Deformation patterns and timing of the thrust‐nappe structures in the Mohe Formation in Mohe Basin, Northeast China: Implication of the closure timing of Mongol–Okhotsk Ocean

Abstract

The Mohe Basin, to the south of the eastern Mongol–Okhotsk suture belt, contains important stratigraphic records and thrust‐nappe structures for understanding the closure of the eastern Mongol–Okhotsk Ocean. Meso‐micro structures in the Mohe Formation indicate a low‐temperature deformation/metamorphism (ca. 400°C) under an N‐S compression related to the southward thrusting faulting. The S‐L‐tectonites record strain similar or close to flattening/compressional strain and denote sinistral shearing in analogously N‐S‐trending thrusting. Our new detrital zircon U–Pb ages exhibit that maximum depositional ages of the Mohe Formation were conservatively estimated as latest Middle Jurassic (ca. 165 Ma). The Northeast China and Erguna Block to the south of the Mohe Basin, and Siberian Block to the north were the sources for the Mohe foreland basin's sediments throughout the deposition of the Mohe Formation, which derived from the basement uplift where erosion cuts deep into the dissected arcs. In the latest Jurassic to earliest Cretaceous, the southward collision and indentation of the Siberian Block (final closure of Mongol–Okhotsk Ocean) led to intense thrust nappe structures, syn‐collisional folds, and low‐temperature metamorphism occurred along the northwestern margin of Mohe Basin.

Deformation of granitic rocks within Derbugan Fault belt, Erguna Massif, Northeast China: Implication of the subduction of Mongol‐Okhotsk oceanic plate

“…On the basis of these geochronological and paleomagnetic studies, final closure of the Mongol‐Okhotsk Ocean closed rapidly during the Late Jurassic‐Early Cretaceous (Cogné et al, ; Enkin, Yang, Chen, & Courtillot, ; Halim et al, ; Kravchinsky, Cogné, et al, ; Kravchinsky, Sorokin, & Courtillot, ; Metelkin et al, ; Pei et al, ; Zhang et al, ). At almost the same time, a series of ENE–WSW‐trending thrusts and folds formed in the Erguna Massif (like in western Mohe Basin; Figure b), and the Late Jurassic strata were strongly uplifted (Chang, Wang, Wang, Zhao, & Liang, ; Guo, Yang, Zyabrev, & Hou, ; He, Li, Mo, & Andrey, ; He, Liu, Guo, Hou, & Dong, ; Huang, Dong, Zhang, Miao, & Zhu, ; Li, He, Mo, & Zheng, ; Liang et al, ; Wu et al, ; ), indicating a migration of the orogenic process and possibly indicating the flat‐slab subduction. Later, a hiatus of sedimentation in Songliao Basin began at ca.…”

“…This belt played an important role in the formation and tectonic evolution of the eastern part of the Eurasian continent and CAOB during the Mesozoic (Li et al, ; Tomurtogoo, Windley, Kröner, Badarch, & Liu, ; Xu, Charvet, et al, ; Zorin, ). As for the subduction of Mongol‐Okhotsk Ocean, the oceanic plate is generally considered to have been subducted northwards beneath the Siberian Craton (Donskaya, Gladkochub, Mazukabzov, & Ivanov, ; Safonova & Santosh, ; Zorin, ), and southwards beneath XMOB or Erguna Massif (Chen, Jahn, Wilde, & Xu, ; Chen, Zhang, Wan, Wu, & Cleven, ; Li, Wang, Wilde, & Tong, ; Liang et al, ; Sun et al, ; Tang et al, ; Tang, Xu, Wang, Zhao, & Wang, ; Wang, Guo, et al, ; Wang, Guo, et al, ; Wang, Tang, Xu, & Wang, ; Wang, Xu, Wang, & Meng, ; Wu, Sun, Jahn, & Wilde, ; Xu, Charvet, et al, ). Its evolution has been constrained to the period from the Devonian to the Cretaceous (Cogné, Kravchinsky, Halim, & Hankard, ; Donskaya et al, ; Kelty, Yin, Dash, Gehrels, & Ribeiro, ; Kravchinsky, Cogné, Harbert, & Kuzmin, ; Kravchinsky, Sorokin, & Courtillot, ; Sorokin, Kudryashov, & Kotov, ; Sun et al, ; Tomurtogoo et al, ; Zorin, ).…”

Macro‐and Microstructural, Textural Fabrics and Deformation Mechanism of Calcite Mylonites from Xar Moron‐Changchun Dextral Shear Zone, Northeast China

“…2a; Wu et al, 2007Wu et al, , 2011Cao et al, 2013;Wilde, 2015;Liu et al, 2017;Zhou et al, 2018). This region also witnessed overprinting by the circum-Pacific tectonic domain in the east and the Mongol-Okhotsk tectonic domain in the northwest during the Mesozoic (Li, 2006;Windley et al, 2007;Wu et al, 2007;Xu Y G et al, 2009;Zhou and Wilde, 2013;Guo et al, 2015;Wilde, 2015;Wilde and Zhou, 2015;Liang et al, 2019).…”

“…After the end of the CAOB formation that resulted in the amalgamation and compression of the NCC, Tarim Craton, SIB and several intervening microcontinents, intra -continental strike-slip faults are the prominent tectonic features of Central-Eastern Asia during the Early Mesozoic (Lamb et al, 1999;Johnson, 2004;Webb and Johnson, 2006;Webb et al, 2010;Zhao et al, 2013Zhao et al, , 2015Zhai et al, 2004;Zhang et al, 2013;Heumann et al, 2014). The strike-slip faults can be ascribed to the consequence of several tectonic events, such as the southward subduction of the Mongol-Okhotsk Ocean (Meng, 2003;Zorin, 1999;Enkin et al, 1992;Cogné et al, 2005;Liang et al, 2019), the northwestern subduction of Paleo-Pacific plate , and the far-field effects of the north-directed continental subduction between the NCC-South China Block (SCB) (Rowley et al, 1997;Liu et al, 2006;Meng and Zhang, 1999;Zhang et al, 2013).…”

Preface: Tectonics of China

“…During the late Palaeozoic–Mesozoic, NE China was surrounded by the Palaeo‐Pacific Ocean to the east, Palaeo‐Asian Ocean to the south, and Mongol–Okhotsk Ocean to the north‐west. To understand the influences of the three ocean systems on the tectonic evolution in the NE China, Liang et al () carried out a detailed study of the Mohe Basin located in northernmost NE China and just next to the Russian border. The detrital zircon U–Pb age dating and thrust fault structures, together with the provenance analyses, suggest that the intense thrust nappe structures, syn‐collisional folds, and low‐temperature metamorphism were related to the final closure of the Mongol–Okhotsk Ocean in the latest Jurassic–earliest Cretaceous.…”