Granite Petrogenesis And Evolutionary Of Landform In Fugai Mountain, Zhejiang

The granite Fugai granite rock body is situated at the southwest of Zhejiang province and north of Wuyi mountain.In this paper,based on field survey,the emplacement timing,petrogenesis,and possible associated geodynamic setting were discussed by thin section identification,LA-ICPMS,whole-rock major and trace elements and electron microprobe analyzer,and the geomorphological features were analyzed from the perspectives of macroscopic,hit view and microcosmic,the landform evolution process of the whole area was explained.This research not only added the contents of scientific research for Fugai mountain national geological park,but also added the new research data for ZhejiangFujian granite along the southeast coast.In the study area,the host rock is biotite medium-grain monzonitic granite.Zircons from milled samples were selected,U-Pb isotope of zircons from Fugai granite are determined by LA-ICPMS,and yielded a zircon U-Pb age of 103.3±2.7 Ma,implying its end of early Cretaceouscry stallization time.According to petrologic and lithogeochemical characteristics,the granite with weakly negative Eu anomalies is Si-rich,high-alkali,low-phosphorus,enriched in Rb?Th?U,depleted in Ba?Sr?Ti?P and son on,the LREE is slightly more than HREE,and zircon saturation temperatures are 761-791?;on the geochemical characteristics of single minerals,biotites are rich in Fe and poor in Mg,most plagioclases are albite and oligoclase,reflects sodium metasomatism,which indicated that the granite is high fractionated I-type granite.It existed the characteristics of high-K calc-alkaline series and post-collisional granite.Fugai mountain granite has the similar structural environment with the contemporary A and I type granite from Zhejiang-Fujian,and related to the extensional movement after the paleo-Pacific plate colliding the South China plate.This study has played a compensatory role on Fujian-Zhejiang granite band,and it can afford some indication to tectonic kinetics of South China.The granite landscapes of Fugai mountain have their speciality,and the high-altitude falling accumulation is developed and the stone eggs are widely distributed.The crust in Fugai mountain area was stable before Middle Miocene,it was lifted after weathering and denuding,and the stable crust was formed again till Middle Pliocene,and it was strongly lifted again after late pliocene.The recent landform was formed under the joint action of a large number of fractures,strongly weathering,and miarolitic structure after the granite exposing the earth surface.