Paleobotany of the Corinth Coal Bed, Upper Pennsylvanian, Southern Illinois

Abstract

The Corinth Coal bed is a recently recognized stratigraphic unit in the lower part of the Upper Pennsylvanian Patoka Formation of the Illinois Basin, located between the underlying Chapel Coal and overlying Womac Coal in Southern Illinois. The Corinth Coal was deposited in one or more channels in response to a minor glacial cycle; peat accumulation in this setting was sufficient to support commercial mining operations. Corinth peat accumulation was terminated by a minor marine transgression. The palynoflora of the Corinth Coal is heavily dominated by marattialean tree ferns, particularly Punctatisporites minutus, with lesser amounts of Cyclogranisporites orbicularis and Latosporites minutus. The palynoflora of the Corinth Coal bears greater similarity to the underlying Chapel Coal than to the overlying Womac Coal. A macroflora collected from the gray roof shales of the Corinth Coal likely accumulated in brackish water, based on the occurrence of marine invertebrates. Two roof-shale macrofloral collections were made, 11 years apart, in the same surface mine,. The collections are each dominated by pteridosperms, particularly Neuropteris ovata and Macroneuropteris scheuchzeri. Small numbers of marattialean tree-fern remains also were identified, a pattern that is at odds with the palynology of the coal bed and with coal-balls collected from other Missourian-age coals of the U.S.A. Palynology shows definitively that the Corinth Coal lies between the Chapel and Womac coals, and is typical of the early Missourian of the U.S.A. The macroflora is not diverse and its composition is not diagnostic beyond being consistent with a Missourian age.