REVISED CONODONT BIOSTRATIGRAPHY OF THE DEVONIAN CARBONIFEROUS BOUNDARY INTERVAL IN SOUTHEAST IOWA

The Devonian-Carboniferous Boundary Global Stratotype Section and Point (GSSP) is currently under revision by the International Commission on Stratigraphy-Subcomissions on Devonian (SDS) and Carboniferous (SCS) Stratigraphy. As part of a broader study of the Devonian-Carboniferous boundary interval in Southeast Iowa in conjunction with the Iowa Geological Survey, we sampled Upper Devonian and Kinderhookian strata from Starr’s Cave Park and Preserve, Crapo Park, and the Stony Hallow, all located near Burlington, Iowa. When combined with legacy samples housed at the University of Iowa Paleontological Repository that were collected in the 1960’s, they provide an improved global chronostratigraphic correlation of Iowa Kinderhookian strata.

Conodont samples from the McCraney, Prospect Hill, and Wassonville formations returned a fairly diverse fauna including several important species of Siphonodellids. In particular, the conodonts recovered allow a zonation for the Kinderhookian strata at Starr’s Cave. The presence of Si. quadruplicata, Si. cooperi, Si. sulcata, Si. obsoleta, and Si. sandbergi limit the position of the Prospect Hill Formation in Starrs Cave Park to the sandbergi Zone. The biostratigraphy from the Starrs Cave section along with future work will provide a step in forming a higher resolution correlation of Kinderhookian strata. Additionally, carbon isotope chemostratigraphy is being integrated into the project to provide additional chronostratigrapic correlation for these strata.