supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA22050103, XDB42020203);the National Key Research & Development Program of China (2016YFC0600408);the Taishan Scholar Program of Shandong (ts201712075);Aoshan Scholar Program of the Pilot National Laboratory for Marine Science and Technology (Qingdao)。
Subduction initiation is fundamental for the plate tectonics theory,which has drawn wide attentions[1-5].Ocean-continent transition[1],emergence of plume head[5],age contrast,e.g.,due to displacement of spreading ridg...