Late Triassic porphyritic intrusions and associated volcanic rocks from the Shangri-La region, Yidun terrane, Eastern Tibetan Plateau: Adakitic magmatism and porphyry copper mineralization

► The Late Triassic Shangri-La intrusions and associated volcanic rocks in the Yidun terrane have adakitic affinities. ► Flat subduction led to partial melting of oceanic slab, forming early stage high silica adakitic rocks. ► Slab break-off led to extensive interaction between slab melts and mantle, forming late stage low silica adakitic rocks. ► Subducted sediments were involved in the generation of adakitic magma. ► Extensive copper mineralization among the Shangri-La intrusions was closely related to their adakitic affinities.