The Cheng’an intrusion in southern Anhui Province is located at the Jiangnan uplift belt, eastern Yangtze plate, is one of the most important intrusive bodies of Yanshanian magmatism. The result of 1∶50 000 regional geological surveying of the Cheng’an sheet shows that the Cheng’an rock mass is a composite one consisted of granodiorite, adamellite and orthoclase granites. It constitutes an independent complex rock mass with complex rock types in southern Anhui, it is a “window” to explore the formation process of Mesozoic granites in this area, and the predecessors research degree of the rock mass is lower. This paper can provide chronological and mineralogical constraints and physical evidence for further discussion on magmatic material sources of Mesozoic granites in southern Anhui. Use the method of zircon U-Pb chronology （LA-ICP-MS） and scanned microscope （SEM）, precise measured the zircon core age and diagenetic age of granodiorite which is the major lithology of the intrusion. Discuss the temperature-pressure conditions of magma formation and petrogenesis by analyzing the contents of potash feldspar, plagioclase and biotite in rock. The results showed that the zircon core age of the granodiorite can be individed into two groups：818～740 Ma and 222～204 Ma, which belongs to Tonian-Cryogenian of new Proterozoic and Mesozoic Late Triassic, the former corresponds the breakup of the Rodinia supercontinent in Precambrian, and the latter is expected to be related to the exhumation of the Dabie Mountains. The diagenetic age of the intrusion was dated to be 151.0±2.8 Ma （MSWD = 0.91）, which shows the magma crystallization and cooling in Late Jurassic. The Cheng’an intrusion is Ⅰ-type granite, formation temperature was 680±55 ℃, forming pressure was 0.21～0.30 GPa, and 6.93～9.90 km in depth. The formation mechanism of the Cheng’an intrusion is partially melted of the crustal material.
Wang Yafei Du Jianguo Chen Xiuqi Xu Jinlong Liu Daobin Ge haiying. Zircon U-Pb geochronology and temperature-pressure conditions study of Cheng’an intrusion in southern Anhui area[J]. Chinese Journal of Geology, 2019, 54(2): 529-548.