Integrated conodont biostratigraphy and carbon isotope chemostratigraphy of the Mississippian Pahasapa Formation, Black Hills, South Dakota, U.S.A.
Braun, Matthew G.; Bancroft, Alyssa M.; Hogancamp, Nicholas J.; Stolfus, Brittany M.; Heath, Megan N.; Cramer, Bradley D.
Newsletters on Stratigraphy Volume 59 Number 3 (2026), p. 251 - 267
53 references
published: Aug 17, 2026
published online: Jan 15, 2026
manuscript accepted: Dec 12, 2025
manuscript revision requested: Oct 29, 2025
manuscript received: May 2, 2025
DOI: 10.1127/nos/0884
ArtNo. ESP026005903001, Price: 29.00 €
Abstract
The Black Hills, South Dakota, USA, expose thick packages of Devonian-Carboniferous carbonates that represent the shallow-water succession on the NW margin of the Transcontinental Arch. These carbonates are the up-ramp facies of the well-studied Devonian-Carboniferous Boundary succession in the Williston Basin farther to the NW. This basin margin succession is critical to developing a detailed sequence stratigraphic history of the Williston Basin and the U.S. Midcontinent but little chronostratigraphic information is available from these strata beyond their designation to the Mississippian Subsystem. Here, we sampled the uppermost beds of the Englewood Formation and ~ 60 m of the Pahasapa Formation for integrated conodont and carbon isotope biochemostratigraphy at the Spearfish Canyon section in the Black Hills including a total of 34 conodont and 203 carbonate carbon isotope samples. Conodont yields were generally poor, but the Mickelson Member of the Englewood Formation contained conodonts of the Siphonodella sandbergi Zone and the lower portion of the Pahasapa Formation contained Siphonodella crenulata Zone fauna. No discernable carbon isotope excursion was identified, and δ13C values persist above +3‰ throughout the top of the sampled interval. The Kinderhookian-Osagean Regional Stages boundary could not be placed precisely at the outcrop. However, there is no evidence that the portion of the Pahasapa Formation sampled extends any higher than within the global Tournaisian Stage.
Keywords
Early Mississippian • Tournaisian • conodont biostratigraphy • carbon isotope chemostratigraphy • chronostratigraphy • Black Hills South Dakota