SUB-CYCLOTHEM SCALE STRATIGRAPHY OF THE IOLA LIMESTONE (MISSOURIAN/UPPER PENNSYLVANIAN) ALONG THE OUTCROP BELT FROM IOWA TO KANSAS

The application of high-resolution sequence stratigraphy has proven to be very useful in geologic problem solving (such as the characterization of petroleum reservoirs), but the application of these methods generally require access to closely spaced (geographically) cores or outcrop sections. If these data sets are lacking, then the application of these techniques becomes much more problematic. This study represents an attempt to correlate or better understand the sub-cyclothem scale stratigraphy (parasequences) of the Iola Limestone (Missourian, Upper Pennsylvanian) along its outcrop belt from Kansas City, Kansas area to Winterset, Iowa, a distance of approximately 298 km (185 mi).

Previous studies of the Iola Limestone suggest that this stratigraphic interval consists of at least 2 high frequency sequences in Kansas. The temporal and spatial trends in conodont distribution within the Iola support this interpretation. The Iola in the Iowa region seems to have very similar vertical lithofacies stacking patterns, although there are some subtle differences. The Raytown (uppermost) HFS appears to consist of at least two parasequences in the limestone part of the sequence in both Kansas and Iowa, although the way the flooding surface is expressed appears to be different in these two regions. Other studies suggest that the Raytown is a progradational interval, and the possible flooding surface in the Iowa section downlaps to the south into a surface within the Muncie Creek Shale (the transgressive part of the Raytown HFS). If it does not downlap to the south, is it then correlative to the surface in the Raytown in Kansas? If the surfaces are correlative, why would the surface and facies appear to have more significance in the Iowa section that has been interpreted as representing the up-depositional dip direction for this interval?

Sections have been described in both regions and samples were collected for both sedimentological and paleontological information. Samples were processed for conodonts, and the temporal and spatial trends in sections in the two regions will be compared. Temporal and spatial trends in conodont distribution patterns may help clarify the relationship of the Iola in Iowa and Kansas.