks of the study area are Grt + Bt + Ms + Pl + And + Ky ± Sil + Qz ± St ± Ilm ± Chl ± Ep intensely deformed gneisses and schists crosscut by steeply dipping, sheeted, coarse‐grained felsic dykes (Likhanov & Santosh, ).…”

Section: Geological Backgroundmentioning

confidence: 99%

The ‘triple point’ paradigm of aluminosilicates revisited

Лиханов

Santosh

2019

Geological Journal

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The Al 2 SiO 5 polymorphs (andalusite, kyanite and sillimanite), which are dominant constituents in aluminous metamorphic rocks, are gaining increasing importance as industrial sources for aluminium oxide, silumin and aluminium. The formation of the most promising deposits and occurrences of the Al-rich rocks in the Transangarian segment of the Yenisei Ridge of the Siberian Craton are genetically related to the metamorphism of the And-Sil and Ky-Sil types. Reaction microtextures, chemical zoning in minerals, radiometric dating as well as the Р-Т trajectories of these rocks provide evidence for the polymetamorphic history of the aluminosilicate triple-point assemblages (containing all three Al 2 SiO 5 minerals). The metapelites with highly aluminous bulk compositions in the Yenisey Ridge record overprinting of early mineral assemblages during subsequent thermal events. The triple-point positions reported in earlier studies resulted from polymetamorphism (asynchronous growth of the polymorphs), when all aluminium-silicate minerals grew at different times in the metamorphic history of the rock and hence cannot be regarded as true triple-point parageneses, notwithstanding the possibility that parts of the looping P-T paths may have passed near the triple point. The occurrence of all three Al 2 SiO 5 minerals in individual rocks was interpreted to be due to reaction relations with microtextural evidence of one polymorph replacing another. We illustrate that the aluminium silicate triple-point assemblages, in which all three Al 2 SiO 5 minerals are in stable equilibrium, are not possible in metapelitic rocks of a wide range of chemical composition. Hence such purported triple-point assemblages cannot represent a stable association and cannot be used to calibrate or test geothermobarometers. K E Y W O R D S Al 2 SiO 5 minerals, Al-rich metapelites, triple point, polymetamorphism, Yenisei Ridge, Siberian Craton 1 | INTRODUCTION The polymorphic modifications of Al 2 SiO 5 , namely kyanite, andalusite and sillimanite, are among the most important indicators of metamorphism in pelitic lithologies. Having the same chemical composition, they are characterized by different crystal structures stable at different P-Tconditions. Based on various trends of the evolution of temperature with depth and the relationships between these trends on the P-T diagram with the stability fields of Al 2 SiO 5 polymorphs, different 'baric' types of metamorphism are distinguished (for example, Miyashiro, 1961;Reverdatto, Likhanov, Polyansky, & Sheplev, 2019). Thus, andalusite is stable at low pressures and temperatures; with pressure increase, it is replaced by kyanite, and with temperature increase, andalusite and kyanite are replaced by sillimanite, resulting in the formation of zoned metamorphic complexes of low and moderate pressures. These conditions are mostly located in part of P-T space traversed by many crustal metamorphic sequences, so that inferences about P-T conditions can be made based on the occurrence of one or more of the polymor...

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Section: Geological Backgroundmentioning

confidence: 99%

The ‘triple point’ paradigm of aluminosilicates revisited

Лиханов

Santosh

2019

Geological Journal

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“…Химических состав минеральных фаз определен на рентгеноспектральном микроанализаторе Jeol-JXA-8100 в ИГМ СО РАН с использованием стандартных процедур, описанных в (Likhanov, Santosh, 2017).…”

Section: методы исследованияunclassified

Sapphirine-bearing granulites of the anabar shield

et al. 2019

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The results of a detailed study of the mineral and chemical composition, geothermobarometry, and U-Pb isotope dating of zircon of high-aluminous sapphirine-bearing crystals of shales associated with biotite-garnet-sillimanite gneisses, hypersthene-two feldspar and high-potassium hypersthene orthogneisses, Ti-rich and subalkaline metabasites belonging to the Kilegirian Formation of the Daldyn series of the Anabar shield. Unlike the known granulites of the Daldin and Upper Ananbar series, the rocks of this association are enriched in K, Rb, Ba, Th, light REEs, differing in elevated (La/Yb)n. The results of thermobarometry yielded the P–Tparameters of formation and evolution of sapphirine-bearing granulites in the Anabar shield with peak values of UHT metamorphism in the range of T= 920–1000°C at P= 9–11 kbar. Isotope-geochronological data indicate a polymetamorphic evolution of these rocks. Detrital zircon cores in the center of crystals yielded ages of 3.36, 2.75, 2.6, and 2.5 Ga. Later, superimposed metamorphic transformations of the detrital zircon formed rims dated to 2.4, 2.3, 2.2, and 1.8 Ga. The timing of formation of aluminous metasedimentary and associated metamagmatic rocks can be estimated in the interval from 2.5 to 2.4 billion years. A potential provenance source of the detrital zircons could be hypersthene plagiogneisses and metabasites of the Daldyn series with a premetamorphic age no less than 3.3 Ga, and products of their metamorphism of about 2.7 Ga old, and possibly not yet detected in the region Na-K granites with an age of about 2.6–2.5 billion years, known on other shields and enriched with radioactive (K, Th, U) and rare elements. An additional source of clastic material in the formation of aluminous sediments could be the associated two feldspar magmatic rocks of rhyolite composition, having the same model age with them.

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“…2, рис. 1) в пределах аналитической погрешности [78,79]. Подобные вариации давления могли быть вызваны интенсивной сдвиговой деформацией в неоднородной среде, что предполагает тектонический контроль поздней стадии метаморфизма.…”

Section: р-т тренды метаморфизма и P-t-x псевдосеченияunclassified

Приразломные тектониты Енисейского кряжа. Статья 2: P-T-t-d эволюция и геодинамические модели формирования

Лиханов¹,

Крылов²,

Ренье³

2018

geology

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В пределах Приенисейской региональной сдвиговой зон ы Енисейского кряжа изучены метапелиты и метабазиты, подвергшиеся интенсивным деформациям c перекристаллизацией субстрата и образованием тектонитов. Выявленные различия в Р-Т параметрах метаморфизма между сильно- и слабодеформированными породами и конфигурации P-T-t-d трендов, рассчитанные с использованием минеральной геотермобарометрии и псевдосечений в системе NCKFMASH, обсуждены в рамках геодинамических моделей, контролируемых разными тектоническими механизмами. Полихронный динамометаморфизм гнейсов Ангаро-Канского блока на юге и формирование основной массы бластомилонитов северного сегмента ПРСЗ происходили с повышением давления на 1,5–3 кбар при незначительном увеличении температуры с низким метаморфическим градиентом dT/dH <10°С/км в сравнении с фоновыми значениями более раннего регионального метаморфизма, что вероятно было обусловлено утолщением земной коры в результате быстрого надвига/субдукции с последующим быстрым подъемом пород. Максимальные превышения термодинамических параметров метаморфизма установлены в тектонитах базитового состава с реликтовыми глаукофансланцевыми ассоциациями, которые подверглись метаморфизму с одновременным значительным ростом давления на 3–5 кбар и температуры на 180–240°С при более высоком градиенте dT/dH=15–20°С/км. Такие превышения Р-Т параметров могли быть связаны с прогрессивным метаморфизмом, осложненным локальным разогревом пород при вязких деформациях и превышением ориентированного тектонического давления над литостатическим в зонах пластического сдвига. Полученные данные хорошо согласуются с результатами численных экспериментов, что подтверждает представления о роли тектонического стресса как дополнительного термодинамического фактора метаморфических преобразований в шовных зонах земной коры.

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Neoproterozoic intraplate magmatism along the western margin of the Siberian Craton: Implications for breakup of the Rodinia supercontinent

Cited by 48 publications

References 122 publications

The ‘triple point’ paradigm of aluminosilicates revisited

The ‘triple point’ paradigm of aluminosilicates revisited

Sapphirine-bearing granulites of the anabar shield

Приразломные тектониты Енисейского кряжа. Статья 2: P-T-t-d эволюция и геодинамические модели формирования

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