Early Eocene sedimentary recycling in the Kailas area,southwestern Tibet:Implications for the initial India–Asia collision
作者单位：State Key Laboratory of Lithospheric EvolutionInstitute of Geology and GeophysicsChinese Academy of Sciences State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum State Key Laboratory of Mineral Deposits ResearchSchool of Earth Sciences and EngineeringNanjing University Department of Earth SciencesUniversity College London
会议名称：《中国科学院地质与地球物理研究所2015年度（第15届）学术年会》
会议日期：2016年
学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学]
基 金：financially supported by a National Natural Science Foundation of China grant (41202082) the MOST 973 Project (2012CB822001) the Foundation of the State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing (grant no.PRP/open-1309)
关 键 词：India–Asia collision Early Eocene Sedimentary recycling Wedge-top basin Southwestern Tibet
摘 要：Syncollisional sedimentary rocks in the Himalayan orogen record important information about the early history of the India–Asia *** article presents a combined stratigraphic,sedimentologic,micropaleontologic,and provenance data for the Early Eocene clastic strata(Dajin Formation)in the Kailas area,southwestern *** Dajin Formation comprises ungraded and normally graded,matrix-and clast-supported conglomerates,ungraded and cross-stratified sandstones,and massive to poorly laminated *** of the rocks is characterized by subaerial and subaqueous debris flows,waning gravity flows and suspension *** larger benthic foraminifera and the youngest ages of the detrital zircons constrain the depositional age to the earliest Eocene(56–54 Ma).The Dajin Formation contains abundant sandstone and mudstone clasts,indicating significant sedimentary recycling in the source area.U–Pb ages of detrital zircons are mostly clustered at20–54 Ma and have positiveεHf(t)values,suggesting a Gangdese *** of the Dajin Formation are interpreted as having recycled from the forearc strata that were originally derived from the Gangdese magmatic *** immature texture and recycled provenance lead us to propose that deposition of the Dajin Formation was a result of the development of fold-thrusts in the Gangdese *** new results and published data from the coeval strata in the Himalayan orogen indicate that an underfilled foreland basin was initiated soon after the initial India–Asia collision,and the Dajin Formation records the wedge-top depozone of the basin system.