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Dept. of Geology, 120 Lindley Hall, The University of Kansas, Lawrence, KS 66045-2124

Abstract: Ichnology and Depositional History of Douglas Group (Upper Pennsylvanian, Virgilian) Outcrops in Southeastern Chautauqua County, Kansas

Ichnofossils are analyzed from outcrops of the Douglas Group sandstones and shales across a 4 mile transect in southeastern Chautauqua County, Kansas.

Abundant ichnofossils are well preserved in four outcrops in the study area. Ichnogenera include: Paleophycus, Protovirgulana, Nereites, Cruziana, Lockeia, Ofivellites, Aulichnites, and Chondrites. An arthropod trail is present in one location.

Ofivellites is present in conjunction with Calamites plant fragments in the upper part of three sections, indicating very shallow water. At the westernmost site, runnel and rill marks are present, along with Aulichnites, in the troughs of flat-topped ripples, again indicating very shallow water.

One site is composed of a dark-grey platy shale that contains a dwarfed fauna including crinoids, gastropods, brachiopods, and bryozoans. Above the dark-grey shale is a sandstone bed containing numerous Paleophycus burrows in positive hyporelief and negative epirelief.

Sedimentary structures from the four sites include: flat-topped ripples, rill and runnel marks, small scale cross-bedding, load structures, and herringbone cross stratification.

Analysis of ichnofossil assemblages (Ichnofacies) and sedimentary structures in three of the sites reveals a depositional environment of shallow, moderate-energy, well-oxygenated water to very shallow, quiet water.

AAPG Search and Discovery Article #90921©1999 AAPG Mid-Continent Section Meeting, Wichita, Kansas