论文部分内容阅读
目的探讨宁南盆地发生、发展与消亡的构造演化历程。方法通过磁性地层学研究标准剖面寺口子组的沉积时代。结果寺口子组年龄为47.1~29.1 MaB.P.,地层时代对应于中始新世鲁帝特期—早渐新世鲁培尔期。结论至中新世晚期以前,宁南盆地具有和周缘其他同期地堑相似的构造动力学环境和沉积地层特征,属于伸展作用下的拉张断陷。之后,随着青藏构造域影响的增强和扩展,六盘山隆升,宁南盆地发生构造反转并抬升消亡遭受改造。上新世中晚期以来,宁南地区的地质地貌逐渐定型并趋向于现今盆山相间的弧形构造格局。
Objective To explore the tectonic evolution of the occurrence, development and demise of Ningnan basin. Methods By means of magnetic stratigraphy, the sedimentary age of the Teikuko Formation of the standard profile was studied. Results The age of the Shikouzi Formation is 47.1-29.1 MaB.P., and the stratigraphic age corresponds to the Middle Erumian Lutter Period-Early Oligocene Rupeier Period. Conclusion Until the late stage of Miocene, the Ningnan Basin has tectonic dynamic environment and sedimentary stratum similar to other graben along the periphery, which belongs to extensional faulting. Later, with the increase and expansion of the influence of the Qinghai-Tibet tectonic domain, the Liupanshan uplift and the structural inversion in the south Ningxia basin rose up and demise and suffered transformation. Since the middle and late Pliocene, the geology and geomorphology of Ningnan area has gradually settled and tends to the arc-shaped tectonic framework of the present basin-mountain facies.