Discovery and Geological Significance of Adakites in the Tuotuo River Region

A suite of Cenozoic intrusive rocks is exposed in the Tuotuo river region in Qinghai-Tibet plateau. According to the rock assem blage and geochemical characteristics, the rocks can be divided in to two sorts of intrusives: quartz-diorite-porphyrite and diorite-porphyrite. The suite is made up of 13 intrusive bodies in an area of 26.85 km². These rocks are high in Al and Sr, and low in heavy REE. The features are identical to those of adakites. However, their formation environment of compression and subduction is different from the ideal adakites. This is noteworthy of further concern. The article primarily discusses petrologicaland geochemical features, formation ages and environment of the Cenozoic adakite-like intrusive rocks, and also their geological significance for regional geology.