scholarly journals Detrital Zircon Provenance Analysis in the Central Asian Orogenic Belt of Central and Southeastern Mongolia—A Palaeotectonic Model for the Mongolian Collage

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 880
Author(s):  
Wilfried Winkler ◽  
Denise Bussien ◽  
Munktsengel Baatar ◽  
Chimedtseren Anaad ◽  
Albrecht von Quadt
Keyword(s):  
Orogenic Belt ◽  
Detrital Zircons ◽  
Central Asian Orogenic Belt ◽  
Provenance Analysis ◽  
The South ◽  
Central Mongolia ◽  
Basin Inversion ◽  
The North ◽  
Central Asian ◽  
Sandstone Provenance

Our study is aimed at reconstructing the Palaeozoic–early Mesozoic plate tectonic development of the Central Asian Orogenic Belt in central and southeast Mongolia (Gobi). We use sandstone provenance signatures including laser ablation U-Pb ages of detrital zircons, their epsilon hafnium isotope signatures, and detrital framework grain analyses. We adopt a well-established terran subdivision of central and southeastern Mongolia. However, according to their affinity and tectonic assemblage we group them into three larger units consisting of continental basement, rift-passive continental margin and arc elements, respectively. These are in today’s coordinates: (i) in the north the late Cambrian collage from which the later Mongol-Okhotsk and the Central Mongolia-Erguna mountain ranges resulted, (ii) in the south a heterogeneous block from which the South Mongolia-Xin’gan and Inner Mongolia-Xilin belts developed, and (iii) in between we still distinguish the intra-oceanic volcanic arc of the Gurvansayhan terrane. We present a model for paleotectonic development for the period from Cambrian to Jurassic, which also integrates findings from the Central Asian Orogenic Belt in China and Russia. This mobilistic model implies an interplay of rift and drift processes, ocean formation, oceanic subduction, basin inversion, collision and suture formation in space and time. The final assemblage of the Central Asian Orogenic Belt occurred in Early Jurassic.

Proterozoic microcontinents in the western Central Asian Orogenic Belt (Kyrgyzstan and Kazakhstan): relationship with Gondwana

2020 ◽  
Author(s):  
Andrey K. Khudoley ◽  
Dmitriy V. Alexeiev ◽  
S. Andrew DuFrane
Keyword(s):  
Detrital Zircon ◽  
Orogenic Belt ◽  
Detrital Zircons ◽  
Central Asian Orogenic Belt ◽  
Significant Similarity ◽  
Widespread Occurrence ◽  
The North ◽  
Central Asian ◽  
Rfbr Grant ◽  
Detrital Zircon Ages

<p>Proterozoic microcontinents are widespread in the western part of the Central Asian Orogenic Belt, but their origin remains poorly constrained. The U-Pb dating of detrital zircons in Proterozoic rocks of the southern Kazakhstan and Kyrgyz North Tianshan elucidate depositional ages and evolution of the Precambrian basins and characterize possible links of Precambrian microcontinents in these regions with Gondwana and other cratons.</p><p>Distributions of U-Pb detrital zircon ages in 13 samples from ca 5 km thick flysch-like succession of the Talas and Malyi Karatau ranges (Ishim-Middle-Tianshan microcontinent) show significant similarity. They are characterized by a widespread occurrence of Neoproterozoic grains with peaks at ca 820-800 and 910–860 Ma, almost complete absence of Mesoproterozoic grains and distinct peaks at ca 2040–1990 and 2500–2465 Ma for Paleoproterozoic grains. Archean grains occur in small amount. Close similarity is supported by K-S test indicating that samples have the same or similar provenance, also implying rapid accumulation and similar depositional ages. Main peaks resemble those in the Tarim Craton, suggesting Tarim as likely provenance and pointing to the Gondwana affinity of the Ishim-Middle-Tianshan microcontinent.</p><p>In contrast, detrital zircon populations in 3 samples from the Neoproterozoic quartzites of the North Tianshan microcontinent are dominated by Mesoproterozoic grains ranging in age from ca 1500 to 1000 Ma and contain few Paleoproterozoic grains ca 1800-1650 Ma. Distributions of U-Pb zircon ages in all 3 samples are very similar and resemble those in the early Neoproterozoic quartzites from the Kokchetav area of northern Kazakhstan, recently reported by Kovach et al. (2017). Age peaks in these samples are very different from the ages of magmatic pulses in Gondwana and point that the North Tianshan microcontinent did not have connection with Gondwana.</p><p>The Ishim-Middle-Tianshan microcontinent was rifted out from the Gondwana in late Neoproterozoic and travelled to the north. Origin and travel paths of the North Tianshan microcontinent remain poorly constrained. Widespread occurrence of Mesoproterozoic zircons implies possible links with Baltica, North America or east Siberia, but more detailed study is required to define exact provenance. These two microcontinents welded together in the middle to late Ordovician during amalgamation of the Kazakhstan paleocontinent and were jointly incorporated in Eurasia during the late Paleozoic collisions of the Kazakhstan continent with Siberia, Baltica and Tarim.</p><p>The study was supported by RFBR grant 20-05-00252</p>

NEOPROTEROZOIC TECTONIC EVOLUTION OF THE OPHIOLITIC BAYANKHONGOR SUTURE ZONE, CENTRAL ASIAN OROGENIC BELT (CENTRAL MONGOLIA)

2019 ◽  
Author(s):  
James R. Worthington ◽  
◽  
Claire E. Bucholz ◽  
Uyanga Bold ◽  
Francis A. Macdonald ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Suture Zone ◽  
Orogenic Belt ◽  
Central Asian Orogenic Belt ◽  
Central Mongolia ◽  
Central Asian

scholarly journals New insights on the early Mesozoic evolution of multiple tectonic regimes in the northeastern North China Craton from the detrital zircon provenance of sedimentary strata

Solid Earth ◽  
2018 ◽  
Vol 9 (6) ◽  
pp. 1375-1397 ◽  
Author(s):  
Yi Ni Wang ◽  
Wen Liang Xu ◽  
Feng Wang ◽  
Xiao Bo Li
Keyword(s):  
North China Craton ◽  
North China ◽  
Early Jurassic ◽  
Orogenic Belt ◽  
Detrital Zircons ◽  
Late Triassic ◽  
Early Triassic ◽  
The South ◽  
The North ◽  
Early Mesozoic

Abstract. To investigate the timing of deposition and provenance of early Mesozoic strata in the northeastern North China Craton (NCC) and to understand the early Mesozoic paleotectonic evolution of the region, we combine stratigraphy, U–Pb zircon geochronology, and Hf isotopic analyses. Early Mesozoic strata include the Early Triassic Heisonggou, Late Triassic Changbai and Xiaoyingzi, and Early Jurassic Yihe formations. Detrital zircons in the Heisonggou Formation yield  ∼ 58 % Neoarchean to Paleoproterozoic ages and  ∼ 42 % Phanerozoic ages and were sourced from areas to the south and north of the basins within the NCC, respectively. This indicates that Early Triassic deposition was controlled primarily by the southward subduction of the Paleo-Asian oceanic plate beneath the NCC and collision between the NCC and the Yangtze Craton (YC). Approximately 88 % of the sediments within the Late Triassic Xiaoyingzi Formation were sourced from the NCC to the south, with the remaining  ∼ 12 % from the Xing'an–Mongolia Orogenic Belt (XMOB) to the north. This implies that Late Triassic deposition was related to the final closure of the Paleo-Asian Ocean during the Middle Triassic and the rapid exhumation of the Su–Lu Orogenic Belt between the NCC and YC. In contrast,  ∼ 88 % of sediments within the Early Jurassic Yihe Formation were sourced from the XMOB to the north, with the remaining  ∼ 12 % from the NCC to the south. We therefore infer that rapid uplift of the XMOB and the onset of the subduction of the Paleo-Pacific Plate beneath Eurasia occurred in the Early Jurassic.

A mid-Palaeozoic ocean–continent transition in the Mazongshan subduction–accretion complex, Beishan, NW China: new structural, chemical and age data constrain the petrogenesis and tectonic evolution

2020 ◽  
Vol 157 (11) ◽  
pp. 1877-1897 ◽  
Author(s):  
J.-X. Wang ◽  
K.-X. Zhang ◽  
Brian F. Windley ◽  
B.-W. Song ◽  
X.-H. Kou ◽  
...  
Keyword(s):  
Continental Crust ◽  
Early Carboniferous ◽  
Orogenic Belt ◽  
Central Asian Orogenic Belt ◽  
Published Data ◽  
Zircon Age ◽  
The North ◽  
Tectonic History ◽  
Central Asian ◽  
Tectonic Mélange

AbstractAccretionary orogens contain key evidence for the conversion of oceanic to continental crust. The late tectonic history and closure time of the Palaeo-Asian Ocean are recorded in the Mazongshan subduction–accretion complex in the southern Beishan margin of the Central Asian Orogenic Belt. We present new data on the structure, petrology, geochemistry and zircon U–Pb isotope ages of the Mazongshan subduction–accretion complex, which is a tectonic mélange with a block-in-matrix structure. The blocks are of serpentinized peridotite, basalt, gabbro, basaltic andesite, chert and seamount sediments within a matrix that is mainly composed of fore-arc-trench turbidites. U–Pb zircon ages of two gabbros are 454.6 ± 2.5 Ma and 434.1 ± 3.6 Ma, an andesite has a U–Pb zircon age of 451.3 ± 3.5 Ma and a tuffaceous slate has the youngest U–Pb zircon age of 353.6 ± 5.1 Ma. These new isotopic ages, combined with published data on ophiolitic mélanges from central Beishan, indicate that the subduction–accretion of Beishan in the southernmost Central Asian Orogenic Belt lasted until Late Ordovician – Early Carboniferous time. Structure and age data demonstrate that the younging direction of accretion was southwards and that the subduction zone dipped continuously to the north. Accordingly, these results record the conversion of oceanic to continental crust in the southern Beishan accretionary collage.

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