徐州大北望寒武系徐庄组海绿石成因探讨  

Investigation of the Genesis of Glauconite in the Cambrian Xuzhuang Formation in Dabeiwang,Xuzhou

作　　者：杨天洋 沈玉林[1,2] 张涛[1,2] 李壮福[1,2] 仝根成[1,2] 刘近帮 YANG Tianyang;SHEN Yulin;ZHANG Tao;LI Zhuangfu;TONG Gencheng;LIU Jinbang(School of Resources and Geosciences,China University of Mining and Technology,Xuzhou 221008,China;Key Laboratory of CBM Resource and Reservoir-Formation Process,China Ministry of Education,Xuzhou 221116,China)

机构地区：[1]中国矿业大学资源与地球科学学院,徐州221008 [2]中国矿业大学煤层气资源与成藏过程教育部重点实验室,徐州221116

出　　处：《高校地质学报》2020年第3期276-285,共10页Geological Journal of China Universities

基　　金：国家自然科学基金项目(41872168)资助。

摘　　要：徐州大北望寒武系徐庄组发育不同类型海绿石,为探讨不同类型海绿石的成因,基于海绿石的矿物学、地球化学及沉积环境分析,利用偏光显微镜、X射线衍射及电子探针等方法对各含海绿石岩层及不同类型海绿石进行系统对比研究查明海绿石的指相意义。结果表明,徐庄组发育颗粒状、碎屑假象状和胶团状三种类型海绿石,其中颗粒状海绿石具有中—高含量钾、高含量铁、砂岩中—高含量铝、石灰岩中低含量铝等特征;碎屑假象状海绿石具有变化大的钾、铁、铝,且保持着其母质形态特征;胶团状海绿石具有高钾、高铁、低铝特点。颗粒状海绿石成因符合颗粒绿化理论,砂岩中海绿石易受环境影响;碎屑假象状海绿石成因符合层状晶格理论及假象替代理论,受到交代和溶蚀作用,因受较强的水动力条件影响成分变化较大;胶团状海绿石是凝胶状海绿石通过胶结作用沉淀,形成于稳定环境中。Different types of glauconites were formed in the Cambrian Xuzhuang Formation in Dabeiwang,Xuzhou.To investigate the genesis of different types of glauconite,analysis of different aspects of glauconite was performed including its mineralogy,geochemistry and sedimentary environment.In addition,polarization microscopy,X-ray diffraction and electron microprobe are used to systematically investigate the different types of glauconite-bearing strata and glauconite to find out the indicative meaning for sedimentary facies of the different types of glauconite.The results show that there are three types of glauconite in the Xuzhuang Formation:granular,detrital illusion,and micellar.Granular glauconite shows medium-high content of potassium,high content of iron,medium-high content of aluminium in sandstone and low content of aluminium in limestone.Detrital illusion glauconite shows a large variety of potassium,iron and aluminium,and maintains the morphological characteristics of its substrates.Micellar glauconite is characterised by high potassium,high iron,and low aluminium.The genesis of granular glauconites can be explained by the verdissement theory and the glauconite in sandstone is susceptible to environmental impacts.The genesis of detrital illusion glauconite follows the layer lattice theory and the pesudomorphic replacement theory,and is subjected to metasomatism and dissolution.The composition of detrital illusion glauconite varies greatly due to strong hydrodynamic conditions.Micellar glauconites are gel-like glauconities precipitated by cementation and are formed in a stable environment.

关 键 词：海绿石 成因类型 沉积环境 地质意义 徐庄组 

分 类 号：P619.214[天文地球—矿床学]