黔中金沙地区早石炭世九架炉组地质特征及沉积环境讨论  

Discussion on the geological features and sedimentary environment of the Early Carboniferous Jiujialu Formation in Jinsha area of central Guizhou

作　　者：周武 韩雪 龙宇 岳龙 徐安全 陈仁 ZHOU Wu;HAN Xue;LONG Yu;YUE Long;XU Anquan;CHEN Ren(Geological Survey of Guizhou Province,Guiyang 550081,Guizhou,China;Guizhou Center of Coal Mine Geological Engineering Consulting and Geological Environment Monitoring,Guiyang 550081,Guizhou,China)

机构地区：[1]贵州省地质调查院,贵州贵阳550081 [2]贵州煤矿地质工程咨询与地质环境监测中心,贵州贵阳550081

出　　处：《华东地质》2024年第2期187-197,共11页East China Geology

基　　金：中国地质调查局“典型沉积岩结构构造图册编制(编号:DD20221645)”;贵州省自然资源厅“毕节试验区金沙县制陶用黏土岩普查(编号:21P0048BH100839)”项目联合资助。

摘　　要：贵州中部地区铝土矿及制陶用黏土岩资源丰富,具有潜在开发优势。文章通过对黔中金沙地区早石炭世大塘期九架炉组的路线详查、剖面测制和矿物鉴定等研究工作,结合指相微量元素分析古环境,研究表明:①.该地层岩石显微结构表现为黏土质铝质岩具显微渗流豆结构、硅质岩呈不等晶结构和铁质岩呈泥晶团粒结构,3个不同显微结构暗示了研究区具有大陆沉积环境特征,岩石类型及岩性组合特征大致反映其整体为还原环境、低能量水动力背景下的陆源碎屑沉积;②.Th/U比值(2.00~7.07)表明该地层黏土岩基本形成于弱氧化环境,Th/U比值随沉积过程逐渐升高反映了氧化作用逐渐加强的过程;③.指示元素B含量((15.3~299.0)×10-6)、Sr含量((14.8~72.9)×10^(-6))、Ba含量((57.0~664)×10^(-6))、B/Ga比值(0.63~6.17)和Sr/Ba比值(0.03~1.11),暗示地层形成早期经历了多次海进—海退过程,并最终过渡为陆相环境。推测金沙地区石炭世大塘期九架炉组位于陆表海地带,因受限于当时古岩溶洼地与隆起的形态、位置及古海水侵入的方向,使得该地层在不同区域表现出复杂沉积特征。There are abundant bauxite and ceramic-making claystone resources with advantageous and developmental potential in the central area of Guizhou Province.Through the research into the route survey,section measurement and mineral identification on Jiujialu Formation in Datang age of GuiZhou Province,in combination with the analysis of paleoenvironment by finger trace element,the findings firstly illustrate that:the microscope observation on this strata of rocks shows vadose pisolith structure of the aluminous clay rocks,isocrystalline structure of the siliceous rocks and micrite-cluster structure of the ferraginous rocks,suggesting a characteristic of continental sedimentary environment in the study area,meanwhile,the rock type and lithology combination characteristics roughly reflect that the whole area is terrigenous clastic deposition under the settings of the reducing environment and low energy hydrodynamic.Secondly,the Th/U ratio indicates that the clay rocks of Jiujialu Formation in the Datang age are basically formed in a weak oxidation environment,and with the rising ratio during the deposition process,the oxidation gradually strengthened at the same time.Lastly,the values of facies element B,Sr and Ba,and the ratios of B/Ga and Sr/Ba indicate that the clay rocks in the Datang age of Jiujialu Formation underwent several transgressions stages and regressions stages in the Early Carboniferous,and eventually turned into a continental environment.It is inferred that Jiujialu Formation in the Datang age of Early Carboniferous in Jinsha area was located in the epicontinental sea zone.As constrained by the shape and position of the palaeokarst and the direction of seawater influx,Jiujialu Formation in Jinsha area appears complex sedimentary characteristics in different areas.

关 键 词：黔中金沙 早石炭世 含铝岩系 九架炉组 沉积环境 

分 类 号：P588.2[天文地球—岩石学]