Geology of the Clay Deposits in the Olive Hill District, Kentucky

Abstract

THE Olive Hill fire clay bed of Crider (1913) is the principal source of the raw material used in the refractory industry of eastern Kentucky. The bed is a discontinuous underclay from 1 to 20 ft above a prominent unconformity which separates Mississippian and Pennsylvanian rocks. Upper Mississippian rocks consist of ten marine limestone and shale units all truncated by the unconformity. Pennsylvanian rocks are chiefly: (a) massive deltaic sandstone ; (b) cut-and.fill deposits of shale, siltstone and s~ndstone which contain several beds of coal and underclay including the Olive Hill fire clay of Crider (1913) ; and (c) dark-gray shale beds.The Olive Hill fire clay of Crider consists of approximately one-third flint clay, twothirds semiflint clay, and minor amounts of plastic clay. The clay mineral content ranges from nearly pure kaolinite to kaolinitic clay containing about 40 percent illite and mixed-layer clay. The kaolinite ranges from highly crystalline to very poorly crystalline " fireclay " kaolinite. The degree of crystallinity of the kaolinite and hardness of the clay vary inversely with the amount of illite and mixed-layer clay present. The nearly pure kaolinite is believed to have formed by removal of silica and alkalies from mixtures of kaolinite, illite and mixed-layer clay by leaching shortly after deposition.An isopach map shows that Crider's Olive Hill fire clay occurs in irregular, lens-shaped deposits. Fossil plant rootstocks with rootlets attached in the clay clearly indicate it supported plant growth. The overlying coal and presence of some organic material in the clay suggest that the Olive Hill fire clay was deposited under a reducing environment in swamps.

Polygenetic History of Paleosols In Middle-Upper Pennsylvanian Cyclothems of the Illinois Basin, U.S.A.: Part II. Integrating Geomorphology, Climate, and Glacioeustasy

“…It has been described from lower through upper Pennsylvanian strata in the Illinois and Appalachian basins (Foose 1944;Waage 1950;Smith and O'Brien 1965;Williams 1960;Williams et al 1968) and is interpreted to form by chemical leaching and alteration of fine-grained sediments in low-lying acid swamps (Patterson and Hosterman 1960;Keller 1968Keller , 1975Keller , 1981Smith and O'Brien 1965). An uppermost Desmoinesian (upper Shelburn Formation) example was encountered in the MAC core, where it occurs as clasts in a breccia (Figs.…”

Kaolinite clayrocks in the Triassic Banks Wall sandstone of the western blue mountains, New South Wales

“…An autochthonous origin was also proposed by Patterson & Hosterman (1960) to account for the development of the oolitic flint clays of Kentucky. These authors considered that the material formed in situ through attack by acid waters on normal fine-grained sediments in a coal swamp environment.…”

“…The matrix is rather dense and, like the oolites and clasts, is composed of well ordered kaolinite. These coarse-grained kaolinite clayrocks have the characteristics of those forming the oolitic phase of the Garie Formation in the southern sector of the Sydney Basin (Loughnan, 1970) and are virtually indistinguishable in composition and texture from the flint clays occurring in the Pennsylvanian of the Olive Hill area, Kentucky (Patterson & Hosterman, 1960).…”