滇东会泽地区下寒武统渔户村组沉积地球化学特征与古环境重建  

Sedimentary Geochemical Characteristics and Paleoenvironmental Reconstruction of the Lower Cambrian Yuhucun Formation in Huize Area,Eastern Yunnan

作　　者：徐凯 马江波 成战刚 方泽鑫 杨永祯 郭岭[1] XU Kai;MA JiangBo;CHENG ZhanGang;FANG ZeXin;YANG YongZhen;GUO Ling(State Key Laboratory of Continental Dynamics/Department of Geology,Northwest University,Xi’an 710069,China;Exploration and Development Research Institute,Xingzichuan Oil Production Plant of Shaanxi Yanchang Petroleum Co.,Ltd.,Yan’an,Shaanxi 717400,China;Changqing Branch,China Petroleum Logging Co.,Ltd.,Xi’an 710069,China)

机构地区：[1]西北大学大陆动力学国家重点实验室/地质学系,西安710069 [2]陕西延长石油股份有限公司杏子川采油厂勘探开发研究所,陕西延安717400 [3]中国石油集团测井有限公司长庆分公司,西安710069

出　　处：《沉积学报》2025年第2期668-682,共15页Acta Sedimentologica Sinica

基　　金：长庆油田重大科技专项项目(ZDZX2021-03);国家自然科学基金项目(42130206,41302076);大陆动力学国家重点实验室团队重点课题(201210128)。

摘　　要：【目的】埃迪卡拉纪—寒武纪过渡期是地球早期生命演化极为重要的时期,多细胞生命的爆发、辐射与该时期古气候、海水氧含量及海洋沉积环境有着密不可分的关系。为了揭示寒武纪早期生命大爆发时期的古气候和古海洋环境,【方法】以记录寒武纪生命大爆发“事发现场”的滇东地区寒武纪地层为研究对象,基于野外典型露头剖面的详细观察和描述,进行岩石学和沉积学特征的研究,结合主量元素、微量元素和稀土元素的测试分析结果,对滇东会泽朱家箐地区渔户村组沉积时期古海洋及古气候古环境进行重建。【结果】U/Th、V/Cr、V(/V+Ni)值指示会泽地区下寒武统渔户村组沉积时期古海洋处于贫氧—缺氧环境,海水还原性总体上为先减弱后增强的过程,这一过程包含了三个减小—增大的次级旋回变化;Sr/Ca、K/Na值指示古海洋盐度经历了三个增大—减小的次级变化旋回;Sr/Cu、SiO_(2)/Al_(2)O_(3)值指示古气候总体为干旱气候环境,但期间发生波动性升温事件,反映了寒武系早期干湿交替的气候特征。【结论】滇东地区渔户村组沉积时期古海洋环境和古气候的重建,对揭示寒武纪纽芬兰世早期全球生物演变与沉积环境协同演化规律具有重要的意义。[Objective]The Precambrian Ediacaran-Cambrian transition period is extremely important for the evolution of early life on Earth.The explosion and radiation of multicellular life are closely related to the paleoclimate,seawater oxygen content and marine sedimentary environment during this period.In order to reveal the paleoclimate and paleomarine environment during the early eruption of life in the Cambrian,and to understand the relationship between the global paleomarine medium conditions and the co-evolution of early life in the early Cambrian,this study considers Cambrian strata in eastern Yunnan province which recorded the scenario of the eruption of life in the Cambrian.[Methods]The petrological and sedimentological characteristics are based on detailed descriptions of typical outcrop sections in the field.The paleo-ocean,paleoclimate and paleoenvironment of the Yuhucun Formation in Zhujiaqing area,Huize,eastern Yunnan province were reconstructed from tests and analysis of major elements,trace elements and rare earth elements.[Results]The Yuhucun Formation in this region was found to be mainly a set of shallow marine carbonate rocks,accompanied by a small amount of clastic rocks and phosphorite.It was formed in the tidal flat facies belt of the carbonate platform,divided between supratidal-intertidal and subtidal microfacies.The U/Th,V/Cr and V/(V+Ni)values indicate that the paleo-ocean was in an oxygen-poor-anoxic environment during the deposition of the lower Cambrian Yuhucun Formation in the Huize area,and the seawater reducibility was generally weakened.The Sr/Ca and K/Na values indicate that the paleo-ocean salinity experienced three secondary increase/decrease cycles.The Sr/Cu and SiO_(2)/Al_(2)O_(3) values indicate that the paleoclimate was generally arid,but fluctuating warming events during the period reflect dry/wet alternation in the early Cambrian.The regional sea-level change and paleoclimate are consistent with the early Cambrian.[Conclusions]This reconstruction of the paleomarine environment an

关 键 词：扬子板块 渔户村组 朱家箐剖面 磷块岩 古环境 

分 类 号：P595[天文地球—地球化学]