藏南及邻区典型晚新生代盆地磁性地层研究现状与时代对比分析  

COMPARATIVE ANALYSIS ON THE MAGNETIC STRATA DEVELOPED IN THE LATE CENOZOIC BASINS IN THE SOUTHERN TIBET PLATEAU AND ITS ADJACENT AREAS

作　　者：何林[1,2] 吴中海[2] 哈广浩 张海军[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院地质力学研究所,北京100081

出　　处：《地质力学学报》2016年第1期135-151,共17页Journal of Geomechanics

基　　金：国家自然科学基金项目(41171009);中国地质调查局项目"青藏高原东南缘重要活动断裂厘定与活动构造体系综合研究"(1212011120163);中国地质科学院地质力学研究所基本科研业务费项目(DZLXJK201202)

摘　　要：在系统梳理扎达盆地、尼泊尔Thakkhola半地堑盆地、吉隆—沃马盆地、乌郁盆地磁性地层研究成果的基础上,对古地磁年代所代表的地质事件进行了对比和分析,认为藏南及邻区各近南北向裂谷盆地自形成以来均发育2次明显的沉积变动事件,第一次为距今10.6~8.1 Ma期间各盆地分别开始接受沉积,第二次为距今3.5~2.0 Ma各湖盆的连续消亡;总结高原的气候变化可以发现,高原在距今约8 Ma及3 Ma左右也有明显的2次气候变化,即沉积事件与气候变化事件在时间上具有近同时性。扎达盆地、吉隆—沃马盆地、达涕盆地三趾马化石的时代都处于距今7.0~6.5 Ma之间,也具有近同时性。结合高原的整体演化,认为其可能在距今10.6~8.1 Ma、3.5~2.0 Ma发生了2期比较强烈的隆升运动。同时,分析指出了青藏高原南部及邻区晚新生代盆地磁性地层研究过程中存在的问题及解决方法,并对今后青藏高原南部及邻区地区晚新生代磁性地层研究提出了建议。The sedimentary strata among the late Cenozoic extensional rift basins with direction south-north or northeast records some important information about the uplift process of the Tibet plateau in southern Tibet and neighboring areas. Magneto stratigraphy is an important method to define the formation and evolution of the late Cenozoic basins. In this paper,we combed and analyzed the magnetic strata research results about the Zhada basin,Thakkhola basin in Nepal,Gyirong-Oma basin and Wuyu basin systematically. In southern Tibet and neighboring areas,we found two distinct sedimentary change events in the south-north basins since they emerged by the comparison and analysis on the geological events represented by the paleomagnetic chronological.The first is that all the basins began to receive deposits between 10. 6 ~ 8. 1Ma; and the second is that the basins began to die between 3. 5 ~ 2Ma continuously. Moreover,the plateau have two obvious climate changes events at about 8Ma and 3Ma respectively by the summary on the climate change. Therefor the sedimentary and climate changes are near simultaneous. Besides,the ages of the Hipparion fossil in the Zhada basin,Gyirong-Oma basin and Datee basin are between 6. 5 ~7Ma,also with nearly simultaneous. We thought that perhaps there were two relative strong uplift stages on the plateau in 10. 6 ~ 8. 1Ma and 3. 5 ~ 2Ma by contacting with the overall evolution of the Tibet plateau. At the same time,we raised some questions exiting in the research about the magnetic strata of the late Cenozoic basins in the southern Tibet plateau neighboring areas and gave solutions.And,we offered some proposals for future research about magnetic stratigraphy in this region.

关 键 词：青藏高原 晚新生代 磁性地层 近南北向断陷盆地 高原隆升 

分 类 号：P542[天文地球—构造地质学]