为进一步确定浙西江山上墅组火山碎屑岩年龄及沉积物来源,采用LA-ICP-MS技术对该碎眉岩中的锆石开展U-Pb同位素测年并与邻区锆石年龄对比.结果表明,上墅组火山碎屑岩中锆石U-Pb年龄为717～902 Ma,主要集中分布于 902～883 Ma、875～812 Ma、794～775 Ma 三个区间,峰值分别为(892±7)Ma、(846±7)Ma、(784±9)Ma,记录了华南新元古代裂谷盆地扩张、构造-岩浆-热事件,其中(846±7)Ma峰值可能反映了超级地幔柱的上涌,(784±9)Ma峰值指示了裂谷盆地的扩展.上墅组火山碎屑岩物质主要可能来自浙江中部地区.本研究成果可为江山地区沉积物来源分析、构造演化研究和陆块亲缘关系判别提供依据.
Zircon U-Pb Age of the Neoproterozoic Shangshu Formation in Jiangshan of West Zhejiang and Its Geological Implications
To further determine the age and sediment provenance of the Shangshu Formation volcanic clastic rock in the Jiangshan of west Zhejiang,U-Pb isotope dating of zircon in these clastic rocks was conducted using LA-ICP-MS and compared with zircon ages from adjacent areas.The results show that the U-Pb ages of zircons in the Shangshu Formation volcanic clastic rocks range from 717～902 Ma,primarily distributed in three intervals:902～883 Ma,875～812 Ma,and 794～775 Ma,with age peaks at(892±7)Ma,(846±7)Ma,and(784±9)Ma.These age peaks record the expansion of the Neoproterozoic rift basin,tectonic-magmatic-thermal events in South China,with the(846±7)Ma peak potentially reflecting the upwelling of a super mantle plume,and the(784 士9)Ma peak indicating the expansion of the rift basin.The materials of the Shangshu Formation volcanic clastic rocks likely originated mainly from the central Zhejiang region.The findings of this study can provide a ba-sis for sediment provenance analysis,tectonic evolution research,and the determination of the affinity of continen-tal blocks.
Neoproterozoicvolcanic clastic rockzircon U-Pb ageShangshu FormationJiangshan of west Zhe-jiang
万方数据
维普
