皖浙赣交界莲花山岩体U-Pb锆石年龄及其地质意义

皖浙赣交界莲花山岩体位处扬子板块东南缘，即扬子板块与华夏板块结合带之东段（江南造山带东段北缘）.该岩体侵入于新元古代末期的上墅组（赣东北），岩性主要为正长花岗岩及花斑岩，后期因变质变形作用而发生面理化并具有绿片岩相浅变质矿物组合.地球化学特征指示，莲花山花岗岩很有可能为形成于大陆边缘后造山环境的A₂型花岗岩.锆石LA-ICP-MS U-Pb定年结果显示岩体年龄为878±70 Ma，为晋宁晚期的产物.

U-Pb ZIRCON AGE OF LIANHUASHAN PLUTON IN THE JUNCTION OF ANHUI-ZHEJIANG-JIANGXI PROVINCES: Geological Implication

The Lianhuashan pluton in the junction of Anhui-Zhejiang-Jiangxi provinces is located in the southeast margin of Yangtze Plate, namely the junction zone of Yangtze Plate and Cathaysia Plate (the northern margin of eastern section of Jiangnan orogenic belt). The pluton intruded into the late Neoproterozoic Shangshu Formation (northeastern Jiangxi), with the lithology of syenogranite and granophyres. In later period, the metamorphic deformation resulted in foliated and greenschist facies epimetamorphic mineral assemblage. The geochemical characteristics indicate that the Lianhuashan granite is probably A₂ type formed in continental margin post-orogenic environment. The zircon LA-ICP-MS U-Pb dating of the pluton yields the age of 878±70 Ma, which is the product of late Jinning Period.