论文部分内容阅读
浙江浦江县蒙山剖面陈塘坞组凝灰岩样品高精度SHRIMP锆石U-Pb年龄分别为825.3Ma±8.1Ma和830Ma±6Ma,结合江绍断裂带以北的赣西地区修水组凝灰岩获得的SHRIMP锆石U-Pb年龄824Ma±5Ma和星子岩群流纹岩中锆石U-Pb年龄825Ma±5Ma,以及庐山筲箕洼组细碧岩的SHRIMP锆石U-Pb年龄840Ma±6 Ma、流纹岩年龄833Ma±4Ma和831Ma±3Ma,将蒙山剖面陈塘坞组和蒙山组明确定位于820Ma之下,双溪坞群之上的地层单元,从传统的平水群体系中独立出来;并将蒙山剖面陈塘坞组之下的蒙山组枕状玄武岩、细碧岩与庐山地区筲箕洼组枕状玄武岩、细碧岩地层序列对比。陈塘坞组年龄的确定对江绍断裂带区域新元古代地层对比和构造演化具有重要意义。
The high-precision SHRIMP zircon U-Pb ages of the tuff samples of the Chentangwu Formation in the Mengshan section of Pujiang County, Zhejiang Province, are 825.3Ma ± 8.1Ma and 830Ma ± 6Ma, respectively, combined with the XiuShui tuff in the western Jiangxi Province The SHRIMP U-Pb zircon ages of 824Ma ± 5Ma and U-Pb zircon ages of 825Ma ± 5Ma in the Xingzi Group rhyolite and SHMIMP zircon U-Pb ages of 840Ma ± 6 Ma The age of the lithic rocks is 833Ma ± 4Ma and 831Ma ± 3Ma, the Tangtangwu Formation and the Mengshan Formation in the Mengshan section are clearly located under 820Ma, and the stratigraphic units above the Shuangxiwu Formation separate from the traditional Pingshui Group system. The stratiform sequences of pillow-shaped basalt and small bixinite in the Mengshan Formation beneath the Tangtangwu Formation in the Mengshan section are compared with those in the Shau Kewa Formation in the Lushan area. The determination of the age of the Chentangwu Formation is of great significance to the Neoproterozoic stratigraphic contrast and tectonic evolution in the Jiangshao fault zone.