Abstract
High-resolution paired organic and carbonate carbon isotope chemostratigraphy of the Hangenberg event from H28 and Hh32 Cores in southeast Iowa
Abstracts with programs - Geological Society of America, Vol.52(6)
Geological Society of America, 2020 annual meeting; GSA 2020 connects online
10/2020
DOI: 10.1130/abs/2020AM-359740
Abstract
This study uses new high-resolution organic (delta (super 13) C (sub org) ) and carbonate (delta (super 13) C (sub carb) ) carbon isotope data from shelf deposits in Iowa to explore the Hangenberg Event, a mass extinction event and carbon isotope excursion spanning the Devonian-Carboniferous boundary. Biostratigraphic correlation of conodonts between the standard European section and strata in Iowa place the early and middle Hangenberg Crises in the siltstones and shales of the upper English River Formation (upper B. ultimus Zone) and the late Hangenberg Crisis in the limestone of the lower Louisiana Formation (lower-mid kockeli Zone). Our results show decoupling of the delta (super 13) C (sub carb) and delta (super 13) C (sub org) curves followed by a positive excursion in both carbonate and organic carbon isotopes. The curves decouple in the upper English River Formation, where delta (super 13) C (sub org) values decrease and values of delta (super 13) C (sub carb) increase simultaneously. Further investigation into the factors controlling the isotopic fractionation of carbon using Delta (super 13) C led us to conclude that the negative delta (super 13) C (sub org) excursion is a global signal caused by the addition of chemoautotrophic organisms to the sediment. In the overlying Louisiana Formation delta (super 13) C (sub carb) and delta (super 13) C (sub org) values reach sustained peaks of +6 ppm and -26 ppm, respectively. Calculated f (sub org) values increase in the Louisiana Formation, corresponding with the positive delta (super 13) C (sub carb) excursion and indicating the most likely cause of the positive carbon isotope excursion is increased organic carbon burial. This study emphasizes the importance of high-resolution sampling, as it was a critical component of our ability to decipher short-term changes in the carbon cycle.
Details
- Title: Subtitle
- High-resolution paired organic and carbonate carbon isotope chemostratigraphy of the Hangenberg event from H28 and Hh32 Cores in southeast Iowa
- Creators
- Megan N Heath - University of IowaBradley D CramerBrittany M StolfusRyan J ClarkJames E DayStephanie A Tassier-SurineGwen L Barnes
- Resource Type
- Abstract
- Publication Details
- Abstracts with programs - Geological Society of America, Vol.52(6)
- Conference
- Geological Society of America, 2020 annual meeting; GSA 2020 connects online
- Publisher
- Geological Society of America (GSA)
- DOI
- 10.1130/abs/2020AM-359740
- ISSN
- 0016-7592
- Alternative title
- Geological Society of America, 2020 annual meeting; GSA 2020 connects online
- Language
- English
- Date published
- 10/2020
- Academic Unit
- IIHR--Hydroscience and Engineering; International Programs; Earth and Environmental Sciences; Office Of The Provost
- Record Identifier
- 9984229966202771
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