【摘要】 通过西澳科庭大学离子探针中心的远程测试,在双桥山群横涌组和安乐林组斑脱岩中获得大量锆石,其SHRIMP U-Pb加权平均年龄为831Ma±5Ma(横涌组)、829Ma±5Ma(安乐林组),在河上镇群上墅组中获得加权平均年龄767Ma±5Ma。锆石SHRIMP U-Pb年龄表明华南地区广为发育的双桥山群应归入新元古界,该年龄为标定双桥山群在地层柱中的位置提供了准确的年代学依据。更多还原

【Abstract】 A large number of zircons were obtained from three samples of bentonite in the Hengyong and Anleling formations of the Shuanqishan Group and Heshangzhen Group. They yielded weighted mean 206Pb/238U ages of 831 ± 5 Ma for the Hengyong Forma- tion, 829 ± 5 Ma for the Anleling Formation and 767 ± 5 Ma for the Shangshu Formation of the Heshangzhen Group by the sensitive high-resolution ion microprobe at the SHRIMP center, Curtin University, Western Australia. These ages show that the widespread Shuangqiaoshan and Heshangzhen groups should be assigned to the Neoproterozoic and provide an accurate chronostratigraphic evi- dence for the determination of the location of the Shuanqishan Group in the stratigraphic column.更多还原