Document Type


Date of Award



Geology, Stratigraphic, Carboniferous, Paleozoic, West Virginia

Degree Name

Doctor of Philosophy (PhD)


Geological Sciences

First Advisor

James R. Beerbower

Second Advisor

Edward Cotter

Third Advisor

Alan C. Donaldson

Subject Heading(s)

Geology--West Virginia--Charleston ; Rocks--Analysis


The late Carboniferous sedimentary rocks in the region north of Charleston, West Virginia consists of cyclothems of deltaic and alluvial origin. The basal part (i.e. the upper part of the Conemaugh Group) includes a) delta front (interbedded sand-dominant and mud-dominant units with thick subunits), b) distributary mouth bar (convex top sandstones and siltstones), c) interdistributary bay (mainly grey mud-clay rocks, and aphanic, highly fossiliferous limestones with abundant Spirorbis, ostracodes), d) levee-splay (silt shale, sandy siltstone with abundant burrows, root structures, and thinly interbedded sand- and mud-dominant units), e) crevasse (sandstone without any vertical decrease in grain size), and f) distributary and meandering channels (thick pebbly sandstones with point bar structures). The Monongahela-Dunkard Group is dominated by alluvial deposits: a) flood-basin (abundant red mud rock with concretionary, pedogenic zones), b) levee-splay (silty shale and interbedded sand- and mud-dominant units, both with abundant carbonate concretions), c) crevasse (single or multiple, thin, stacked, lenticular sandstones) and d) a few meandering channels (pebbly fining upwards type).

Calculation of channel parameters (from epsilon cross-stratification, channel fill width, channel depth and channel perimeter silt and clay percentage) indicate that most of the Carboniferous paleochannel were relatively small and had a mean annual discharge in the range of 1800 to 5100 cfs, though one channel had a mean annual discharge of about 22000 cfs. However, these results should be considered at best an approximation because of questions about applicability of modern stream relations to ancient streams and because of the difficulties of measuring accurately the width and depth values of paleostreams.

The cyclic pattern (determined by Markov chain analysis as well as by visual inspection) typically consists of alternating fining upwards and coarsening upwards hemicycles a pair of which constitute a cyclothem. The cyclothems in Conemaugh seem to be less variable than in the Monongahela-Dunkard although they contain larger number of lithic states in them. The typical fining upward unit in Conemaugh comprises conglomerate – sandstone – siltstone – silt shale – mud-clay rocks – limestone overlain by a coarsening upward sequence of silt shale – sandy siltstone – sandstone. In the Monongahela-Dunkard, the fining upwards hemicycle consists of conglomerate – sandstone – silt shale or mud rock and the coarsening upwards one of interbedded sand-dominant and mud-dominant unit – sandstone.

Evidences suggest that other than a gradual regressive trend, autocyclic factors control the cyclic repeats. Within the deltaic Conemaugh the cyclicity is mainly due to lateral shifting of subdeltaic lobes initiated by crevassing in the levees. The cyclothems within the alluvial Monongahela-Dunkard (where meandering channel deposits are infrequent), is probably due to successive superposition of flood basin muds by levee-splay assemblages and lenticular, single or multiple stacked channels of crevasse origin on flood basin mud. Silting of the crevasse channels completes the cyclothem development.