A PRELIMINARY INVESTIGATION OF MATERIALS PROPERTIES OF THE MILLBRIG K-BENTONITE FROM SHAKERTOWN KENTUCKY: A PROMISING MATERIAL FOR ANALOG SHALE AND MATERIALS STUDIES

The Middle-Ordovician Millbrig K-Bentonite from the Shakertown, Kentucky locality was investigated for suitability for use as a source for a variety of studies of rectorite (R1 illite-smectite). Although the unit has been extensively studied for stratigraphic and volcanological purposes, there is little work that focuses on numerous potential applied aspects of this unit. The bed is locally thick (~80 cm) at this locality and may serve as a source for high value applications or scientific research material. Potential uses for Millbrig illite-smectite include (1) experimental material as an analog to better understand the chemical and structural behavior of illite-smectite in shale evolution, (2) substrate or reacted material to use as a catalyst and (3) an absorbent material to be used in environmental applications. Using size-fractionized samples of the less than 2, 0.5, and 0.1 micrometers, various types of data were collected to characterize the variability of the illite-smectite. These data included BET surface area determinations, scanning electron microscopy (SEM), transmission electron microscopy (TEM), as well as thermogravimetric analysis (TGA). This particular location has distinct layers, which were analyzed separately for composition and structural differences. The major impurity in the clay fraction was goethite which is more abundant at contacts. TEM data indicate that the goethite commonly forms stellate composite grains with illite-smectite crystals. Other illite-smectite from the center of the unit is reasonably homogenous with minor variation in platy textures and chemical composition. The investigation led to a contribution toward understanding the role of variability in mineralogy and geochemistry of illite-smectite systems; an important component of petroleum systems. Results indicate that illite-smectite from the Millbrig may be suitable for catalytic and absorption experiments.