Convergent boundaries and related igneous and metamorphic complexes in caledonides of Central Asia

Козаков, И. К.; Сальникова, Е. Б.; Yarmolyuk, V. V.; Kozlovsky, A. M.; Ковач, В. П.; Azimov, P. Ya.; Anisimova, I. V.; Лебедев, В. И.; Enjin, G.; Erdenejargal, Ch.; Plotkina, Yu. V.; Fedoseenko, A. M.; Yakovleva, S. Z.

doi:10.1134/s0016852112010037

Cited by 29 publications

(19 citation statements)

References 21 publications

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“…A peculiarity of spatial position of Paleozoic metamorphic belts is their con finement to an external framing of a group of Precam brian blocks. From this standpoint we can suggest that coupling of diachronous fragments of Precambrian continental crust took place in the terminal Late Riphean-Vendian, which is, for instance, evidenced by the formation of Vendian South Hangay metamor phic belt located in the inner part of the Precambrian Hangay group of blocks (Kozakov et al, 2008(Kozakov et al, , 2012. It is believed that the latter had completed as a whole its consolidation by the end of the Vendian and occurred within the Vendian-Cambrian Paleoasian ocean as a composite terrane.…”

Section: Nd Isotopic Composition Of the Magmatic And Metamorphic Rocksmentioning

confidence: 93%

“…Thus, their assignment to a single rock complex of the cover is still an open ques tion. We can believe that the consolidation of Late Precambrian units of the Dzabkhan Mandal zone and Early Precambrian complexes of DM occurred either during the Early Baikalian orogeny or later, in the Ven dian, owing to convergent processes within the Pale oasian Ocean (Kozakov et al, 2008(Kozakov et al, , 2010(Kozakov et al, , 2012). …”

Section: Nd Isotopic Composition Of the Magmatic And Metamorphic Rocksmentioning

confidence: 98%

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The Early Baikalian crystalline complex in the basement of the Dzabkhan microcontinent of the Early Caledonian orogenic area, Central Asia

Козаков

Yarmolyuk

Ковач

et al. 2012

Stratigr. Geol. Correl.

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Fragments of continental blocks or microcontinents are represented in the Early Caledonian oro genic area of Central Asia (or Early Caledonian superterrane); the largest of these are the Dzabkhan and Tuva Mongolian microcontinents, with Early and Late Precambrian crystalline basements, respectively. In the linkage zone of these microcontinents, crystalline rocks of the Tarbagatai and Songino blocks that are considered as units of the Early Precambrian ensialic basement of the superterrane are also known. They are composed of strongly metamorphosed rocks formed during the Early Baikalian orogeny about 790 to 820 Ma. U Pb zircon dating and Nd isotope studies revealed, within the northwestern Dzabkhan microcontinent, the Dzabkhan Mandal zone of crystalline rocks associated with the Riphean crust forming process. The age of the gneiss substrate of this zone is estimated as 1.3 to 0.86 Ga. An early episode of metamorphism is dated at about 856 ± 2 Ma. The data available so far indicate a heterogeneous structure of the Dzabkhan microconti nent basement represented by Early Precambrian and Early and Late Baikalian crystalline formations.

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Section: Nd Isotopic Composition Of the Magmatic And Metamorphic Rocksmentioning

confidence: 93%

Section: Nd Isotopic Composition Of the Magmatic And Metamorphic Rocksmentioning

confidence: 98%

The Early Baikalian crystalline complex in the basement of the Dzabkhan microcontinent of the Early Caledonian orogenic area, Central Asia

Козаков

Yarmolyuk

Ковач

et al. 2012

Stratigr. Geol. Correl.

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“…Центрально-Азиат-ский складчатый пояс является примером субдук-ционных и коллизионных событий, происходивших на протяжении позднего венда -раннего палеозоя между Сибирским кратоном, островными дугами и микроконтинентами. На южной окраине Сибирско-го кратона (в современных координатах) в этот пе-риод времени был сформирован Саяно-Байкальский складчатый пояс ранних каледонид, включающий гранулитовые комплексы, которые представляют собой глубоко эродированные фрагменты микро-континентов и(или) корневых частей аккреционно-коллизионных орогенов венд-раннепалеозойского возраста, то есть являются индикаторами ранних стадий закрытия Палеоазиатского океана [Kozakov et al, 2002[Kozakov et al, , 2012Dobretsov, Buslov, 2007;Volkova et al, 2008Volkova et al, , 2010Vladimirov et al, 2008Vladimirov et al, , 2011aVladimirov et al, , 2011bGladkochub et al, 2010Gladkochub et al, , 2013Donskaya et al, 2017].…”

Section: метаморфические породы чернорудской гранулитовой зоныunclassified

Mechanisms of Mantle‐crust Interaction at Deep Levels of Collision Orogens (Case of the Olkhon Region, West Pribaikalie)

Владимиров¹,

Мехоношин²,

Хромых³

et al. 2017

Geodin. tektonofiz.

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Abstract:In the Chernorud granulite zone in the Olkhon region of West Pribaikalie, we studied gabbro-pyroxenites composing tectonic plates (Chernorud, Tonta) and synmetamorphic intrusive bodies (Ulan-Khargana), as well as numerous disintegrated boudins and inclusions embedded in the metamorphic matrix. Based on the results of comparative analysis of the chemical compositions, the gabbro-pyroxenites are classified into a single island-arc tholeiitic series. The COMAGMAT software was used to simulate this series and to estimate the initial composition of the parent magma (magnesian basalt: SiO2=46.0 wt. %, TiO2=0.8 wt. %, Al2O3=15.3 wt. %, ΣFeO=9.0 wt. %, MnO=0.15 wt. %, MgO=10.5 wt. %, CaO=17.0 wt. %, Na2O=1.0 wt. %, K2O=0.2 wt. %, P2O5=0.05 wt. %, total = 100.0 %, Mg# = 67.5 %). It is concluded that the granulite metamorphism (P=7.7 to 8.6 kbar, T=770 to 820 °C) was due not only to dipping of the initial sedimentary-volcanic series to a depth of 25-28 km, but also to the presence of a deep chamber of magnesian basalt magma. In our estimations, garnet-pyroxenites (i.e. mafic rocks of the top facies in the above-mentioned chamber) originated at P=8.0-8.3 kbar and T=900-930 °C. Considering petrology, the deep mafic chamber under the layer of granulite facies is evidenced by metamorphic magma mingling, as well as pipe-shaped intrusions characterized by the specific morphology, internal structure and bulk rock compositions. Based on the data on the Ulan-Khargana massif and gabbro-pyroxenite bodies involved in the structure of the marble melange, we propose a petrological model showing two stages of mafic injection -Stage 1: hydraulic fracturing of granulite series and the emergence of tubular structures and bodies, which are similar to kimberlite pipes or channels of different shapes; Stage 2: rising of the fluidized residual alkaline melt through the emerging 'pipes' and fractures armored by hardened zones, which is followed by metamorphic magma mingling under viscous deformation conditions. The mafic magmas intruding to the

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“…with Early Precambrian crystalline complexes devel oped in the northwestern part and Late Precambrian complexes in the southeastern part. The latters were recognized in the Tatsaingol block, where they were distinguished as the Tatsaingol complex (Kozakov et al, 2008(Kozakov et al, , 2012a. Thus, it was established that the Hangay structures contain an "agglomerate" of Early and Late Precambrian crystalline blocks.…”

Section: Introductionmentioning

confidence: 99%

Main stages in the evolution and geodynamic setting of the South Hangay metamorphic belt, Central Asia

et al. 2015

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This paper reports new geological, geochronological (U Pb method) and Sm Nd isotope geochemical data on the metamorphic and magmatic complexes of the South Hangay metamorphic belt located in the southern part of the Hangay group of the Precambrian blocks, along the junction zone between the Baidarik block and the Vendian-Late Riphean ophiolite complex of the Bayanhongor zone. A lower age limit of the early metamorphic episode of the disthene-sillimanite facies series (M 2 ) is provided by the age of 603 ± 3 Ma obtained for gabbroids of the island arc association distinguished in the Tatsaingol complex. An upper age limit is determined by granites with ages of 562 ± 2, 564 ± 5, and 571 ± 9 Ma. Later superimposed metamorphism of the andalusite-sillimanite facies series (M 2 ) was established in the southeastern part of the belt. The lower boundary of this metamorphism is constrained by the emplacement of quartz diorites at 552 ± 2 Ma, while the upper boundary is marked by postkinematic granites of the Tatsaingol pluton with an age of 545 ± 5 Ma. The protoliths of high grade metamorphic rocks contained Early and Late Precambrian rocks. The former could belong to the basement of the Baidarik block and/or its shelf, while the latter, to the rocks of the oceanic and island arc complexes of the Bayanhongor paleobasin. Virtually, the continental crust, fragments of which are represented in the Tatsaingol complex, was formed within an interval around 610-560 Ma. The final stages in the formation of the South Hangay metamorphic belt coincided with the initiation of the Vendian-Early Paleozoic paleoocenic basins, volcanic islands, and island arcs in the Early Caledonian framing of the Precambrian Hangay block structure in the Late Vendian. By the time of amal gamation of structures of the Early Caledonian superterrane of Central Asia in the Late Cambrian-Early Ordovician (500-470 Ma), an "agglomerate" of the Precambrian Hangay blocks has been already formed.

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Convergent boundaries and related igneous and metamorphic complexes in caledonides of Central Asia

Cited by 29 publications

References 21 publications

The Early Baikalian crystalline complex in the basement of the Dzabkhan microcontinent of the Early Caledonian orogenic area, Central Asia

The Early Baikalian crystalline complex in the basement of the Dzabkhan microcontinent of the Early Caledonian orogenic area, Central Asia

Mechanisms of Mantle‐crust Interaction at Deep Levels of Collision Orogens (Case of the Olkhon Region, West Pribaikalie)

Main stages in the evolution and geodynamic setting of the South Hangay metamorphic belt, Central Asia

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