四川西昌盆地下二叠统层序地层论述.pdfVIP

四川西昌盆地下二叠统层序地层研究1 单莉莉 1，覃建雄*1，胡思涵 2 （1.成都理工大学地球科学学院，成都，610059； 2. 成都理工大学沉积地质研究院，成都，610059） 摘要：四川西昌盆地下二叠统的地层划分对比争议较大，油气勘探程度低。本文通过详细的 露头层序地层学研究，结合层序地球化学方法和原理，对西昌盆地下二叠统进行了层序划分 和对比，结果表明：西昌盆地下二叠统地层可划分为 1 个二级层序、2 个层序组和 6 个三级 层序；P1q 层序组构成下二叠统二级层序的 LST 和 TST，层序 4 下部发育的（茅口组底部） 凝缩层相当于二级层序的最大海泛面，而 P1m 中上部（包括层序 4 中上部、层序 5、6）则 构成 HST；西昌地区下二叠统层序发育形成过程，总体表现为海平面上升和盆地不断向古 陆超覆；沉积序列、古氧相含量、锶含量、碳氧同位素和 TOC 的变化旋回揭示西昌盆地早 二叠世经历了六次三级海平面变化旋回（六个三级层序），在华南地区乃至全球范围内均可 进行对比；建立的层序充填模式揭示出早 Hessian 早期全球海平面上升，盆地不断向古陆超 覆，奠定了早二叠世西昌海域盆地的轮廓，Roadian 早期海平面上升达到最高位，并沉积一 套整个华南均可对比的眼球状灰岩或页状藻灰岩，Capitanian 晚期全球构造海平面下降，结 束了西昌地区克拉通盆地的演化阶段。 关键词：层序地层；等时地层界面；下二叠统；海平面变化；沉积充填；西昌盆地 Sequence stratigraphy of Lower Permian of Xichang Basin, Sichuan SHAN Lili1, QIN Jianxiong1, HU Sihan2 (1.Collegy of Toursm and Urban-Rural Planning, Chengdu University of Technology, Chengdu 610059, China; 2.Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China) Abstract: Sequence stratigraphy of the Lower Permian in Xichang Basin, Sichuan Abstract: The Stratigraphic Division and Correlation of the Lower Permian from Xichang Basin of Sichuan are Controversial. Guided by principle of sequence stratigraphic geochemistry, and combined with the detailed studying of outcrop, sequence stratigraphy of the Lower Permian in Xichang Basin was researched and contrasted. One second order sequence, two sequences group and six third order sequences was divided. The second order sequence was constituted with LST, TST, MFS (maximum flooding surface), and HST. LST and TST was Equivalent to P1q。MFS is the condensed section which developed near the bottom of the 4th third order sequence. HST was Equivalent to the up