The Shiquan River ophiolitic mélange zone in Xizang: The delineation and significance of a new archipelagic are-basin system

The key problem in the geotectonic division of the Qinghai-Xizang Plateau includes the examination of structures, nature, ages and spatio-temporal relations to the Bangong-Nujiang zone. There exists a complete ophiolite zone in the Shiquan River zone, including four ophiolite subzones. These ophiolite subzones are (arranged) to be separated by three parallel island chains, constituting an Early Cretaceous archipelagic (arc)-(basin) (system). The closure processes represent the (island)-(arc) mountain-building processes in the Shiquan River zone. The subduction polarity is directed chiefly to the north, with a late Yanshanian suture zone intermediate (between) the (Gangdise)-(Tengchong) and (Karakorum)-(South) (Qiangtang)-(Zogang) continental masses, all of which were evolved from the (Bangong)-(Nujiang) zone. The transition from the (Bangong)-(Nujiang) zone to the Shiquan River zone (behaved) just like a way of relay race. The findings cited above may be significant to the division of the tectonic (units) of the (Qinghai)-(Xizang) Plateau and the examination of the tectonic evolution of the (Neo)-(Tethys).