贵州镇宁-紫云地区晚泥盆世硅质岩成因机制研究  

The genetic mechanism of the Late Devonian siliceous rocks in the Zhenning-Ziyun area,Guizhou,China

作　　者：涂灵玲 高军波[1,2] 杨瑞东[1,2] 蒋元 谢兴友[3] 刘灵[4] 李鑫正 TU Lingling;GAO Junbo;YANG Ruidong;JIANG Yuan;XIE Xingyou;LIU Ling;LI Xinzheng(College of Resource and Environment Engineering,Guizhou University,Guiyang Guizhou 550025,China;Key Laboratory of Karst Geological Resources and Environment,Ministry of Education,Guizhou University,Guiyang Guizhou 550025,China;The 103 Geological Brigade,Guizhou Bureau of Geological and Mineral Exploration and Development,Tongren Guizhou 554300,China;The 101 Geological Brigade,Guizhou Bureau of Geological and Mineral Exploration and Development,Kaili Guizhou 556000,China)

机构地区：[1]贵州大学资源与环境工程学院,贵州贵阳550025 [2]贵州大学喀斯特地质资源与环境教育部重点实验室,贵州贵阳550025 [3]贵州省地质矿产勘查开发局103地质大队,贵州铜仁554300 [4]贵州省地质矿产勘查开发局101地质大队,贵州凯里556000

出　　处：《矿物学报》2025年第1期134-145,共12页Acta Mineralogica Sinica

基　　金：贵州省找矿突破战略行动重大协同创新项目(批准号:黔科合战略找矿[2022]ZD004);国家自然科学基金项目(批准号:42163006、U1812402);贵州省沉积矿床科技创新人才团队项目(批准号:黔科合平台人才[2018]5613)。

摘　　要：贵州镇宁-紫云地区晚泥盆世广泛发育了一套深水相硅质岩、硅质岩-灰岩建造。本文以贵州镇宁弄染和紫云那岩两条剖面为研究对象,开展了元素地球化学研究,结果表明,镇宁弄染剖面硅质岩Al_(2)O_(3)、ΣREE、(La/Yb)_N和(La/Ce)_N值相对偏低,δEu呈现正异常,δCe为弱负异常。紫云那岩硅质岩Al_(2)O_(3)、ΣREE、(La/Yb)_N和(La/Ce)_N都相对偏高,δEu表现为正异常,δCe为弱负异常。Fe_(2)O_(3)/TiO_(2)-Al_(2)O_(3)/(Al_(2)O_(3)+Fe_(2)O_(3))和(La/Ce)_N-Al_(2)O_(3)/(Al_(2)O_(3)+Fe_(2)O_(3))图解以及其它稀土元素地球化学特征集中显示硅质岩形成于远洋盆地环境。V/(V+Ni)和Th/U等氧化还原敏感元素指示硅质岩沉积时的水体条件为弱氧化-缺氧状态。Al-Fe-Mn和Al_(2)O_(3)/TiO_(2)-Al/(Al+Fe+Mn)图解等反映硅质岩主要为非热液成因,部分硅质岩沉积成岩过程受到一定程度的热液物质混入。结合研究区地质背景,本文认为研究区硅质岩总体产于水城-紫云-南丹断裂控制裂陷盆地内,沉积水体环境为弱氧化-缺氧。A set of deep-water facies of siliceous rock and siliceous rock-limestone were widely developed in the Late Devonian strata in the Zhenning-Ziyun area of Guizhou Province.In this paper,the element geochemical study has been carried out for samples collected from the Nongran section of Zhenning County and the Nayan section of Ziyun County in Guizhou Province.The results show that siliceous rock samples collected from the Nongran section of Zhenning County have relatively low values of Al_(2)O_(3),ΣREE,(La/Yb)N and(La/Ce)N,and positiveδEu anomalies and weakly negativeδCe anomalies,whereas siliceous rock samples from the Nayan section of Ziyun County have relatively high values of Al_(2)O_(3),ΣREE,(La/Yb)N and(La/Ce)N,and positiveδEu anomalies and weakly negativeδCe anomalies.The diagrams of Fe_(2)O_(3)/TiO_(2)-Al_(2)O_(3)/(Al_(2)O_(3)+Fe_(2)O_(3))and(La/Ce)N-Al_(2)O_(3)/(Al_(2)O_(3)+Fe_(2)O_(3))and the geochemical characteristics of other rare earth elements indicate that the siliceous rocks were formed in the pelagic basin environment.The redox sensitive elemental ratios of V/(V+Ni)and Th/U indicate that the water condition during the siliceous rock deposition is in the weak oxidation-anoxic state.The diagrams of Al-Fe-Mn and Al_(2)O_(3)/TiO_(2)-Al/(Al-Fe-Mn)indicate that the siliceous rocks are mainly non-hydrothermal origin.Only a part of them was influenced by the mixing of hydrothermal materials to a certain degree in the process of sedimentary diagenesis.Combined with the geological background of the study area,the siliceous rocks in the study area are generally produced within the rift basin,controlled by the Shuicheng-Ziyun-Nandan fault,in the weakly oxidized-anoxic water environment.

关 键 词：硅质岩 沉积环境 成因 晚泥盆世 镇宁-紫云 

分 类 号：P588.2[天文地球—岩石学] P595[天文地球—地质学]