中国地质2024，Vol.51Issue(2)：606-622,17.DOI:10.12029/gc20201226001
柴达木盆地北缘新生代沉积物再旋回作用研究:以大红沟剖面为例
Sediment recycling in the northern Qaidam Basin margin during the Cenozoic:A case study from the Dahonggou section
摘要
Abstract
This paper is the result of geological survey engineering. [Objective]Recently,more studies show that the sediment recycling plays an important role in the inversion of the tectonic events,the identification of sediment source areas and the sources of eolian dust.[Methods]In order to explore the Cenozoic sediment recycling in the Qaidam Basin,this paper conducts thin section identification,detrital framework grain composition and heavy mineral analysis of sandstones,and major,trace,and rare earth elements,and clay minerals of mudstones of the Dahonggou section in the northern Qaidam Basin.[Results]The major,trace,and rare earth elements of mudstones are similar to the standard distribution patterns of upper continental crust(UCC)and chondrite,which may indicate that the sediments have been completely mixed or recycled;Sandstone is mainly composed of quartz,and a small amount of feldspar and lithic grains which are mainly composed of sedimentary ones.Sandstone framework detrital mode indicates a provenance type of recycled orogenic belt;The content of stable heavy minerals and ZTR(zircon,tourmaline,and rutile)index suddenly decrease in the upper portion of the section,indicating a closer source area to the section during the late stage;On the contrary,the contents of chlorite,which is easy to decompose,suddenly increase in the upper portion of the section.This observation might also shows that its source area was closer at this time.[Conclusions]Based on the analysis of sedimentary facies,sandstone thin section and detrital zircon U-Pb age,it was suggested that the Jurassic and Cretaceous sedimentary rocks in the thrust-fold belt of the northern Qaidam Basin experienced large-scale sediment recycling and were one of the important provenances of the Cenozoic strata in the basin;Then,the fission-track analyses of detrital apatite show that the Cenozoic sedimentary rocks in the northern margin of the Qaidam basin have experienced significant recycling at 9-7 Ma;After about 3 Ma,with fold-thrusting propagating into the basin center,the uplifted sedimentary rocks in the northern basin experienced recycling,which form the important provenance of the Quaternary lakes within the center of the Qaidam Basin and of the Quaternary loess deposits in China Loess Plateau.关键词
地球化学分析/碎屑颗粒统计/重矿物分析/沉积物再旋回作用/大红沟剖面/沉积盆地/柴达木北缘/地质调查工程Key words
geochemical analysis/detrital framework grain composition/heavy mineral analysis/sediment recycling/Dahonggou section/sedimentary basin/northern Qaidam/geological survey engineering分类
天文与地球科学引用本文复制引用
桑胜萍,卢海建,叶家灿,潘家伟,李海兵..柴达木盆地北缘新生代沉积物再旋回作用研究:以大红沟剖面为例[J].中国地质,2024,51(2):606-622,17.基金项目
第二次青藏高原综合科学考察研究项目(2019QZKK0901)、中国地质调查局项目(DD20190059)、南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0201)联合资助. Supported by Second Tibetan Plateau Comprehensive Scientific Investigation and Research Project(No.2019QZKK0901),the project of China Geological Survey(No.DD20190059),Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(No.GML2019ZD0201). （2019QZKK0901）
