沉积学报2024，Vol.42Issue(2)：545-557,13.DOI:10.14027/j.issn.1000-0550.2022.063
青藏高原中东部囊谦盆地始新世气候变化及其驱动机制
Eocene Climate Change and Its Driving Mechanism in the Nangqian Basin of the Central-eastern Qinghai-Tibetan Plateau
摘要
Abstract
[Objective]Since the Paleogene,with the uplift of the Qinghai-Tibetan Plateau and the large-scale thrust and strike-slip of the strata,many inland basins were formed in the northern part of the Qinghai-Tibetan Plateau.Be-cause of their particular location,the evolution of paleoclimate and paleo-vegetation in the basins is very significant for clarifying the climatic evolution in the Paleogene in Eurasia.[Methods]In this study,the evolution history of paleoclimate and paleo-vegetation in the Nangqian Basin in central and eastern Qinghai-Tibetan Plateau(51.8-37.5 Ma)was reconstructed from biomarkers and total organic carbon(TOC).[Results and Conclusions]The evo-lution history of Paleogene climate index in Nangqian Basin is in three stages,each with different changes of sedimen-tary facies.Stage Ⅰ(51.8-46.4 Ma):The sedimentary facies are mainly fluvial and short-term lacustrine,with lower CPI and TOC values and higher Paq values.ACL and nC27/nC31 show an obvious change trend in this period,which may have been affected by the mixing of terrestrial sediments brought by rivers.Most of the main peak carbon was nC22 and nC23;the vegetation type was predominantly woody plants,and the climate was relatively humid.Stage Ⅱ(46.4-42.7 Ma):The Paq value and nC27/nC31 ratio gradually decreased,ACL gradually increased,the carbon num-ber of the main peak gradually changed from low to medium or high,the vegetation gradually changed from woody to herbaceous plants,and the climate gradually became drought alternating with wet conditions.Stage Ⅲ(42.7-37.5 Ma):Paq,nC27/nC31 and ACL changed little,the carbon number of the main peak increased significant-ly,n-alkanes with high carbon numbers increased significantly,and drought conditions increased.TOC also signifi-cantly increased,reflecting increasing total vegetation productivity,which may have been a response to the warm Middle Eocene Climatic Optimum(MECO).In addition,from comparisons with previous reports of climate change in the study area and adjacent basins,it is considered that the climate change in the Nangqian Basin during 51.8-37.5 Ma was mainly affected by global climate change and the retreat of the Tethys Sea.The uplift of the Qinghai-Tibetan Plateau and its higher elevation greatly influenced water vapor in the Nangqian Basin,whereas monsoons have little influence on water vapor.关键词
正构烷烃/古气候/古植被/囊谦盆地/青藏高原Key words
n-alkane/paleoclimate/paleovegetation/Nangqian Basin/Qinghai-Tibetan Plateau分类
天文与地球科学引用本文复制引用
李尚昆,马贺,魏静宜,魏志福,王永莉,汪亘,马雪云,张婷,何薇,玉晓丽,李伦..青藏高原中东部囊谦盆地始新世气候变化及其驱动机制[J].沉积学报,2024,42(2):545-557,13.基金项目
国家自然科学基金项目(41831176,41972030,41902028) （41831176,41972030,41902028）
国家重点研发计划(2017YFA0604803) （2017YFA0604803）
第二次青藏高原科学考察与研究计划项目(2019QZKK0707) （2019QZKK0707）
中国科学院(B类)战略性先导科技专项项目(XDB26020302) National Natural Science Founda-tion of China,No.41831176,41972030,41902028 （B类）
National Key Research and Development Project,No.2017YFA0604803 （）
The Second Tibetan Plateau Scientific Expedition and Research(STEP)Program,No.2019QZKK0707 （STEP）
Chinese Academy of Sciences Strategic Priority Research Program,No.XDB26020302 （）
