【摘要】 运用层序地球化学方法和原理,结合详细的露头层序地层学研究,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(三级层序1、2、3)构成该二级层序的LST和TST,三级层序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(三级层序4中上部和三级层序5、6)则构成该二级层序的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6次三级海平面变化旋回(6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Hercynian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。更多还原

【Abstract】 The sequence of Lower Permian in Xichang Basin has been divided and correlated by using detailed outcrop sequence geochemistry methods. The authors have divided the sequece into one second order sequence,two sequence groups and six third order sequences. The sequence group P1q( including the 1st,2ndand3 rdthird order sequences) constituted LST and TST of the second order,the condensed section developed near the bottom of the 4ththird order sequence corresponds to MFS,and HST was equivalent to the upper part of P1 m which includes the 5th,6thand upper part of the 4ththird order sequences. Development of the sequence was noted as a period of sea-level rising and the ancient land overlapped by the basin sediment. It was revealed by sedimentary succession,pale oxygenation content,strontium content,variations in carbon and oxygen isotopes and TOC that Xichang Basin had undergone sea level fluctuating for six times in Early Permain,resulted in the occurrence of six third order sequences,which can be correlated with that of southern China or even the world scope. The established sequence filling model revealed that global sea-level rising had taken place in Early Hercynian and the basin continued overlapping the ancient land,forming the outline of Xichang Basin.更多还原