Discovery of Caledonian island-arc granodiorite-tonalite in Buqingshan, Qinghai Province

摘要

The granodiorite-tonalite rock occurred in ophiolitic melange was discovered in Buqingshan area, Qinghai Province. Its Rb-Sr isochron age is 578.15±54.4 Ma which belongs to Early Paleozoic. The rock, belonging to calcic-alkaline series, has the features of island-arc granite, which hints that oceanic crust subduction and island-arc Magmatism occurred in this area in early Paleozoic. This discovery os of great significance of recognize the tectonic Framework and evolution of this area fen as far as the Central orogenic Belt