REVISED CONODONT BIOSTRATIGRAPHY OF THE KINDERHOOKIAN (LOWER TOURNAISIAN) STRATA 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. The tri-state region of Iowa, Illinois and Missouri contains some of the historically most important strata for this interval including the type area of the lowest Carboniferous North American Kinderhookian Stage of the Mississippian Subsystem. Unfortunately, high-resolution conodont biostratigraphy is largely unavailable due to either a lack of study or low resolution sampling by previous investigators that published biostratigraphic research on these strata, much of which was carried out more than 50 years ago.

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 and Crapo Park, both located near Burlington, Iowa, and two other nearby outcrops. Conodont samples were taken from the Famennian “English River”, and the Tournaisian McCraney, Prospect Hill, and Wassonville formations. Samples from the latter three units yield a reasonably diverse conodont fauna, mostly conodonts belonging to the genus Siphonodella. 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.