Assembly of central Asia during the middle and late Paleozoic

Abstract

The core of Asia was assembled during the late Paleozoic by numerous collisions between small continental blocks and by accretionary growth along convergent margins. Although the contributions of the major cratons to the overall growth of Asia through time are relatively well understood, the integration of the kinematics, sedimentary environments, and paleogeography of the large number of smaller elements into the picture is in its infancy. The set of paleogeographic maps in this study is a result of superpositioning fixist paleoenvironmental data sets from China and the former Soviet Union on a digital model of tectonic elements. This merger showed only moderate agreement across the common border through time, but fit known plate tectonic boundaries. Structural, paleontological, paleomagnetic, and paleoclimatic data from other sources appear to be less ambiguous indicators than facies correlation in determining the relationship of individual tectonic elements to their neighbors.Prior to final closure in the Permian, the western segment of the Turkestan ocean separated a northern domain composed of Siberia, Baltica, and the Altaids from an east-west elongate group of elements that extended from North China through Tarim and the Tadjik depression westward to the Scythian-Turanian platform. This group shows indications of geographic continuity beginning in the Early Carboniferous. The southern margin of this group of largely continental blocks formed an east-westoriented subduction zone along which the Paleotethys was subducted northward. One or several marginal basins existed between the Hindu Kush and the Kunlun during the Early Carboniferous. During the late Paleozoic, Yili, the North Tian Shan arc, and the volcanic arcs of southern Mongolia, all of which belonged to the Turkestan ocean realm, accreted to the North China-Tarim-Turan assemblage, typically along diachronously closing basins. Diachronous, west to east closure of the Turkestan ocean throughout the late Paleozoic and collision of the Altaids with the eastern European margin contributed to the construction of the nuclear Eurasian landmass.Large-scale kinematic problems in central Asia include, among others, the eastward and westward extent of the Tarim block during Paleozoic time, the timing of closure of the Turkestan ocean, the tectonic framework of the Aral Sea-pre-Caspian region, and the magnitude of Permian strike-slip tectonics.

Late Palaeozoic and Meso-Cenozoic tectonic evolution of the southern Kyrgyz Tien Shan: Constraints from multi-method thermochronology in the Trans-Alai, Turkestan-Alai segment and the southeastern Ferghana Basin

“…The Permian post-collisional plutons across the Tien Shan are related to the final amalgamation stage of the ancestral Tien Shan orogen and of the CAOB as a whole. The ancestral Tien Shan was constructed when frontal collision of the palaeo-Kazakhstan continent with (Karakum)-Tarim occurred (Allen et al, 1992(Allen et al, , 1995Carroll et al, 1995;Gao et al, 1998;Heubeck, 2001;Windley et al, 2007;Xiao et al, 2010). Next to the development of postcollisional igneous complexes, this large-scale orogenic event produced significant relief in the Tien Shan orogen and thick Permian molasse type deposits accumulated in the foreland and intramontane basins (e.g.…”

“…Late-and post-orogenic deformation and magmatism further shaped the CAOB basement architecture and the ancestral Tien Shan in particular (e.g. Allen et al, 1992;Carroll et al, 1995;Gao et al, 1998;Heubeck, 2001;Windley et al, 2007;Xiao et al, 2010). Evidence for widespread Late Carboniferous to Permian strike-slip deformation and shearing and rotation (Allen et al, 1995;Laurent-Charvet et al, 2002;Buslov et al, 2003b), and thus oroclinical bending (Van der Voo et al, 2006) are prevalent throughout the region, as is the presence of contemporaneous post-collisional granitoids (e.g.…”

Middle Cambrian to Permian subduction-related accretionary orogenesis of Northern Xinjiang, NW China: Implications for the tectonic evolution of central Asia

“…8. ing of the Japan-type, Andean-type and in Mariana-type margin processes, in which forearc accretion is the principal mechanism but backarc closure also plays a key role (S ßengör and Natal'in, 1996;Natal'in and S ßengö r, 2005;Xiao et al, 2002aXiao et al, ,b, 2003Xiao et al, , 2004aXiao et al, ,b, 2005. The multiple accretionary processes led to significantly lateral growth of central Asia, shedding light on global reconstruction in the Paleozoic (Heubeck, 2001;Yakubchuk, 2002Yakubchuk, , 2004Torsvik and Cocks, 2004).…”

Structural analysis and 40Ar/39Ar thermochronology of Proterozoic rocks in Sailimu area (NW China): Implication to polyphase tectonics of the North Chinese Tianshan

“…resulted from subduction of oceanic lithosphere of the paleo-Asian Ocean Yarmolyuk et al, 2006) or Turkestan Ocean (e.g. Heubeck, 2001) located between microcontinents (e.g. Central Tianshan, Chu-Yili, Aktau-Junggar from south to north) and island arcs (e.g.…”