柴达木盆地北缘小柴斜2井早、中侏罗世孢粉组合  

EARLY−MIDDLE JURASSIC SPOROPOLLEN ASSEMBLAGES FROM WELL XIAOCHAIXIE 2 AT THE NORTHERN MARGIN OF QAIDAM BASIN

作　　者：贺振建 张存霞 刘俊民 王大华 胡亮 HE Zhenjian;ZHANG Cunxia;LIU Junmin;WANG Dahua;HU Liang(Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying 257015,China)

机构地区：[1]中国石油化工股份有限公司胜利油田分公司勘探开发研究院,东营257015

出　　处：《微体古生物学报(中英文)》2025年第1期42-57,共16页Acta Micropalaeontologica Sinica

基　　金：中国石油化工股份有限公司科技攻关项目(编号:P22065);胜利油田分公司科技攻关项目(编号:YKS2402)的资助。

摘　　要：在小柴斜2井1930~2350 m井段的大煤沟组三段−七段,发现了丰富的孢粉化石,由下而上可以建立4个组合:①Cyathidites-Classopollis-Inaperturopollenites组合,井深2120~2350 m,大煤沟组三段,地质时代为早侏罗世晚期的托阿尔期;②Cyathidites-Deltoidospora-Disaccites组合,井深2060~2120 m,大煤沟组四段−五段,地质时代为中侏罗世早期的阿林期−巴柔期;③Disaccites-Inaperturopollenites-Psophosphaera组合,井深2010~2060 m,大煤沟组六段,地质时代为中侏罗世中期的巴通期;④Disaccites-Classopollis组合,井深1930~2010 m,大煤沟组七段,地质时代为中侏罗世晚期的卡洛夫期。小柴斜2井早−中侏罗世古气候为亚热带−暖温带,干湿变化阶段性明显:早侏罗世晚期气候较干旱,中侏罗世早期气候潮湿,中期有向干旱转化的趋势,晚期气候干旱。基于岩性特征,认为本井大煤沟组三段上部−五段储集层发育,大煤沟组六、七段烃源岩发育。Abundant pollen and spore grains are discovered from the 1930~2350 m section in depth of Well Xiaochaixie 2,northern Qaidam Basin.They are recognized to form four assemblages:①Cyathidites-Classopollis-Inaperturopollenites assemblage,occurring in 2120 m to 2350 m in depth,the third member of the Dameigou Formation,being Toarcina of late Early Jurassic in age;②Cyathidites-Deltoidospora-Disaccites assemblage,occurring in 2060 m to 2120 m in depth,the fourth and fifth members of the Dameigou Formation,with Aalenian to Bajocian of early Middle Jurassic in age;③Disaccites-Inaperturopollenites-Psophosphaera assemblage,occurring in 2010 m to 2060 m in depth,the sixth member of the Dameigou Formation,being Bathonian of middle Middle Jurassic in age;④Disaccites-Classopollis assemblage,occurring in 1930 m to 2010 m in depth,the seventh member of the Dameigou Formation,being Callovian of late Middle Jurassic in age.Based on the spore-pollen assemblages found here,the palaeoclimate of Well Xiaochaixie 2 during the Early−Middle Jurassic is considered subtropical-warm temperate,with obvious fluctuations of dry and wet stages:being dry in the late Early Jurassic,relatively humid in the early Middle Jurassic,keeping humid but turning drought in the middle Middle Jurassic,and dry in the late Middle Jurassic.Lithological characteristics of the studied well show that the upper part of the third to fifth members of the Dameigou Formation are reservoirs and the sixth and seventh members of the Dameigou Formation are hydrocarbon source rocks.

关 键 词：孢粉 早、中侏罗世 小柴斜2井 柴达木盆地 

分 类 号：P534.45[天文地球—古生物学与地层学] P534.4[天文地球—地质学]