江汉盆地江陵凹陷申科1井古新世孢粉组合及其地质意义

PALEOCENE PALYNOLOGICAL ASSEMBLAGE OF WELL SKD1,JIANGLING DEPRESSION,JIANGHAN BASIN,HVBH POVWCE,CENTRAL CHINA AND THEIR GEOLOGICAL IMPLICATIONS

江汉盆地白垩纪至古近纪陆相沉积地层发育良好。申科1井位于江汉盆地江陵凹陷,为一口连续取心的科探井。为研究江汉盆地白垩纪/古近纪界线及古新世初期气候-环境的变化,利用申科1井岩心资料,对红花套组、渔洋组的孢粉化石展开了分析。化石主要分布于渔洋组上部及红花套组,以裸子植物含量多为特征,被子和蕨类植物含量为其次。自下而上识别出两个化石组合:Deltoidospora-Ephedripites-Ulmoideipites组合、Pterisisporites-Ephedripites-Nanlingpollis组合。组合1和组合2的时代均为古新世,未找到白垩纪/古近纪界线。本文对富含孢粉化石的渔洋组上部岩心进行定量分析,孢粉植被主要为灌木、针叶林类型,总体反映偏干旱的亚热带气候。

The Cretaceous to Paleogene continental sedimentary stratigraphy of the Jianghan Basin is well developed.Well SKD1 is located at the Jiangling Depression,Jianghan Basin,Hubei Province,Central China,which has a continuous core sequence.To study the Cretaceous/Paleogene Boundary and the change of the Early Paleocene climateenvironment withiu the Jianghan Basin,this paper analyzes the sporo-pollen fossils of the Honghuatao Formation and Yuyang Formation in Well skd.The sporo-pollen fossils are mainly distributed from the Upper Part of the Yuyang Formation and Honghuatao Formation,featured with large amount of gymnosperm and secondly the quilt and fern.We recognized two fossil assemblages from bottom to top,they are Deltoidospora-Ephedripites-Ulmoideipites assemblage and Pterisisporites-Ephedripites-Nanlingpollis assemblage.The age of these assemblages is Paleocene.We did not find the Cretaceous/Paleogene Boundary at well SKD1.This paper quantitatively analyzed the Upper Part of the Yuyang Formation,which is rich in sporo-pollen.The palynological character uflect that the vegetation is mainly shrubs and coniferous forests,under a subtropical drought climate condition.