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2009年陕西省地质志修编项目组,重点对出露于西乡县城东孙家河附近,南秦岭西乡群孙家河组英安质火山熔岩进行了锆石SHRIMP U-Pb同位素年代学和岩石化学、稀土元素、微量元素等方面的研究,获得了新的同位素年龄为814.8±5.2 Ma。认为该岛弧火山系的形成时代为青白口纪晚期,属晋宁期古扬子板块西缘与青康滇古板块汇聚的产物,为研究南秦岭扬子陆块过渡基底的形成时代,提供了有力的佐证。对进一步详细研究扬子陆块Rodinia超大陆汇聚时限及秦岭造山带的构造演化提供了新的时代证据,具有重要的地质构造意义。
In 2009, the project of reworking of geological records in Shaanxi Province focused on zircon SHRIMP U-Pb isotopic geochronology and petrochemistry on the Yingan mass volcanic lava exposed in the vicinity of Sunjiahe, Xixiang County, Xixiang County, South Qinling Mountains, Rare earth elements, trace elements and other aspects of the study, obtained a new isotope age of 814.8 ± 5.2 Ma. It is believed that the formation of volcanic arc in this island arc is the late Qingbaikou Moutain. It belongs to the product of convergence between the western margin of the ancient Yangtze Plate in Jinning Period and the ancient plate of Qingkang, which provides a powerful force in the study of the formation of the transitional basement of the Yangtze Plateau in South Qinling. The evidence. It provides new epoch evidence for further detailed study of the supercontinent time of the Rodinia Yangtze Delta and the tectonic evolution of the Qinling orogenic belt, which has important geological significance.