摘要
在薄片鉴定的基础上结合元素地球化学分析,研究武汉市金水闸地区碳酸盐岩岩石学和元素地球化学特征,并探讨其沉积环境。结果表明,①大埔组中主要发育泥晶—亮晶白云岩,黄龙组—下窑组中泥晶颗粒灰岩占主导;②大埔组—下窑组碳酸盐岩中具低Ti、Al和Mn/Sr比值(<3),相对贫Cu、Zn、Ga、Fe、V、Ni、Zr、Th等元素,具有低稀土总量(REE为1.64×10^(-6)~13.58×10^(-6))、总体较平缓的稀土元素配分模式曲线以及不同程度的La、Ce负异常和Eu正异常,反映研究区晚古生界碳酸盐岩样品受陆源物质的影响和后期成岩作用的改造较为有限;③结合Sr/Ba、Sr/Ca、Ce/La、V/Cr、U/Th、V/(V+Ni)等元素比值特征,认为研究区碳酸盐岩沉积水体总体表现为氧化环境,自中二叠世茅口组开始,呈现水体变浅、盐度增大的趋势。
On the basis of thin section identification,combined with elemental geochemical analysis,the petrological and geochemical characteristics of carbonate rocks in Jinshuizha area of Wuhan City were studied,and their depositional environment was discussed.The results show that①The Dapu Formation mainly develops micritic-sparse dolomite,and the Huanglong-Xiayao Formation mainly develops micritic grain limestone.②The carbonate rocks of Dapu-Xiayao Formation have low Ti,Al content and Mn/Sr ratio(<3),and are relatively poor in Cu,Zn,Ga,Fe,V,Ni,Zr,Th and other elements.They have low total rare earth elements(∑REE is 1.64×10^(-6)-13.58×10^(-6)),generally gentle rare earth element distribution pattern curves,and different degrees of La,Ce negative anomalies and Eu positive anomalies,reflecting the late Paleozoic carbonate rock samples in the study area.The influence of terrestrial materials and the transformation of late diagenesis are relatively limited.③Combined with the characteristics of element ratios such as Sr/Ba,Sr/Ca,Ce/La,V/Cr,U/Th,V/(V+Ni),it is considered that the carbonate sedimentary water in the study area is generally an oxidizing environment,since the Middle Permian,the water body has become shallower and the salinity has increased.
作者
翁茂芝
郭盼
吴波
罗华
李琳静
龚志愚
Weng Maozhi;Guo Pan;Wu Bo;Luo Hua;Li Linjing;Gong Zhiyu(Hubei Geological Survey,Wuhan,Hubei 430034)
出处
《资源环境与工程》
2022年第5期539-552,共14页
Resources Environment & Engineering
基金
湖北省地质局科技项目(KJ2021-28)
湖北省地质局矿产地质调查项目(KCDZ2022-14)
中国地质调查局武汉地质调查中心工作项目(2020020)。
关键词
碳酸盐岩
地球化学
沉积环境
晚古生界
金水闸地区
武汉市
carbonate rock
geochemistry
sedimentary environment
late Paleozoic
Jinshuizha area
Wuhan City
