荆州地区晚三叠世—中侏罗世地层及沉积环境

Early Permian conodonts from the southeastern margin of the Tarim Basin and their significance

晚三叠世—中侏罗世沉积地层特征表明，该时期荆州地区为前陆盆地构造环境，形成于秦岭造山带南部前陆地带，沉积特征及上下接触关系表明其为Ⅰ级构造层。上三叠统和中下侏罗统具有相反的粒序特征和不同的建造特征，分属于两个Ⅱ级层序，分别由３个和７个Ⅲ级层序构成。综合研究结果表明，荆州前陆盆地经历了三个演化阶段，即挠曲变形阶段（Ｔ３ｊ）—粘弹性流变阶段（Ｔ３ｗ）—后期前陆盆地演化阶段（Ｊ１－２），不同演化阶段前陆盆地沉降中心及前隆具纵向迁移的特征，同时，沉积盆地规模及拗陷幅度亦显示规律性变化。

The conodont fossils, first collected from the Keziliqiman Formation in Aqike, Luopu County of the southeastern margin of the Tarim Basin, have been studied in this paper. Neostreptognathodus pequopensis and Sweetognathus inornatus are the main elements of conodont fauna in the Keziliqiman Formation. Based on the feature of fossil assemblages,the conodonts discovered in Keziliqiman Formation are referred to the Neostreptognathodus pequopensis Zone of Permian Artinsikian.The formation in Aqike is referred to Early Permian, instead of Late Carboniferous.