PRELIMINARY MINERALOGICAL INVESTIGATIONS OF THE BREATHITT GROUP SANDSTONES OF EASTERN KENTUCKY: IMPLICATIONS FOR PROVENANCE AND RESOURCE STUDIES

Few mineralogical details are known regarding the nature of the Breathitt group sandstones of eastern Kentucky. Whether or not these sandstones can be linked to specific source areas in the Appalachians and if these sandstone have any economic interest beyond hosting coal deposits is unclear. This investigation used microscopic techniques to provide basic constraints on the mineralogical diversity of these sandstones to assess if key minerals exist that may be useful for provenance studies and also to determine if there are indicator minerals or minerals of economic interest present. Polarized light microscopy indicates that in addition to detrital quartz, potassium feldspar and plagioclase, muscovite is a common grain mineral in the sandstones with chemical compositions characterized by minor amounts of titanium and sodium, consistent with muscovites of metamorphic origin. Biotite is less common than muscovite and is chloritized to some extent. Cements are dominantly clay minerals and iron oxides. Scanning electron microscopy indicates that these clay minerals are commonly illite and kaolinite. Siderite nodules are common reworked components of sandstones and usually have an oxidized rim. Plant fossil material is also common.

The muscovite compositions are broadly consistent with those from kyanite quartzites in central Virginia, having distinctive Na and Ti compositions. This relationship combined with previous reports of kyanite from limited studies in the area suggest central Virginia may be a source contributor to the sandstones. Sandstone rich in siderite in the region may be a potential reactive media for phosphate sequestration owing to the iron content. Potential also exists for other resource uses.