郑州邙山黄土锆石U-Pb年龄谱——晚第四纪黄土物源变化  

Zircon U-Pb Age Spectrum of Zhengzhou Loess:Provenance change of loess in the Late Quaternary

作　　者：何静[1] 鹿化煜[1] 张瀚之[1] 伍江 邵可涵 HE Jing;LU HuaYu;ZHANG HanZhi;WU Jiang;SHAO KeHan(Frontiers Science Center for Critical Earth Material Cycling,School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学地理与海洋科学学院,关键地球物质循环前沿科学中心,南京210023

出　　处：《沉积学报》2025年第2期527-538,共12页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42021001,41920104005,42271001,41901004)。

摘　　要：【目的】中国黄土高原外围东南部、黄河下游的郑州邙山黄土堆积厚度大,沉积速率快,保存着高分辨率的冰期—间冰期气候和环境变化的记录。为研究郑州邙山黄土物源,以及冰期与间冰期时期邙山黄土与古土壤形成过程的差异及机制,【方法】选取末次间冰期以来郑州邙山黄土—古土壤序列的16件样品,共计4202颗碎屑锆石进行颗粒分离、制靶、激光剥蚀、质谱仪测试,再经过铅校正后得到的U-Pb年龄数据。【结果】结果显示,年龄峰值主要有240 Ma、440 Ma、800~1000 Ma、1800~2000 Ma以及2500 Ma,表明邙山黄土物源区主要是青藏高原东北部以及华北陆块。郑州邙山黄土是黄河及其支流将流域内剥蚀物质运输至下游形成的河漫滩与冲积扇再经风力搬运堆积的产物。冰期时,黄河上游青藏高原东北部的物质贡献相对多;间冰期时,来自华北陆块的近源剥蚀物质对邙山黄土贡献量增加约10%。【结论】对末次冰期—间冰期旋回郑州邙山黄土物源变化的研究,有助于加深对中国中部晚更新世区域剥蚀、沉积环境变化以及黄河流域水系演化等过程的理解。[Objective]The Mangshan loess deposits located in central China Plain,along the southeastern Chinese Loess Plateau(CLP),preserve high-resolution records of paleoclimatic and paleoenvironmental variations at glacialinterglacial scale due to their large thickness and rapid accumulation rate.To explore the mechanism of Mangshan loess formation,as well as the difference and mechanism of the formation process between Mangshan loess and paleosol during the glacial and interglacial periods.[Methods]In this study,sixteen samples,including 4202 detrital zircon particles,comprising the steps of particle separation,target preparation,laser ablation,mass spectrometer testing,lead correction and the like,are analyzed for U-Pb dating from the Mangshan loess-paleosol sequence of the last glacial-interglacial cycle.[Results]The results reveal that the main age spectra peaked at 240 Ma,440 Ma,800-1000 Ma,1800-2000 Ma,and 2500 Ma,indicating that the provenances of Mangshan loess were located in the northeastern Qinghai-Tibetan Plateau and North China Craton.During the last glacial period,denudation materials from the upper reaches of the Yellow River in the northeastern Tibetan Plateau increased,and the eroded sediments were carried by fluvial runoff to the lower reaches of the Yellow River,closing to the Mangshan loess deposit site.During the interglacial period,the contribution of the proximal source materials to the Mangshan loess deposits intensified,and the contribution increased by 10%.[Conclusions]Investigation of the provenance of Mangshan loess can help to better understand the Late Quaternary sedimentary environment in central China,the coupling processes between tectonics and climate as well as the Yellow River evolution during the Pleistocene.

关 键 词：邙山黄土 碎屑锆石 U-PB年龄 冰期—间冰期 物源 

分 类 号：P512.2[天文地球—地质学]