Abstract
Chasing the Hangenberg and Kinderhook-Osage boundary excursions in the U.S. Midcontinent; "dumbbell stratigraphy" and the Sub-Burlington Unconformity
Abstracts with programs - Geological Society of America, Vol.53(5)
Geological Society of America, 2021 annual meeting; GSA connects 2021
10/2021
DOI: 10.1130/abs/2021AM-369610
Abstract
The latest Devonian to Early Mississippian (Famennian to Osagean) was marked by significant changes in the ocean-atmosphere-biosphere system that include two major biogeochemical events. This interval records two of the largest positive delta (super 13) C excursions of the Phanerozoic; the Hangenberg excursion (which occurs at the Devonian-Mississippian boundary) and the Kinderhook-Osage Boundary Excursion (KOBE) which spans the K-O boundary. Some of the best exposed strata of this age are located in the U.S. midcontinent, notably the Iowa, Illinois, and Missouri tri-state region, which includes the type area for the Kinderhookian Stage. Deposition occurred across a shallow carbonate shelf with a northeast-southwest depositional strike; Inner Shelf facies in central Iowa transition to Proximal/Central Middle Shelf facies in southeast Iowa and northern Missouri, Distal Middle Shelf facies in western Illinois and central Missouri, and eventually transitioning to Outer Shelf facies farther to the south/southeast. Forming a dumbbell-like pattern, strata are thinnest in the Central Middle Shelf and thicken both northwestward and southeastward into the Inner Shelf and Distal Middle Shelf deposits. This condensed interval of the Central Middle Shelf greatly complicates stratigraphic correlations across the state of Iowa and into Missouri/Illinois. Through integration of sequence stratigraphy, delta (super 13) C chemostratigraphy, and conodont biostratigraphy, results from the tri-state area indicate an expanded record of the Devonian-Mississippian boundary and the Hangenberg excursion, whereas the KOBE is absent and the K-O boundary is marked by a significant hiatal surface. Conversely, up-ramp in central Iowa an expanded record of the K-O boundary and the KOBE is present, while the Devonian-Mississippian boundary is more condensed and the Hangenberg excursion is absent. This shelf geometry, resembling a dumbbell shape, suggests the lack of stratigraphy across the K-O boundary (sub-Burlington unconformity) was unlikely to have been the result of subaerial exposure.
Details
- Title: Subtitle
- Chasing the Hangenberg and Kinderhook-Osage boundary excursions in the U.S. Midcontinent; "dumbbell stratigraphy" and the Sub-Burlington Unconformity
- Creators
- Matthew Braun - University of IowaBradley CramerBrittany StolfusMadysen H. GilbertMegan HeathGwen BarnesRyan J. ClarkJames E. DayBrian WitzkeNicholas HogancampAlyssa M. BancroftStephanie Tassier-Surine
- Resource Type
- Abstract
- Publication Details
- Abstracts with programs - Geological Society of America, Vol.53(5)
- Conference
- Geological Society of America, 2021 annual meeting; GSA connects 2021
- Publisher
- Geological Society of America (GSA)
- DOI
- 10.1130/abs/2021AM-369610
- ISSN
- 0016-7592
- Alternative title
- Geological Society of America, 2021 annual meeting; GSA connects 2021
- Language
- English
- Date published
- 10/2021
- Academic Unit
- Earth and Environmental Sciences; Iowa Geological Survey; IIHR--Hydroscience and Engineering; International Programs
- Record Identifier
- 9984702715602771
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