Late Mesozoic tectonic evolution and growth of the Tibetan plateau prior to the Indo-Asian collision

Late Cretaceous high-Mg# granitoids in southern Tibet: Implications for the early crustal thickening and tectonic evolution of the Tibetan Plateau?

“…9). Moreover, previous research has indicated that the northern Lhasa subterrane underwent Late Cretaceous northward-directed subduction under the Qiangtang terrane rather than southward subduction beneath the central Lhasa subterrane (e.g., Kapp et al, 2005Kapp et al, , 2007Zhang et al, 2012). Consequently, it is unlikely that the Zhongcang adakitic rocks could have formed as a result of interaction between crustal-derived melts generated from the southward-subducting northern Lhasa subterrane and overlying mantle wedge material.…”

“…Subsequently, the collision of the Lhasa and Qiangtang terranes may led to significant crustal thickening of the Lhasa terrane prior to India-Asia collision (e.g., Murphy et al, 1997;Yin and Harrison, 2000;Kapp et al, 2003Kapp et al, , 2005Kapp et al, , 2007Volkmer et al, 2007;Zhang et al, 2012;Sun et al, 2015a). Responsible for these evolutionary processes, Mesozoic magmatic rocks are widely distributed in the southern Tibet, which can offer important insights into mantle-crust interaction and the growth of the continental crust (e.g., Zhu et al, 2011Zhu et al, , 2013Sui et al, 2013).…”

“…The thickening of a region of the lower crust and its associated lithospheric roots probably led this region to become unstable and undergo delamination at 94-88 Ma, causing an increase in the thermal gradient of the area as well as regional extension and uplift within the central-northern Lhasa terrane (Qu et al, 2006;Xin et al, 2007;Zhang et al, 2012;Wang et al, 2014;Sun et al, 2015b). The high-temperature mantle material that surrounded the delaminated lower crust also caused dehydration melting of the latter, forming partial melts that reacted with the surrounding mantle material during ascent to crustal depths, forming the Zhongcang high-Mg# adakitic rocks within the central Lhasa subterrane.…”

Middle Jurassic MORB-type gabbro, high-Mg diorite, calc-alkaline diorite and granodiorite in the Ando area, central Tibet: Evidence for a slab roll-back of the Bangong-Nujiang Ocean

“…To the south, the Lhasa terrane is divided into northern, central, and southern subterranes, based on basement rocks and sedimentary cover . Differently, to the north of the BNSZ, some researchers recently suggested that the Qiangtang terrane was composed of two subterranes separated by the east-westtrending Longmu-Shuanghu suture (Li et al, 2006;Zhang et al, 2012;Zhu et al, 2013). The Longmu-Shuanghu suture is usually considered as a residue of an Ordovician-Triassic Paleo-Tethyan ocean (Liu et al, 2011;Yin and Harrison, 2000;Zhu et al, 2013).…”

“…Zhang et al, 2014;Zhu et al, 2013). The microcontinent consists mainly of orthogneisses with minor metasedimentary rocks, mafic amphibolites and migmatites, which were intruded by Jurassic granitoids Zhang et al, 2012;Zhu et al, 2011). Beside Nyainqêntanglha massif, the Ando microcontinent is the only one with well defined outcrops of Neoproterozoic (920-820 Ma) and CambrianOrdovician (540-460 Ma) crystalline basement in the interior of Tibet (Guynn et al, 2006;Kapp et al, 2005;Xu et al, 1985;Zhu et al, 2011).…”