BIOSTRATIGRAPHIC EVALUATION OF BENTHIC FORAMINIFERA ACROSS THE MARMATON-PLEASANTON GROUP BOUNDARY IN KANSAS

This study focuses on enhancing the biostratigraphic understanding of benthic foraminifera within the Pennsylvanian aged strata encompassing the Marmaton-Pleasanton Group boundary in Kansas, specifically spanning the Lenapah Limestone through the basal Pleasanton Shale. Additionally, we address the newly identified regional disconformity at the base of the Nuyaka Creek Shale bed, part of the Lost Branch Formation. A total of 52 samples were collected from the Edmonds A1, Fuqua, and PNR #1 drill cores situated in Leavenworth, Elk, and Linn counties in eastern Kansas. Within the Edmonds A1 Core, we observed foraminifera Ammodiscus sp., at 548 feet, just below the Glenpool Limestone. Moving to the Fuqua drill core, we found ostracods sp., bryozoan, and foraminifera fragments of Textularia sp. in the Glenpool Limestone at a depth of 1724 feet. In the PNR #1 drill core, we identified foraminifera species Stacheia pupoides and Nodosaria gaptankensis immediately below the base of the Bourbon Flags, indicating a Middle-Upper Pennsylvanian age. Furthermore, our investigation revealed the presence of ostracoda Healdia simplicissima in the middle part of the Lost Branch Formation, approximately 9 feet above the basal Nuyaka Creek disconformity. These findings contribute to refining the biostratigraphic framework for benthic foraminifera in this region, aiding in a better understanding of the geological history and evolutionary trends in the study area.