Jurassic tectonostratigraphic evolution of the Junggar basin, NW China: A record of Mesozoic intraplate deformation in Central Asia

Abstract

Mesozoic basins in northwest China provide important records for investigating relationships between intraplate deformation in Central Asia and tectonic processes at Asian boundaries. The present study, using well, seismic, outcrop, and thermochronology data in the Junggar Basin and neighboring areas, describes the main features of Jurassic strata in the basin, analyzes the Jurassic evolution of the basin and neighboring mountain belts, and discusses possible mechanisms of Jurassic intraplate deformation in Central Asia. During the Early-Middle Jurassic, episodic uplift of surrounding mountain belts kept the Junggar Basin a contractional closed basin, and alluvial fan, fluvial, delta, and lacustrine depositional environments successively developed from surrounding ranges to the central basin. During the Late Jurassic, the western and central parts of the basin were folded and uplifted, and deposition migrated mainly to the eastern basin. During the latest Jurassic-earliest Cretaceous, pre-Cretaceous strata in the eastern and northeastern Junggar Basin were folded and uplifted, and coarse-grained sediments were transported from surrounding uplifts to the central basin. We suggest that Jurassic episodic deformation events in the Junggar Basin and other areas of Central Asia are related to the Qiangtang collision during the Late Triassic-Early Jurassic, the closure of the western Mongol-Okhotsk Ocean at the Early/Middle Jurassic boundary, a collision of a microcontinent in the Pamir with the southern Asian margin during the late Middle Jurassic-early Late Jurassic, the collision of the Kolyma-Omolon Block with Siberia at the end of the Jurassic, and the subsequent closure of the eastern Mongol-Okhotsk Ocean during the latest Jurassic-earliest Cretaceous.

Late Paleozoic Exhumation of the West Junggar Mountains, NW China

“…During the Late Jurassic, the rest of the basin was affected by a major contractional event. No evidence for significant latest Jurassic contractional deformation could be found in the western Junggar Basin (Yang et al, ). The West Junggar Mountains likely experienced several minor uplift events during the Late Jurassic and Late Cretaceous.…”

“…Direct evidence for Mesozoic fault activity within the West Junggar Mountains is scarce. Evidence from seismic profiles in the western Junggar Basin for reverse faulting suggests some activity during the Jurassic, although this is far more pronounced in the northeastern and southern parts of the Junggar basin than in the west (Li, He, et al, ; Yang et al, ). Cenozoic deformation and reactivation of faults in the West Junggar Mountains has been weak compared to that experienced in the Tianshan (Avouac et al, ).…”

Late-Paleozoic emplacement and Meso-Cenozoic reactivation of the southern Kazakhstan granitoid basement

“…Evidence for these reactivation episodes is often documented in the cooling histories of the exhumed basement rocks and in the sediments of the intervening basins, but the extent of these reactivation events is still under discussion (e.g. De Dumitru et al, 2001;Glorie and De Grave, in press;Jolivet et al, 2013a,b;Vandoorne et al, 2011;Yang et al, 2015). Due to the closure of the Paleo-Tethys Ocean, several accretion-collision events took place at the southern Eurasian margin resulting in the creation of the Mesozoic Tien Shan (e.g.…”

“…In the Issyk-Kul Basin, the Mesozoic sedimentary record contains a few hundred meters of Upper Triassic-Jurassic sediments and minor Cretaceous deposits (Cobbold et al, 1994), while in the southern Junggar Basin, the Mesozoic sedimentary pile is thicker and ends with Cretaceous coarse clastic sediments (Allen et al, 1995;Hendrix et al, 1992;Jolivet et al, 2010;Wang et al, 2013;Yang et al, 2015). Unfortunately, in the IBB, the Mesozoic sedimentary record is relatively poorly known, making direct correlation between the Mesozoic exhumation history and the resulting sediment supply not straightforward.…”

“…A lot of studies demonstrate that Mesozoic deformation in the Tien Shan and Altai was periodical (e.g. Dumitru et al, 2001;Glorie et al, 2011bGlorie et al, , 2012bHendrix et al, 1992;Jolivet et al, 2010;Yang et al, 2015). For example, Choulet et al (2013) correlated Mesozoic episodes of strike-slip faulting and coarse-grained detrital sedimentation in the South Junggar Basin with rotational movements between Kazakhstan, Junggar, Tarim and Siberia, which can be seen as effects of the Cimmerian collisions at the southern Eurasian margin.…”