GEOCHRONOLOGICAL FRAMEWORK AND TECTONIC BACKGROUND OF GRANITES IN SOUTHERN MARGIN (ANHUI AREA) OF THE NORTH CHINA BLOCK
Mopanshan granite is one of the most typically Paleoproterozoic granite which mainly intruded into the Wuhe Group. The zircon U–Pb isotopic ages of Mopanshan granite is 2196±23Ma. Mopanshan K-feldspar granite is A-type granite, it indicates a non-orogenic extensional tectonic setting.
Neoproterozoic diabase distributed sporadically in Huaibei. the diabase intrude into the Upper Sinian Jinshanzhai Group. Representive rock terrain is Guishan diabase terrain(896.6±16Ma), which formed in the intraplate extensional tectonic environment (Wang.et, 2011).
The magmatic activity was strongly developed since Mesozoic period. The intrusive bodies are mainly distributed in Huaiyuan, Bengbu, Fengyang, Wuhe, and Huaibei areas.
The late Jurassic granites are mainly distributed in Jingshan and Tushan, Bengbu. The Jingshan granite was the typical intrusion with the age of 160 Ma. The granite might form in the post-collision extensional tectonic environment, which was related to of the Dabie-Sulu belt.
The Early Cretaceous granites could be divided into two stages, the early stage and the late stage respectively. The early stage was mainly distributed in Bengbu and Huaibei, such as Houmachang granite (130.5±3.8Ma), Qianchang granite (127.1±1.3Ma).The late stage granites are mainly distributed in Bengbu, such as Xijiazhuang granite (115Ma).Further research suggests that the Early Cretaceous granites formed in the extensional tectonic setting, which is related to the craton destruction caused by the subduction of the Izanagi Plate to the Eurasian Plate.