Discussion On Genesis Of A-type Granite In Southern Luzong Basin, Anhui Province

The A-type granites in the Middle-lower Yangtze river area have close relationship with uranium(gold)deposits,but the origin of the A-type granites is still under debated.More research of these A-type granites in the Middle-lower Yangtze river area can enhance the genetic relationship with uranium(gold)deposit,and provide the beneficial information regarding to the prospect direction.In this workthree typical A-type granites including Chengshan,Hejiaao and Meilin intrusions are systematically studied.Combing with the previous results,comprehensive regional geological survey and geochemical analysis have been carried out to reveal the deeper insight with respect to the origin and evolution processes of these A-type granites.We argue that the formation ages of Chengshan,Hejiaao and Meilin intrusions is around 127 Ma,which represent the latest magmatic event in the Lu-Zong volcanic basin.These granites belong to A-type granites and they were from the same sources.The original source is dominantly composed of meta-sedimentary rocks from Dongling Group,mixed with some mantle material.Fractional crystallization dominates the forming process of these intrusions,predominating by plagioclase and potassic feldspar.