Opening and Tectonic Evolution of the Paleo-Asian Ocean

Abstract

The Paleo-Asian ocean is defined by units located between the Russian (East European), Siberian, Tarim, and Sino-Korean (North China) continents. The study of the composition, age, and structural position of island-arc magmatic rocks, ophiolites, and high-pressure metamorphic assemblages and their mutual correlations made it possible to identify similarities and differences in the evolution of the Paleo-Asian and Paleo-Pacific oceans. The initial stage of the evolution of the Paleo-Asian ocean defined its opening at 900 Ma, whereas opening of the PaleoPacific took place at 750 to 700 Ma. Closing of the Paleo-Asian ocean in the Carboniferous (NE branch) and the Permian corresponds to the main stage of reorganization and re-opening of the Paleo-Pacific.The maximal opening of the Paleo-Asian ocean occurred after or simultaneously with the first accretion-collision event at 600 to 700 Ma, resulting from the collision of microcontinents and the Siberian continent. Vendian-Early Cambrian boninite-bearing island-arc complexes occur as lavas, sheeted dikes, and sill-dikes associated with gabbro-pyroxenites and ultramafics. These complexes are widely distributed in the Gornyy Altay, East Sayan, and West Mongolian regions and can be considered fragments of a giant boninite-bearing belt.In the late Early Cambrian, collision of seamounts with an island arc caused the squeezing of the subduction zone and return flows within the accretionary wedge. Serpentinite melange within fragments of ophiolites and high-pressure rocks are typical components of the Late Paleozoic accretionary wedges. Because of Middle Cambrian-Early Ordovician collisional events, two new oceans (Junggar-Irtysh-Kazakhstan and Uralian-South Tien Shan-South Mongolian) were formed. The junction of both oceans in East Mongolia opened to the PaleoPacific.

Variable sediment flux in generation of Permian subduction-related mafic intrusions from the Yanbian region, NE China

“…3d), reflecting a late Permian emplacement age for the pluton. In summary, the mafic intrusions from the Yanbian area were formed during 273-254 Ma, when the paleo-Asian Ocean was subducted toward the North China Craton (Dobretsov et al, 1995;Xiao et al, 2003Xiao et al, , 2015Li, 2006;Wilde, 2015).…”

Mesozoic–Tertiary exhumation history of the Altai Mountains, northern Xinjiang, China: New constraints from apatite fission track data

“…Evidence from the Russian section of the Altai Mountains to the west indicate that the mountain belt was progressively denuded throughout the Late Cretaceous and Palaeogene during a period tectonic quiescence (Dobretsov, et al, 1995). Whilst to the east, closure of the Mongol-Okhotsk Ocean in the Jurassic and Early Cretaceous as the SinoKorean continent finally joined with the Siberian Craton, may have led to significant uplift and formation of a large mountain belt.…”

Geochemistry and Nd isotopic composition of the Early Paleozoic flysch sequence in the Chinese Altai, Central Asia: Evidence for a northward-derived mafic source and insight into Nd model ages in accretionary orogen

“…Sengör et al, 1993;Windley et al, 2002;Jahn, 2004;Badarch et al, 2002;Khain et al, 2003;Dobretsov et al, 2004;Hong et al, 2004;Kuzmichev et al, 2005;Helo et al, 2006). Different terranes with various ages accreted into this orogen from c. 1.0 Ga to c. 250 Ma during the evolution of the Palaeo-Asian ocean (Dobretsov et al, 1995a(Dobretsov et al, , 1995bSengör and Natal'in, 1996;Jahn et al, 2000;Khain et al, 2003;Xiao et al, 2003;Windley et al, 2007;Xiao et al, 2009Xiao et al, , 2010. The Altai orogen is one of the major orogenic belts in the central CAOB and situated between the Sayan orogen to the north and the Junggar basin to the south, extending from Russia and East Kazakhstan, through Northern Xinjiang of China, to southwestern and southern Mongolia ( Fig.…”