地质学报2026，Vol.100Issue(5)：1605-1626,22.DOI:10.19762/j.cnki.dizhixuebao.2025038
青藏高原东北缘共和盆地中晚中新世气候演化及驱动机制
Paleoclimate change and its driving mechanisms in the Gonghe basin(NE Tibetan Plateau)in the Middle to Late Miocene
摘要
Abstract
The paleoclimate of the northeastern Tibetan Plateau during the Middle to Late Miocene may have been controlled by regional tectonic uplift and global cooling.To investigate the impacts of global climate change and tectonic activity on regional climate,as well as to enhance the understanding of the interactions among Earth's spheres,this study focuses on the Miocene sediments from the Gonghe basin in the northeastern Tibetan Plateau.By integrating existing stratigraphic paleomagnetic age data with comprehensive analyses of branched glycerol dialkyl glycerol tetraethers(brGDGTs),total organic carbon isotopes,total organic carbon content(TOC)and heavy mineral composition,we reconstructed the environmental evolution history of the Gonghe basin during this period.The results show that from 14.5 to 8.7 Ma,the paleotemperature reconstructed by brGDGTs steadily decreased(by about 2.3℃),the total organic carbon isotopes increased from-25.23‰ to-24.88‰,pH value increased from 8.1 to 8.7,and TOC decreased by～0.05%,indicating an intensification of aridification.From 8.7 to 6.8 Ma,the total organic carbon isotope decreased from-24.88‰ to-25.23‰,and the pH decreased from 8.7 to 8.2,indicating that the aridification was alleviated.Compared with the previous period,the cooling rate accelerated(increased from 0.4℃/Ma to 1.7℃/Ma),and the content of unstable heavy minerals increased.It is inferred that during this period,the significant uplift of the Elashan and Qinghai Nan Shan around the Gonghe basin formed a topographic barrier to the southeast monsoon,leading to opposite trends in temperature and humidity within the basin.By integrating the tectonic and climatic records from the northern Tibetan Plateau,we believe that the alleviation of aridification in the study area and regions to its east during 9～7 Ma primarily responded to the orographic rainfall effect caused by tectonic uplift.In contrast,the continued aridification since the Middle Miocene in areas west of the study area,such as the Qaidam and Tarim basins,was controlled by both global cooling and tectonic uplift.关键词
共和盆地/中晚中新世/构造隆升/气候转型Key words
Gonghe basin/Middle to Late Miocene/tectonic uplift/climate transition引用本文复制引用
栾天翔,张波,张进江..青藏高原东北缘共和盆地中晚中新世气候演化及驱动机制[J].地质学报,2026,100(5):1605-1626,22.基金项目
本文为国家自然科学基金重点基金项目(编号42430304)和第二次青藏高原综合科学考察研究项目(编号2019QZKK0703)联合资助的成果. （编号42430304）
