裂变径迹对豫西宜阳地区中新生代构造演化过程的约束

Constraints of tectonic evolution of Mesozoic and Cenozoic in Yiyang area of western Henan by fission track

为了研究宜阳地区与鄂尔多斯盆地中新生代构造演化过程的时空关系,对宜阳地区开展了锆石、磷灰石裂变径迹测年分析。结果表明,锆石裂变径迹年龄为185±8 Ma,磷灰石裂变径迹年龄为49±3 Ma^41±3 Ma,结合前人资料,认为宜阳地区中新生代以来共经历了两期较大规模的构造改造,分别是晚三叠世—早侏罗世印支运动和始新世—渐新世喜马拉雅运动对本区的影响。这两期构造运动与鄂尔多斯三叠纪原型盆地萎缩及秦岭造山带快速造山均有很好的等时性,说明宜阳地区与鄂尔多斯盆地自中生代以来具有相似的构造背景。

This paper is analysised by zircon and apatite fission track dating,in order to study the spatiotemporal relationship between the Mesozoic and Cenozoic tectonic evolution in the Yiyang area and the Ordos Basin.The results show,zircon fission track age is 185±8 Ma,Apatite fission track age is 49±3 Ma^41±3 Ma.Combined with previous data,this paper is considered there are two large-scale structural transformations have been experienced in Yiyang area since the Mesozoic and Cenozoic,which are correspond the influence of the Indo-Chinese Movement in Late Triassic-Early Jurassic and the Himalayan Movement in Eocene-Oligocene.The tectonic movements in these two phases have a good isochronism with the shrinkage of the Ordos Triassic prototype basin and the rapid orogeny of the Qinling orogenic belt,and shows that the Yiyang area and the Ordos Basin have similar tectonic backgrounds since the Mesozoic.