Abstract:

Using recent research results and previously published data of chronology and petrogenesis, the authors have divided the Indosinian granitoid magmatism into three stages in the middle segment of the Qinling orogen. The early stage of the magmatism is attributed to the northward subduction of oceanic slab coupled with the closure of the Mianxian-Lueyang ocean during 248-216 Ma. The middle stage of the magmatism occurred in the period from the collision between the northern margin of the Yangtze Craton and the North Qiling arc complex zone to the collapse of the orogen during 215-200 Ma. The late stage of the magmatism is considered to have resulted from the delamination of the orogenic root in the post-collision period during 200-195 Ma. Therefore, the Indosinian granitoid magmatism perfectly registered the evolutionary processes of the Qinling orogenic belt.

Key words: middle segment of the Qinling orogen, Indosinian, granite, evolution of the orogen