鄂尔多斯地区南缘寒武纪层序地层和海平面变化  

SEQUENCE STRATIGRAPHY AND SEA LEVEL CHANGE OF THE ORDOVICIAN IN THE SOUTHERN MARGIN OF ORDOS REGION

作　　者：蔡忠贤 秦玉娟 贾振远[1,2] 

机构地区：[1]石油地质系 [2]杭州石油地质研究所

出　　处：《地球科学（中国地质大学学报）》1997年第5期474-490,共17页Earth Science-Journal of China University of Geosciences

基　　金：国家基础性研究重大项目"中国大陆及其边缘层序地层及海平面变化研究"(SSLC)资助

摘　　要：通过对鄂尔多斯盆地南缘河津、歧山及陇县３个下古生界露头剖面的研究、对比表明，华北型的寒武系自辛集组至凤山组可识别出１４个三级层序，这些层序在生物地层上大体可与１～３个标准三叶虫带相对应，年代地层上除下寒武统２个层序形成时间在可能大于５Ｍａ之外，中—上寒武统的层序均在２～３Ｍａ之间．进一步利用盆地沉降分析模型逐步对下古生界累积去压实厚度曲线进行沉积物负载消减、盆地构造热沉降消减后发现，本区的盆地构造沉降曲线（Ｒ１曲线）与麦肯齐的被动边缘指数沉降曲线可完全类比，由绝对海平面及局部构造作用产生的可容空间曲线（Ｒ２曲线）与北美寒武纪的Ｒ２曲线也非常相似，因而更证明了二级可容空间事件是绝对的．The Ordovician in the southern margin of Ordos region can be divided into twelve sequences. Ordos contains an important key time of crust evolution at the Ordovician, so there are apparent changes between the Early Ordovician and the Middle Late Ordovician. The Early Ordovician (Yeli Liangjiashan Epoch, Majiagou Epoch, Fengfeng Epoch) was a passive continental margin that can be divided into seven sequences. The sea level rose abruptly in the Early Ordovician, which then fell gradually. The Middle and Late Ordovician (Zhaolaoyu Epoch, Shangdian Epoch) were an active continental margin. It can be divided into five sequences. The sea level of large scale turned out regression in the Middle and Late Ordovician so that all Ordos region was exposed above sea level. As the sea water abruptly deepened in the southern margin of Ordos region, the sea level subsequently fell, all Ordos region was exposed above sea level in the Late Ordovician.

关 键 词：海平面变化 寒武纪 层序地层 盆地 

分 类 号：P534.41[天文地球—古生物学与地层学] P731.23[天文地球—地质学]