华北盆地南部济源地区和尚沟组凝灰岩锆石U-Pb定年及其地层学意义  

Zircon U-Pb Age and Stratigraphic Significance of Tuff in Heshanggou Formation,Southern North China Basin

作　　者：杨文涛[1,2] 张鸿禹 方特 冯婉莹 彭深远 Yang Wentao;Zhang Hongyu;Fang Te;Feng Wanying;Peng Shenyuan(School of Resource and Environment,Henan Polytechnic University,Jiaozuo 454003,China;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region,Henan Province,Jiaozuo 454003,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]河南理工大学资源环境学院,河南焦作454003 [2]中原经济区煤层(页岩)气河南省协同创新中心,河南焦作454003 [3]成都理工大学沉积地质研究院,四川成都610059

出　　处：《地球科学》2023年第10期3770-3780,共11页Earth Science

基　　金：国家自然科学基金(No.42072123).

摘　　要：为了约束华北盆地自二叠纪-三叠纪大灭绝后生物复苏与气候转变的时限,对济源地区和尚沟组上部新发现的凝灰岩层进行了LA-ICP-MS锆石定年分析.部分凝灰岩锆石颗粒呈短柱状,少量长柱状,无磨圆,阴极发光照片显示明显的环带结构.剔除轻稀土含量较高的颗粒后,选择其中最年轻的一组样品进行年龄加权平均计算,得到凝灰岩层的就位年龄为244.6±2.8 Ma.该定年结果表明和尚沟组的沉积时代跨越了早-中三叠世,至中三叠世安尼期.同时也约束了华北盆地济源地区的陆地生态系统自奥伦尼克期开始复苏,在中三叠世安尼期全面重建,与海洋生态系统的恢复时限一致;古气候由极端温室向中等温室的转变也发生在中三叠世安尼期,与全球在中三叠的降温趋势一致.In order to constrain the timing for biological recovery and climate change after the Permian-Triassic extinction in North China basin,in this contribution it applies zircon LA-ICP-MS dating of the newly discovered tuff layer in the upper part of the Heshanggou Formation in Jiyuan area.Some zircons occur as short cylindrical shape,with a few elongated grains.All zircons were not rounded,and showed obvious oscillatory zoning characteristics under a cathodoluminescence microscope.After removing zircons with enriched LREE,the remaining zircons showed a weighted mean U-Pb age of 244.6±2.8 Ma.The results show that the stratigraphic age of Heshanggou Formation spanned to the Middle Triassic Anisian age.The new age constrains that the terrestrial ecosystem in North China Basin was fully rebuilt during the Anisian after recovered during the Olenekian,which is consistent with the recovery time of marine ecosystem.The paleoclimate transition from extreme greenhouse to medium greenhouse also occurred in the Anisian age,which is consistent with the continuous global cooling trend in the Middle Triassic.

关 键 词：和尚沟组 三叠纪 凝灰岩 生物复苏 古气候 气候变化 地层学 

分 类 号：P534[天文地球—古生物学与地层学]