Geochronology of the Metamorphic Rocks in the Kurai Accretionary Prism (South-Eastern Gorny Altai)

Kulikova, Anna V.; Buslov, M.M.; Травин, А. В.

doi:10.5800/gt-2017-8-4-0332

Cited by 3 publications

(2 citation statements)

References 23 publications

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“…Массив имеет вытянутую форму и прослеживается на расстоянии более 20 км при ширине до 4 км. В его составе выделяются пластины гипербазитов, окруженные серпентинитовым меланжем с блоками габброидов и метаморфических пород (гранатовые амфиболиты), в том числе высоких давлений (эклогиты) [Dobretsov et al, 1992;Kulikova et al, 2017;и др. ] (рис.…”

Section: геологические особенностиunclassified

Paleogeodynamics of Magmatic and Metamorphic Processes of Formation of Ultramafic Rocks of Chagan-Uzun Massif (Ophiolites of Gorny Altai)

Симонов

Kulikova

Kotlyarov

et al. 2021

Geodin. tektonofiz.

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The Geochemical and mineralogical studies showed, that harzburgites of the Chagan-Uzun massif are restites with a degree of partial melting 15-20 %, which formed at temperatures 1520-1420 °С under the conditions of the mid-oceanic ridge and transformed during the evolution of paleooceanic structures under the influence of magmatic processes at the initial stages of subduction and manifestation of boninite magmatism. The combined use of data on the geochemistry of rare and rare earth elements, as well as on the compositions of pyroxenes, Cr-spinels, melt inclusions in Cr-spinels and computational modeling, indicates the formation of clinopyroxenites of Chagan-Uzun ophiolites at the mid-oceanic ridge during crystallization of picrite and picrobasalt melts at temperatures 1315-1245 °C and pressures 4-2 kbar. The study of amphiboles showed high metamorphic parameters of transformation of harzburgites (5.1-1.9 kbar, 820-700 °С) and clinopyroxenites (2.6-1.4 kbar and 740-680 °С) of the Chagan-Uzun massif, typical for ultrabasites from the modern mid-oceanic ridges. In general, results of comprehensive studies made it possible to determine the sequence of paleogeodynamic processes of formation of ultramafic rocks of the Chagan-Uzun massif. Initial formation of harzburgites in the course of partial melting of mantle and crystallization of clinopyroxenites in the magma chamber occurred under the conditions of the mid-oceanic ridge. At the next stage, ultramafic rocks fell within the subduction-zone initiation area, where they were exposed to the influence of boninite melts.

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Section: геологические особенностиunclassified

Paleogeodynamics of Magmatic and Metamorphic Processes of Formation of Ultramafic Rocks of Chagan-Uzun Massif (Ophiolites of Gorny Altai)

Симонов

Kulikova

Kotlyarov

et al. 2021

Geodin. tektonofiz.

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“…На геолого-геодинамических схемах в работах [Buslov et al, 2013;Kulikova et al, 2017] рассмотренные комплексы выделяются в качестве структурных элементов Курайской аккреционно-коллизионной зоны и характеризуют ранний вендско-раннеордовикский островодужный этап эволюции структур юго-востока Горного Алтая. Бонинитсодержащие комплексы Курайских офиолитов относятся к образованиям Кузнецко-Алтайской островной дуги, Чаган-Узунские офиолиты (представленные фрагментами океанической коры) входят в состав комплексов Курайского аккреционного клина, сформированного в подножии Кузнецко-Алтайской островной дуги на окраине Сибирского континента.…”

Section: горного алтаяunclassified

Boninites as a Criterion for the Geodynamic Development of Magmatic Systems in Paleosubduction Zones in Gorny Altai

Котляров¹,

Симонов²,

Сафонова³

2018

Geodin. tektonofiz.

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Ancient primary boninitic melts of the Gorny Altai (65-105 km, 1410-1590 °C) were studied from the composition of melt inclusions in clinopyroxenes. We estimated their parameters and the conditions for the onset of magma crystallization in an intermediate chamber at a depth of about 30-35 km, which appear similar to the reference boninitic magmatism of the modern Izu-Bonin island arc. A combined analysis of the composition of inclusions and clinopyroxenes from Gorny Altai boninites shows that within a range of minimum temperature values (1140-1120 °C), the crystallizing material continuously ascends from a depth of 12 to 0.6 km. The pattern is different in case of higher-temperature magmas, and three zones of pyroxene crystallization are distinguished: 18.0-13.8 km (1245-1205 °С), 12.0-3.5 km (1240-1185 °С), and 3.3-0.6 km (1185-1145 °С). Actually, these zones correspond to the intermediate deep-seated magmatic chambers typical of modern island-arc subduction zones [Dobretsov et al., 2016]. Based on the detailed study of zonal phenocrysts of clinopyroxene in boninites from the Kuray ophiolites, we established the parameters of the evolution of the ascending boninite melts. Three temperature intervals (1220-1200 °С, 1235-1210 °С, and 1120-1220 °С) and three pressure ranges (1.5-11.5 kbar, 2.0-6.0 kbar, and 2.0-0.3 kbar) are distinguished. One case shows a significant pressure drop (from 11.5 to 1.5 kbar) with a small drop in temperature (from 1220 °C to 1200 °C). In the second case, the pressure rises from 2.0 to 6.0 kbar, and the crystallization temperature decreases from 1235 to 1210°C. In the third case, crystallization begins at a stable temperature (1120-1140 °C) and a stable pressure (1.4-2.0 kbar); then, in the near-surface conditions, the temperature increases to 1220 °C, and the pressure decreases sharply to 0.3 kbar.

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Late Paleozoic tectonics of the Junggar-Altai–Sayan Foldbelt

Буслов

Cai

Abildaeva

2019

IOP Conf. Ser.: Earth Environ. Sci.

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This paper presents new tectonic model for the Late Palaeozoic evolution of the Jungar-Altai–Sayan Fold Belt in the context of large-amplitude (hundreds to several thousands of kilometres) strike-slip movement along regional NW-trending fault zones. These include the following regional fault zones: Chara, Irtysh, Northeast, Charysh–Terekta and Kurai-Teletsk, as well as the thrusts associated with them kinematically:Tangbale-Kolameili,Mayile, Barleik–Hongguleleng, Kaim, North Sayan thrust fault and Kurtushuba.

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Geochronology of the Metamorphic Rocks in the Kurai Accretionary Prism (South-Eastern Gorny Altai)

Cited by 3 publications

References 23 publications

Paleogeodynamics of Magmatic and Metamorphic Processes of Formation of Ultramafic Rocks of Chagan-Uzun Massif (Ophiolites of Gorny Altai)

Paleogeodynamics of Magmatic and Metamorphic Processes of Formation of Ultramafic Rocks of Chagan-Uzun Massif (Ophiolites of Gorny Altai)

Boninites as a Criterion for the Geodynamic Development of Magmatic Systems in Paleosubduction Zones in Gorny Altai

Late Paleozoic tectonics of the Junggar-Altai–Sayan Foldbelt

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