Earth Science Frontiers ›› 2022, Vol. 29 ›› Issue (2): 115-131.DOI: 10.13745/j.esf.sf.2022.2.11

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Spatio-temporal distribution of Mesozoic volcanic strata in the Great Xing’an Range: Response to the subduction of the Mongol-Okhotsk Ocean and Paleo-Pacific Ocean

YANG Yajun(), YANG Xiaoping*(), JIANG Bing, WANG Yan, PANG Xuejiao   

  1. Shenyang Center of Geological Survey, China Geological Survey, Shenyang 110034, China
  • Received:2021-08-12 Revised:2021-10-14 Online:2022-03-25 Published:2022-03-31
  • Contact: YANG Xiaoping

Abstract:

To improve the regional comparability of Mesozoic volcanic rock strata in the Great Xing’an Range region, we examined in-depth the tectonic relationship between the volcanic rock strata and the Paleo-Pacific/Mongol-Okhotsk Plates. By mapping (1: 1 million) the Great Xing’an Range region, combined with data on rock association, paleontology, contact relationship and regional comparison, as well as the latest zircon chronology (through U-Pb,40Ar/39Ar zircon dating), we redefined the Mesozoic volcanic strata of the Great Xing’an Range region, and subsequently further defined the formation periods of the Tamulangou (172-161 Ma), Manketouebo (162-148 Ma), Manitu (158-145 Ma), Baiyingaolao (145-129 Ma), Meiletu (143-128 Ma), Longjiang (128-121 Ma), Guanghua (128-118 Ma), Ganhe (120-113 Ma) and Gushanzhen (118-110 Ma) Formations. Together with the spatial distribution analysis of volcanic strata, taking into account the subduction of the Paleo-Pacific and Mongol-Okhotsk Plates at the continental margin of East Asia, the tectonic setting of the Mesozoic volcanic rock strata was analyzed. We found that the NE-trending volcanic rock strata of the Middle-Late Jurassic mainly formed in the extensional tectonic setting associated with the southward subduction of the Mongol-Okhotsk Plate, while the NNE-trending volcanic rock strata of the Early Cretaceous mainly formed in the extensional tectonic setting associated with the subduction of the Izenaki Plate beneath the East Asian continent. The molasse-like deposits in the Kaikukang and Murui Formations, developed between the Late Jurassic-Early Cretaceous volcanic strata, are the main sedimentary record of the transition stage between the two tectonic domains.

Key words: Great Xing’an Range, Mesozoic volcanic rock strata, temporal-spatial distribution, Paleo-Pacific Ocean, Mongol-Okhotsk Ocean

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