上扬子北缘晚二叠世吴家坪期海洋氧化还原环境重建  

Reconstruction of Ocean Redox Environment During the Late Permian Wuchiapingian,Northern Margin of Upper Yangtze

作　　者：雍茹男 孙诗 陈安清[1,2] 侯明才[1,2] 李夔洲 李乾 黄光辉 李雯 解昊 陈洪德[1,2] YONG RuNan;SUN Shi;CHEN AnQing;HOU MingCai;LI KuiZhou;LI Qian;HUANG GuangHui;LI Wen;XIE Hao;CHEN HongDe(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources,Chengdu University of Technology,Chengdu 610059,China;School of Environment and Resource,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China;School of Earth Environment,University of Leeds,Leeds,UK LS29JT)

机构地区：[1]油气藏地质及开发工程全国重点实验室,成都理工大学,成都610059 [2]自然资源部深时地理环境重建与应用重点实验室,成都理工大学,成都610059 [3]西南科技大学环境与资源学院,四川绵阳621010 [4]School of Earth Environment,University of Leeds,Leeds UK LS29JT

出　　处：《沉积学报》2024年第6期2066-2078,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42402120,42272132);成都理工大学优质青年人才培育特支计划(20200-000526-04);成都理工大学珠峰科学研究计划(80000-2024ZF11402)。

摘　　要：【目的】瓜德鲁普末期生物灭绝之后,生物多样性在晚二叠世开始逐步恢复增长,进一步确定晚二叠世浅海氧化还原状态和演化规律,有助于厘清该时期生物复苏与海洋氧化还原变化之间的关系。【方法】选取上扬子北缘具高分辨率时间框架约束的上寺剖面吴家坪阶作为研究对象,开展了沉积学和沉积地球化学研究,重建了晚二叠世吴家坪期海洋氧化还原环境。【结果】碳酸盐岩铈异常指标和碳同位素在吴家坪期均呈现显著变化,其中碳同位素的正偏和负偏分别对应于晚古生代P4冰期的形成与消融。吴家坪早期生物逐渐复苏导致海洋初级生产力提高和光合作用增强,同时凉爽气候利于洋流循环和氧气交换,该时期整体处于贫氧—氧化环境;吴家坪中期开始,随着气候转暖和晚古生代冰期消亡,海洋通风减弱和海平面上升共同驱动最小含氧带的显著扩张,海洋转变为缺氧环境。【结论】研究重建了晚二叠世吴家坪期浅海环境的氧化还原结构,揭示了晚二叠世海洋缺氧与同期气候—构造事件的深层联系。[Objective]Although the end-Guadalupian extinction is not as well known as the end-Permian extinction,it is regarded as a critical event that resulted in considerable biodiversity loss and significant disruptions to ecosystems.Following the End-Guadalupian extinction,global biodiversity was progressively restored during the Late Permian.Despite this recovery,the intricate relationship between biological resurgence during this era and the redox conditions of palaeo-oceans is still not fully understood[.Methods]The Wuchiaping Formation located in the Shangsi section of the northern margin of the Yangtze Block with high-resolution time frame constraints was selected as the research object.Petrological and sedimentary geochemical studies were employed to reconstruct the marine redox environment associated with the Wuchiaping Formation in the Late Permian.By examining the rock composition and geochemical signatures of the rock samples,we established key indicators of redox conditions(Ce*;Ce anomaly).Additionally,we selected several indicators,including Th,Sc,Y/Ho,and Mn/Sr,to assess whether the redox indicator was influenced by non-redox factors.[Results]The collected global carbon isotope from the Wuchiapingian of Late Permian consistently exhibited a significant positive bias in the early Wuchiapingian,followed by a notable negative bias in the middle Wuchiapingian changes,indicating that this carbon cycle disturbance event had a worldwide impact.Moreover,this transformation corresponds to changes in seawater redox conditions,showing a close correlation between carbon cycle disturbance events and alteration in redox environments.Through comparison of the stratigraphic framework,the disturbance was found to align with the waxing and waning of P4 glaciation.Based on the systematic changes in the Ce anomaly curve of carbonate rocks,the evolution of marine redox conditions during the Wuchiapingian of Late Permian can be divided into three stages,reflecting three distinct global shifts in climate and environmental condit

关 键 词：晚二叠世 Ce异常 海洋缺氧 生物复苏 上扬子 

分 类 号：P512.2[天文地球—地质学]