Discorery of the Neoproterozoic Daolinshan A-type granite in Zhejiang and its tectonic implications

Abstract：The Daolinshan granite is intruded into Proterozoic volcanic rocks and sedimentary rocks and has zircon U-Pb ages of 814 and 816 Ma. The granite formed in the late Jinningian Stage. It is alkali feldspar granite composed mainly of alkali feldspar, quartz with small amounts of plagioclase, biotite, and hornblende. Its mean value of oxides and NK/A ratio are close to those of the world's A-type granite, but compared to M-type, S-type and I-type granite, it is rich in silicon and alkalis and poor in calcium and magnesium. The rock is metaluminous to peraluminous and rich in REE and high field strength elements with a high ratio of FeO*/MgO. The granite pluton formed in a post-orogenic environment and is post-orogenic, aluminous A-type granite. It originated in an extensional environment after the end of the collision of the Yangtze block and Cathaysia block. It is the petrological record of the breakup event of the supercontinent South China Rodinia, revealing that the breakup of the supercontinent in the late Jinningian (Qingbaikouan Period) and so suggesting that the Jiangshan-Shaoxing fault belt had stepped into the stage of extensional breakup in the late Jinningian.