摘要
温度低于300℃的低温变质事件的精确测年是一个科学难题,沉积盆地低温变质-流体事件精准测年也是制约沉积盆地热史研究的瓶颈问题。磷酸盐矿物是低温变质沉积岩中的常见自生副矿物,U-Th含量高,具媲美锆石的U-Pb地质计时能力,可用于测定与盆地演化相关的低温变质事件。古老黑色页岩独居石原位U-Pb年代学研究,可精确测定盆地显生宙低温变质-热液事件的期次,进而可恢复沉积盆地构造-热史。本文通过对四川盆地大塘坡组(Nh 2 d)黑色页岩开展独居石原位U-Pb测年,识别出了450Ma、263Ma和246Ma三期低温变质-热液事件,分别与加里东运动、峨眉山地幔柱活动和印支运动有关。这一研究为精确重建克拉通盆地复杂的低温变质期次提供了重要参考。
Precise dating of low-temperature metamorphic events occurring at temperatures below 300℃represents a significant scientific challenge,and accurate dating of low-temperature metamorphic-fluid events in sedimentary basins remains a bottleneck in the study of basin thermal history.Phosphate minerals,commonly found as authigenic accessory minerals in low-temperature metamorphosed sedimentary rocks,exhibit high U-Th contents and possess U-Pb geochronological capabilities comparable to zircon,making them suitable for dating low-temperature metamorphic events associated with basin evolution.In-situ U-Pb geochronological studies of monazite in ancient black shales enable precise determination of the episodes of low-temperature metamorphic-hydrothermal events during the Phanerozoic in sedimentary basins,thereby shedding light on the tectono-thermal history of these basins.This study conducted in-situ U-Pb dating of monazite in black shales from the Datangpo Formation(Nh 2 d)in the Sichuan Basin,identifying three episodes of low-temperature metamorphic-hydrothermal events at 450Ma,263Ma,and 246Ma,respectively.These events are correlated with the Caledonian orogeny,the Emeishan mantle plume activity,and the Indosinian orogeny,respectively.This research provides crucial insights for accurately reconstructing the complex episodes of low-temperature metamorphism in cratonic basins.
作者
王艺壬
刘汇川
訾建威
王丹彤
李文奇
WANG YiRen;LIU HuiChuan;ZI JianWei;WANG DanTong;LI WenQi(Hainan Institute of China University of Petroleum(Beijing),Sanya 572025,China;State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;John de Laeter Centre,Curtin University,Perth,WA 6102,Australia)
出处
《岩石学报》
北大核心
2025年第9期3198-3208,共11页
Acta Petrologica Sinica
基金
国家自然科学基金项目(42472181)
中石油创新基金(2021DQ02-0103)联合资助.
