Early Stage of the Central Asian Orogenic Belt Building: Evidences From the Southern Siberian Craton

Гладкочуб, Д.П.; Donskaya, T. V.; Zhang, Shihong; Pisarevsky, Sergei A.; Stanevich, A. M.; Мазукабзов, А. М.; Motova, Z.L.

doi:10.5800/gt-2017-8-3-0262

Cited by 3 publications

(4 citation statements)

References 8 publications

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“…A detailed geochemistry and geochronology study by Donskaya et al (2017) allowed for further interpretation of the pre‐collisional architecture of the Olkhon Terrane as a collage of continental and oceanic units of Paleoproterozoic, Neoproterozoic, and early Paleozoic age. All of these have been metamorphosed during the early Paleozoic Baikal orogenic cycle (c. 450–510 Ma) (Gladkochub, Donskaya, Sklyarov, et al, 2017), which is additionally associated with the widespread intrusion of chemically diverse igneous rocks (Donskaya et al, 2017; Donskaya, Gladkochub, Fedorovsky, et al, 2013; Gladkochub, Donskaya, Wingate, et al, 2008; Mekhonoshin et al, 2013; Mikheev et al, 2017).…”

Section: Geological Settingmentioning

confidence: 99%

Metamorphic and chronological constraints on the early Paleozoic tectono‐thermal evolution of the Olkhon Terrane, southern Siberia

Jiang

Collett

et al. 2023

Journal Metamorphic Geology

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Terranes accreted to the southeastern margin of the Siberian Craton record an important early Paleozoic tectono-thermal event (known as the Baikal orogenic cycle) in the evolution of the Central Asian Orogenic Belt (CAOB). However, the precise metamorphic conditions and relative timing of this event and its linkage to the wider CAOB remain far poorly constrained. The best exposed of these terranes is the Olkhon Terrane on the western bank of Lake Baikal.Here, late Neoproterozoic through early Paleozoic island arc and back-arc assemblages were metamorphosed to form a thin granulite facies belt cropping out adjacent to the Siberian Craton and lower temperature/pressure paragneiss and migmatite towards the southeast. Phase equilibria modelling suggests that the granulite facies belt preserved moderate pressure (c. 0.80 GPa) and high temperature (up to 900 C) conditions while the paragneiss and migmatites in the southeast have peak metamorphic conditions around 700-770 C at 0.60-0.80 GPa. New geochronological data (zircon U-Pb in granulite and monazite U-Pb in paragneiss/migmatite) in combination with phase equilibria modelling and petro-structural analysis suggest that the tectono-metamorphic evolution of the Olkhon Terrane was controlled by a long-lasting (535-450 Ma) and pervasive thermal anomaly. Discrete maxima in the zircon and monazite U-Pb ages at c. 535, 500, and 450 Ma are linked to different stages of a semi-continuous high-temperature metamorphic evolution. Based on existing geological data of the region, a generalized geodynamic model for the Baikal orogenic cycle involving switching between compressional and extensional regimes during the early Paleozoic accretion of 'exotic' CAOB-derived material to the southern margin of Siberia is proposed. The tectono-metamorphic evolution of the Olkhon Terrane may represent a worldclass example of polyphase shortening of a long-lived hot intra-continental arc-back-arc system during its collision with cratonic blocks.

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Section: Geological Settingmentioning

confidence: 99%

Metamorphic and chronological constraints on the early Paleozoic tectono‐thermal evolution of the Olkhon Terrane, southern Siberia

Jiang

Collett

et al. 2023

Journal Metamorphic Geology

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“…Whole-rock ε Nd (t) values for the paragneiss vary from −3.2 to −9.6, and their corresponding T DM model ages are 1.5-2.1 Ga (Donskaya et al, 2017;Gladkochub et al, 2008b;Makrygina et al, 2014). The geochemical compositions of these rocks are comparable with immature greywackes deposited in a back-arc basin setting (Gladkochub et al, 2017). Granitic gneiss in this zone are characterized by LREE enrichment and negative Eu anomalies and are often interpreted as syntectonic leucogranite dykes that intruded the Anga-Sakhurta Zone at c. 470-458 Ma and were gneissified parallel to host rock fabric (Vladimirov et al, 2011).…”

Section: Geological Settingmentioning

confidence: 82%

Peri‐Siberian Ordovician to Devonian Tectonic Switching in the Olkhon Terrane (Southern Siberia): Structural and Geochronological Constraints

Li,

Jiang,

Collett

et al. 2023

Tectonics

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The Olkhon Terrane is thought to preserve a record of the initial collision of the Siberian Craton with its peripheral orogenic system during the early Paleozoic. However, the related tectono‐metamorphic process and its time‐scale remain obscure. To address this issue, new structural observations combined with U‐Pb zircon and monazite and 40Ar/39Ar biotite geochronology were conducted in the migmatitic‐granitic Anga‐Sakhurta Zone of the terrane. An earliest syn‐collisional event associated with the development of a c. 500–480 Ma sub‐horizontal migmatitic fabric is confirmed. This early fabric was affected by later extensional doming in association with emplacement of partial melts (in terms of c. 470–445 Ma granite sills) parallel to the sub‐horizontal mechanical anisotropy. Subsequent upright folding leading to amplification of extensional domal structures and heterogeneous vertical transposition of composite horizontal fabric occurred soon after the doming, as indicated by intrusions of residual melts into the axial planes of the upright folds. The latest episode of deformation was marked by development of greenschist‐facies sinistral shear zones surrounding the Anga‐Sakhurta Zone at c. 420–400 Ma. An updated tectonic model involving (a) Middle–Late Ordovician crustal thinning associated with horizontal crustal flow, (b) Silurian crustal shortening related to northwards movement of Cambrian magmatic arc of the Birkhin Complex to the south, and (c) Early Devonian lateral extrusion and sinistral shearing associated with progression of the Birkhin Complex promontory, is proposed. Results from this study shed lights on the collisional evolution of peri‐Siberian orogenic system during the early stage evolution of the Central Asian Orogenic Belt.

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“…Это сооружение возникло в результате причленения к южному краю фундамента Сибирской платформы неопротерозойского композитного супертеррейна, образованного в результате аккреции фрагментов активных континентальных окраин, островных дуг, микроконтинентов, существовавших в Мировом и Палеоазиатском океанах (рис. 11, а) [Gladkochub et al, 2013[Gladkochub et al, , 2019. В современной структуре северного сегмента Центрально-Азиатского складчатого пояса вблизи краевой части Сибирской платформы в виде не полностью разрушенного остатка этого крупного неопротерозойского композитного супертеррейна можно рассматривать Байкало-Муйский пояс [Rytsk et al, 2007;Powerman et al, 2015;Gladkochub et al, 2019], а в виде отдельных раздробленных сегментов этого супертеррейна -фрагменты докембрийских и неопротерозойских комплексов пород в Западном Забайкалье [Ruzhentsev et al, 2012] и Приольхонье [Donskaya et al, 2017].…”

Section: обсуждение результатовunclassified

“…В современной структуре северного сегмента Центрально-Азиатского складчатого пояса вблизи краевой части Сибирской платформы в виде не полностью разрушенного остатка этого крупного неопротерозойского композитного супертеррейна можно рассматривать Байкало-Муйский пояс [Rytsk et al, 2007;Powerman et al, 2015;Gladkochub et al, 2019], а в виде отдельных раздробленных сегментов этого супертеррейна -фрагменты докембрийских и неопротерозойских комплексов пород в Западном Забайкалье [Ruzhentsev et al, 2012] и Приольхонье [Donskaya et al, 2017]. Предполагается, что окончательное присоединение этого крупного неопротерозойского композитного супертеррейна к краю платформы имело место на временном рубеже 600-610 млн лет [Ruzhentsev et al, 2012;Powerman et al, 2015;Gladkochub et al, 2019] и фиксируется серией магматических пород в Байкало-Муйском поясе [Izokh et al, 1998;Amelin et al, 2000;Rytsk et al, 2004Rytsk et al, , 2007Rytsk et al, , 2011Rytsk et al, , 2017Fedotova et al, 2014;Somsikova et al, 2021]. Снос материала с этого супертеррейна в сторону платформы, а именно в бассейн форланда и в последующем во внутриконтинентальный (предгорный) бассейн, обеспечил поступление неопротерозойских цирконов в осадочные толщи этих бассейнов, а снос непосредственно с фундамента платформы способствовал добавлению докембрийских цирконов в бассейны седиментации (рис.…”

Section: обсуждение результатовunclassified

METATERRIGENIOUS ROCKS OF THE OLKHON TERRANE OF THE CENTRAL ASIAN OROGENIC BELT: U-Pb ZIRCON AGE, GEOCHEMICAL CHARACTERISTICS, AND FORMATION MODELS OF SEDIMENTARY PROTOLITHS

Donskaya

Гладкочуб

Мазукабзов

et al. 2022

Geodin. tektonofiz.

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The paper presents a petrographic, geochemical, and Sm-Nd isotopic data on the gneisses from different tectonic zones of the Olkhon terrane of the Central Asian Orogenic Belt, as well as the composition of garnets and the age of zircons in these metaterrigenous rocks. The garnet-biotite gneisses of the Anga-Sakhurta zone, as well as the garnet-bearing and garnet-free gneisses (granulites) of the Chernorud zone may result from metamorphism of immature terrigenous rocks of polymictic or greywacke compositions similar in geochemical characteristics to rocks of continental arcs. At the same time, the gneisses of these zones show both similarities and some differences in geochemical and isotopic characteristics, including variations in ɛNd(T) values from –0.2 to –9.0, which may indicate different proportions of one or another source in their protoliths. The age of most detrital zircons in the gneisses of the Chernorud and Anga-Sakhurta zones corresponds to 530–1000 Ma, and the youngest detrital zircons have an age of 522–537 Ma. The geochemical and geochronological data on the gneisses of the Chernorud and Anga-Sakhyurta zones suggests that the protoliths of these gneisses could be formed from the same sources of predominantly Neoproterozoic age. We assumed that gneiss protoliths could initially be sediments of the continental slope of Neoproterozoic composite terrane assembled to the Siberian Platform at 600‒610 Ma. The transport of clastic material being gneiss protoliths from this composite terrane, took place towards the Paleo-Asian Ocean. The youngest zircons with an age of about 530 Ma could be generated from igneous complexes intruding the Neoproterozoic composite superterrane. The garnet-biotite gneisses of the Krestovskaya zone are similar in chemical composition to immature graywacke sandstones, The ɛNd(T) value in these gneisses is –3.7. Detrital zircons in the gneisses of the Krestovskaya zone form age peaks at 780–820 and 498–515 Ma. Based on geochemical and geochronological data we assume that these gneisses could be formed in an intracontinental basin formed at the orogenic stage during accretionary-collisional events at the amalgamation the Orso block and the Birkhin island arc into the Krestovskaya zone.All terrigenous rocks being gneiss protoliths were metamorphosed at 460–510 Ma under granulite or amphibolite facies associated with accretionary and collisional events, which led to the formation of the Early Paleozoic Olkhon composite terrane.

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Early Stage of the Central Asian Orogenic Belt Building: Evidences From the Southern Siberian Craton

Cited by 3 publications

References 8 publications

Metamorphic and chronological constraints on the early Paleozoic tectono‐thermal evolution of the Olkhon Terrane, southern Siberia

Metamorphic and chronological constraints on the early Paleozoic tectono‐thermal evolution of the Olkhon Terrane, southern Siberia

Peri‐Siberian Ordovician to Devonian Tectonic Switching in the Olkhon Terrane (Southern Siberia): Structural and Geochronological Constraints

METATERRIGENIOUS ROCKS OF THE OLKHON TERRANE OF THE CENTRAL ASIAN OROGENIC BELT: U-Pb ZIRCON AGE, GEOCHEMICAL CHARACTERISTICS, AND FORMATION MODELS OF SEDIMENTARY PROTOLITHS

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