藏南定日上白垩统平行不整合界线及其浮游有孔虫时代约束  

THE DISCONFORMITY IN THE LATE CRETACEOUS STRATA AT TINGRI, SOUTHERN TIBET AND ITS AGE CONSTRAINED BY PLANKTONIC FORAMINIFERA

作　　者：吴聪[1] 史宇坤[1] 胡修棉[1] 

机构地区：[1]南京大学地球科学与工程学院,南京210093

出　　处：《微体古生物学报》2011年第4期381-402,共22页Acta Micropalaeontologica Sinica

基　　金：国家自然科学基金(批准号40772070;40902001);国家重点基础研究发展规划(批准号2006CB701402)项目资助的成果

摘　　要：西藏南部定日地区上白垩统旧堡组与遮普惹山坡组之间为平行不整合接触。本文详细研究了定日地区各拉木、申克扎两条剖面中旧堡组与遮普惹山坡组地层的岩石和古生物学特征,系统描述了其中产出的浮游有孔虫13属34种。对浮游有孔虫的研究表明:各拉木剖面旧堡组属康尼亚克-三冬期沉积,上覆遮普惹山坡组沉积开始于坎潘晚期,推断其间的平行不整合界线处缺失了坎潘期约11Ma的沉积;申克扎剖面旧堡组仅出露三冬期的地层,遮普惹山坡组时代最早可能为坎潘中期,其间的平行不整合界线处至少缺失了坎潘早期的地层。A disconformity was discovered in the late Cretaceous strata between the Jiubao Formation and the overly-ing Zhepure Shanpo Formation in the Tingri area,southern Tibet.In this study,two stratigraphic sections(Gelamu and Shenkeza sections) across the disconformity were measured in detail in the field,and planktonic foraminifera were carefully examined to constrain the age of this disconformity.In total,34 species of 13 genera were identified and des cribed in the present paper.At the Gelamu Section,Dicarinella concavataInterval Zone andD.asymetricaRange Zone were recognized in the upper part of the Jiubao Formation which constrain the age of this formation is older than 84 Ma(late Santonian).The oldest deposition age of the Zhepure Shanpo Formation was constrained at late Campanian(approximately 73 Ma) by the occurrence ofGlobotruncanita elevatain the pelagic marls in the lowermost part of this formation.Therefore,early to late Campanian strata(about 11 Ma) are missing represented by this disconformity at the Gelamu Section.At the Shenkeza Section,theD.asymetricaRange Zone is recognized in the uppermost part of the Jiubao For-mation,indicating an age older than late Santonian(approximately 84 Ma).And the deposition age of the Zhepure Shanpo Formation was younger than middle Campanian as suggested by the occurrence ofGlobotruncana ventricosain

关 键 词：浮游有孔虫 上白垩统 平行不整合 西藏定日 

分 类 号：Q915[天文地球—古生物学与地层学]