A Petrologic and Geochemical Study of Authigenic/Diagenetic Clay Minerals in Upper Mississippian Platform-Tidal Flat Carbonate Rocks

文献综述表明，与页岩和砂岩相比，碳酸盐岩中自生和成岩黏土矿物的显微岩石学研究（SEM-EDX，电子探针）相对较少。该项目是对上密西西比陆架潮滩碳酸盐岩的微观岩石学研究，这些碳酸盐岩出现在坎伯兰高原（TN）边缘的良好暴露中。这些岩石含有多种可能的自生/成岩粘土矿物（Ch/S、Ch/V、铜长石、蛭石、伊利石、I/S）。初步SEM-EDX研究（图1-3）证实方解石鲕粒内部存在自生/成岩I/S（4:1）。以上密西西比系碳酸盐岩为研究对象，建立镁质粘土和钾质粘土与方解石、白云石及各种浅层碳酸盐岩环境的成因关系。除了化学、矿物学和岩石学数据外，还将获得空间和体积数据，以便对Mg和其他离子进行质量平衡计算。除了获得粘土矿物的来源信息外，我们还将获得影响镁在硅酸盐和碳酸盐矿物之间分配的因素的信息。本研究的目的是确定碳酸盐岩中粘土矿物反应的性质和意义，揭示成岩作用过程。

A survey of the literature indicates that, compared to shales and sandstones, relatively little micropetrographic work (SEM-EDX, electron probe) has been done on authigenic and diagenetic clay minerals in carbonate rocks. This project is a micropetrographic investigation of the Upper Mississippian shelf-tidal flat carbonates, which occur in excellent exposures along the edge of the Cumberland Plateau (TN). These rocks contain a wide variety of possible authigenic/diagenetic clay minerals (Ch/S, Ch/V, corrensite, vermiculite, illite, I/S). A preliminary SEM-EDX study (Fig. 1-3) confirms the presence of authigenic/diagenetic I/S (4:1) in the interior of calcite oolites. The study will concentrate on the Upper Mississippian carbonates and establish the genetic relation of the Mg clays and K clays to calcite, dolomite and the various shallow carbonate environments. In addition to chemical, mineralogical, and petro- graphic data will be obtained on spatial and volume data so that mass balance calculations can be made for Mg and other ions. In addition to obtaining information of the origin of the clay minerals, we will obtain information on the factors effecting the partitioning of Mg between silicate and carbonate minerals. The goal of this research is to determine the nature, significance of clay mineral reactions in carbonate rocks, shedding light on diagenetic processes.