Zircon SHRIMP U-Pb dating of Xiushui and Majianqiao Formations in northwestern Jiangxi Province
Zircon dating of tuff bed in the Xiushui Formation of the Shuangqiaoshan Group has yielded an age of 824 Ma±5 Ma, with MS WD equal to 1.3, and there are three groups of zircon U-Pb ages for the Majianqiao Formation, of which, one is identical with the age of the Xiushui Formation (824Ma±5Ma, MSWD=1.9), and the youngest age is 769Ma±8Ma (MSWD=0.55). In combination with the SHRIMP U-Pb dating of the tuff bed of the Shuangqiaoshan Group in the eastern part of the Jiangnan oregen, the data of the Fanjingshan and Xiajiang groups in the western part and some ages of the Lengjiaxi and Banxi groups, the authors hold that the Shuangqiaoshan Group should belong to Neoproterozoic strata below the Willing Movement. According to the isotopic data, the Majianqiao Formation should be assigned to the sedimentary strata of the Bans stage. These ages are very important for regional strati-graphic correlation of the corresponding period and tectonic evolution. The zircon U-Pb ages mentioned above demonstrate that Neoproterozoic strata were developed around the age of 820 Ma in northwestern Jiangxi Province. The results obtained also influence the stratigraphic subdivision and correlation of the metamorphosed rocks in whole Jiangnan old land and help geologists solve the problem of geological background and ore-forming conditions of the Jiangnan orogen.
国家科技期刊平台
NSTL
万方数据
维普
