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。
Aim To discuss arises,development and consumption on structural evolutive course of Ningnan Basin.Methods Using Magnetostratigraphy for Sikouzi development time of the type section.Results Sikouzi development time is 47.1~29.1 Ma B.P.,in Eocene Lutetian to Oligocene Rupelian.Conclusion Ningnan Basin belongs to tensional rift under the extending process before late period Miocene,which has the same structural dynamics environment and similar sedimentary formation character with the same term grabens around.Then Ningnan Basin begins to structure reversal,uplifting,consumption and alteration after the intensifying and expanding of Tibetan structural domain and the rising of Liu-panshan.The geological landform and arc tectonic style with basin and range present after Middle-late Pliocene.