Stratigraphy, Depositional Environments, and Coalbed Methane Potential of Pennsylvanian Coals -- Bourbon Arch Region, Eastern Kansas

Kansas Geological Survey
Open-file Report 2003-51

Petroleum Significance

Eastern Kansas is the setting of a growing coalbed gas play in recent years. Although most activity is concentrated in the more gas-rich Cherokee Basin in the southeastern part of the state, northward expansion into the Bourbon Arch and Forest City Basin is gaining momentum. Early expansion is partly controlled by a pre-existing pipeline infrastructure (Newell et al., 2002). Coalbed gas resource assessment may further aid companies and local operators in play development around and beyond this pipeline infrastructure.

Geologic Background

The study area encompasses eight counties of east-central Kansas overlying and flanking the Bourbon Arch -- a low, WNW-ESE-trending structural feature dividing the Forest City Basin from the Cherokee and Arkoma basins (Jewett, 1951). The Bourbon Arch and adjacent basins are bound by early Middle Pennsylvanian (Atokan) orogenic features -- the Nemaha Uplift to the west and the Ouachita foldbelt to the south -- and by the pre-Pennsylvanian Ozark Dome to the east. All three tectonic features may have acted as the source of Desmoinesian sediments in the region (Rascoe and Adler, 1983). According to Golonka et al. (1994), the study area was considered to be near-equatorial and humid, with seasonal variations in rainfall as evident by the semi-vertic pedogenic nature of the paleosols underlying coals


The Middle Pennsylvanian Series (Desmoinesian Stage) of eastern Kansas includes numerous thin (<28 inches or 0.71m) coal seams within both siliciclastic and mixed siliciclastic-carbonate “Kansas-type” cyclothems. Coals range in maturity from high-volatile A to B bituminous within the study area (Jewett et al., 1968; Brady, 1997). Atokan and younger sediments found in the Forest City Basin onlap the northern part of the Bourbon Arch. Desmoinesian sediments become thinner over the arch, but are continuous into the Cherokee Basin where they thicken with paleodepth. Mid-Pennsylvanian sediments rest unconformably on a karsted Mississippian carbonate surface.

Four coals are discussed in this poster: Lexington, Bevier, Croweburg, and Neutral.

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Last updated October 2003