东秦岭陕西聂家沟剖面二叠纪—三叠纪之交沉积特征及其古环境意义  

Sedimentary characteristics and palaeoenvironmental significance of the Permian-Triassic transition at Niejiagou section of Shaanxi in eastern Qinling

作　　者：李飞洋 张立军[1,2] 李泰然 杨琦琦 牛永斌 宋慧波[1,2] LI Feiyang;ZHANG Lijun;LI Tairan;YANG Qiqi;NIU Yongbin;SONG Huibo(Institute of Resources and Environment,Key Laboratory of Biogenic Trace and Sedimentary Minerals of Henan Province,Henan Polytechnic University,Henan Jiaozuo 454003,China;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region,Henan Jiaozuo 454003,China)

机构地区：[1]河南理工大学资源环境学院,河南省生物遗迹与成矿过程重点实验室,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

出　　处：《古地理学报》2022年第4期649-662,共14页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金项目(编号:41602112);河南省自然科学基金(编号:212300410349);河南省高校基本科研业务费专项(编号:NSFRF200340);河南理工大学创新型科研团队(编号:2022-05)。

摘　　要：东秦岭陕西镇安聂家沟地区二叠纪—三叠纪之交发育一套海相碳酸盐岩沉积序列,较完整地记录了二叠纪末生物大灭绝事件前后浅海碳酸盐岩台地相生物群落演替及环境变化等信息,是研究二叠纪末生物大灭绝事件前后生态环境变化与沉积响应的理想区域。通过碳酸盐岩微相分析方法,对陕西镇安聂家沟剖面二叠系—三叠系界线附近的碳酸盐岩生物组合和微相类型进行了详细分析,共识别出11个微相类型:斑点状凝块石、叠层石灰岩、鲕粒—纹层状叠层石灰岩、有孔虫颗粒灰岩、藻—海百合泥粒灰岩、含有被包壳和被磨蚀骨屑颗粒的粒泥灰岩、鲕粒颗粒灰岩、集合颗粒灰岩、含鲕粒的粒泥灰岩、泥晶灰岩和泥岩。根据碳酸盐岩微相特征及沉积相标志,在二叠系—三叠系界限附近划分出台地边缘、开阔台地和局限台地3种沉积相,其反映了二叠纪—三叠纪之交频繁的沉积相带变更的特点。该剖面碳酸盐岩微相反映的古生态和生物群落演替特征与中国华南同时期其他剖面具有较好的一致性,即二叠纪末生物大灭绝事件之后,早三叠世正常浅水碳酸盐岩台地生物类型和丰度极低,仅含有少量的双壳类、海百合等,灭绝事件界线附近以微生物碳酸盐岩等特殊微生物沉积构造占主导,之后微生物岩等消失,又出现了以双壳类为首的生物碎屑石灰岩。研究结果为了解二叠纪末生物大灭绝事件中生物和环境的协同演化提供了新的材料和认识。The marine carbonate strata of the Permian-Triassic transition were found in the Niejiagou section of Zhen’an,Shaanxi.It records the succession of biota and environmental changes of shallow-marine carbonate platform in the Permian-Triassic transition,and is a perfect area for studying the depositional response and palaeoenvironmental changes before and after the end-Permian mass extinction.Based on the detailed analysis of carbonate microfacies and biology combination in the Permian-Triassic transition of the Neijiagou section,11 microfacies types are identified,including patched agglomerates,stromatolites,oolitic-layered stromatolites,foraminiferal grainstone,algal-crinoid grainstone,wackestone containing coated and eroded bone debris particles,oolitic grainstone,aggregate grainstone,oolitic wackestone,mudstone and micrite.According to the characteristics of carbonate microfacies and sedimentary indicators,marginal shoal facies,open platform facies and restricted platform facies are divided in the Permian-Triassic transition.The microfacies characteristics reflect frequent sedimentary microfacies changes in the Permian-Triassic transition.The biological succession and stratigraphic sequence of the Permian-Triassic transition in the Niejiagou section have good uniformity correlation with other sections in South China.After the end-Permian mass extinction,low biodiversity and biological abundance,e.g.,small bivalves and crinoid,occur in the shallow-marine carbonate platform in the Early Triassic.The special microbial sedimentary structures dominated around the mass extinction event boundary.Afterwards,the microbialites disappeared and the bioclastic limestone reoccupied.This research can provide new understanding for the coevolution of organisms and the environment caused by the end-Permian mass extinction.

关 键 词：碳酸盐岩微相 生物群落演替 沉积环境 二叠纪末生物大灭绝 秦岭 

分 类 号：P531[天文地球—古生物学与地层学]