HIGH-RESOLUTION INTEGRATED CONODONT AND CARBONATE CARBON ISOTOPE CHEMOSTRATIGRAPHY OF THE HANGENBERG EXCURSION FROM THE H-28 AND H-32 CORES BURLINGTON, IOWA

The Devonian-Carboniferous (D/C) boundary interval is marked by one of the largest biogeochemical perturbations of the Phanerozoic, which included a first-order mass extinction known as the Hangenberg Event and one of the largest positive carbon isotope excursions in Earth history. The boundary is currently under review by the International Subcommissions on Devonian and Carboniferous Stratigraphy and any sections that contain expanded and more-or-less continuous deposition across this interval are badly needed. Unfortunately, many of the classical European D/C boundary sections are fairly thin across this interval and do not contain enough strata to obtain high-resolution data even with continuous bed-by-bed sampling.

The historical type area for the Mississippian Subsystem in the tri-state area of Missouri, Iowa, and Illinois contains thick Devonian and Mississippian deposits, and Southeastern Iowa contains some of the most extensive Upper Devonian and Lower Carboniferous strata in the world. These expanded D/C boundary successions allow for high-resolution sampling for both biostratigraphy and chemostratigraphy. Here, we present high-resolution, integrated conodont and d¹³C_carbdata from the H-28 and H-32 cores collected in southeastern Iowa. These data demonstrate the presence of the Hangenberg d¹³C_carbexcursion with values reaching up to +6.0‰ across nearly 58 meters of strata and that the region contains one of the most expanded D/C boundary intervals in the world.