南秦岭西乡群孙家河组锆石SHRIMP U-Pb年龄及其构造地质意义

The Sunjiahe Formation of the Xixiang Group, southern Qinling Ranges: SHRIMP zircon U-Pb age and its tectonic implications

摘要: 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年龄和岩石化学、稀土元素、微量元素等方面的研究。获得的锆石年龄为814.8±5.2Ma,属于晚青白口世。该年龄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,并为研究扬子陆块Rodinia超大陆汇聚时限及秦岭造山带的构造演化提供了新证据。

Abstract: The dacitic lavas from the Sunjiahe Formation in the Xixiang Group, southern Qinling Ranges are examined on the basis of lithochemical, REE and Trace element data, and give a SHRIMP zircon U-Pb age of 814.8±5.2 Ma which represents the late Qingbaikouan. This age provides a new evidence for the approaches to the ages of the transitional besement of the Yangtze block in southern Qinling Ranges, and the convergence timing of the supercontinent Rodinia in the Yangtze block and tectonic evolution of the Qinling orogenic zone.