Triassic continental subduction in central Tibet and Mediterranean-style closure of the Paleo-Tethys Ocean

Silurian high-pressure granulites from Central Qiangtang, Tibet: Constraints on early Paleozoic collision along the northeastern margin of Gondwana

“…The Carboniferous to Permian rocks of the SQT are characterized by glaciomarine deposits and cold-water biota, which are typical indicators of a Gondwanan affinity (BGMR, 1993;Jin, 2002;Li and Zheng, 1993;Li et al, 1995;Zhang et al, 2009). Detrital zircon ages from Carboniferous sandstone and quartzite in the SQT are similar to those from Carboniferous strata in the Himalayan and Lhasa terranes (Leier et al, 2007;Pullen et al, 2008).…”

Late Triassic high-Mg andesite/dacite suites from northern Hohxil, North Tibet: Geochronology, geochemical characteristics, petrogenetic processes and tectonic implications

“…The Late Permian Emeishan mantle plume on the western margin of the South China Block is considered to have caused the inferred rifting (e.g., Chung and Jahn, 1995;Song et al, 2004). In the second model, the Songpan-Ganzi basin is interpreted as a back-arc basin between the Kunlun arc to the north and the outboard Yidun arc to the south (e.g., Burchfiel et al, 1995;Pullen et al, 2008;Şengör et al, 1988;Watson et al, 1987) (Fig. 1).…”

“…1). Pullen et al (2008) proposed an alternative back-arc basin model where, after middle Triassic collisions between the North China and South China Blocks and between the Qiangtang and Paleo-Tethys arc terranes, collision-induced oceanic slab rollback led to rifting of the eastern Kunlun terrane (Yidun arc) from Eurasia and opening of a back-arc basin in which Songpan-Ganzi flysch was deposited. Late Triassic arc fragments (e.g., Yidun) and the Songpan-Ganzi flysch were then accreted to the Qiangtang terrane and South China Block.…”

“…1a), there are important issues that remain to be resolved, including (1) the relationship between late Permian basaltic magmatism and the mantle plume activity in western South China (Chung and Jahn, 1995;Song et al, 2004;Xiao and Xu, 2005), and (2) the polarity or direction and timing of the different subduction systems (Burchfiel et al, 1995;Nie et al, 1994;Pullen et al, 2008;Reid et al, 2007;Roger et al, 2004;Şengör et al, 1988).…”

“…The tectonic setting of these sedimentary strata has long been disputed. Based on tectonic and sedimentary analyses, the strata were considered to have formed in a variety of tectonic settings such as an intracontinental rift (e.g., Song et al, 2004), a back-arc basin (e.g., Burchfiel et al, 1995;Pullen et al, 2008;Şengör et al, 1988;Watson et al, 1987), a foreland basin (Yuan et al, 2010), and a remnant oceanic basin (e.g., Nie et al, 1994;Weislogel, 2008;Weislogel et al, 2006;Yin and Harrison, 2000;Zhou and Graham, 1996). So far, the majority of HSGB studies have been conducted in the east, where interactions with surrounding blocks (e.g., the South China, Kunlun-Qaidam, North China, South Qinling, Qilian, Yidun, and Qiangtang Blocks; Fig.…”