Influence of atmospheric oxygen on the late Paleozoic carbon cycle

Bradley D Cramer; Kate E Tierney

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Abstract

Influence of atmospheric oxygen on the late Paleozoic carbon cycle

Bradley D Cramer and Kate E Tierney

Abstracts with programs - Geological Society of America, Vol.39(6), p.85

Geological Society of America, 2007 annual meeting

10/2007

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Abstract

Levels of atmospheric oxygen fluctuated more widely during the late Paleozoic than any other time during the Phanerozoic. Current estimates suggest that atmospheric O (sub 2) levels may have been lower than 75% PAL O (sub 2) at the start of the Carboniferous and the end of the Permian, while an all-time high near 180% PAL O (sub 2) occurred in between. The possible connections between such rapid changes in atmospheric oxygen and the large scale ecological changes that took place during this interval have only begun to be explored. Here we discuss the influence of atmospheric oxygen concentrations on the global carbon cycle, and suggest that the difference between Carboniferous and Permian atmospheric oxygen levels was responsible for the difference between the delta (super 13) C (sub carb) records of the two periods. The Carboniferous delta (super 13) C (sub carb) record above the Visean is known for its instability and lack of protracted, sustained delta (super 13) C (sub carb) excursions. Conversely, the Permian is unique in its sustained, elevated delta (super 13) C (sub carb) values almost exclusively above +4 per mil. Based on an oceanographic model originally developed for the Silurian, oxygen levels above 100% PAL prohibit the possibility of organic carbon burial in the deep ocean. As a result, the global flux of organic carbon burial would have been highly susceptible to changes in sea level, providing a possible explanation for the highly variable carbon isotope record of the Carboniferous. Likewise, decreasing levels of atmospheric oxygen during the Permian allowed for deep ocean sequestration and burial of organic carbon as has recently been hypothesized by other research groups. At present, the records required to test this hypothesis are only now beginning to be produced. Without the ability to constrain more precisely the exact timing of changes in atmospheric oxygen levels and the delta (super 13) C (sub carb) record, the mechanistic connections between the various Earth systems will remain uncertain.

Carbon Cycle

Carbon Sequestration

Isotope Geochemistry

Paleoecology

Stratigraphy

C-13/C-12

carbon

Carboniferous

fluctuations

geochemical cycle

isotope ratios

isotopes

organic carbon

oxygen

paleoatmosphere

Paleozoic

Permian

sea-level changes

stable isotopes

upper Paleozoic

Details

Title: Subtitle: Influence of atmospheric oxygen on the late Paleozoic carbon cycle
Creators: Bradley D Cramer - Ohio State University, Department of Geological Sciences Columbus, OH USA United States
Kate E Tierney
Resource Type: Abstract
Publication Details: Abstracts with programs - Geological Society of America, Vol.39(6), p.85
Conference: Geological Society of America, 2007 annual meeting
Publisher: Geological Society of America (GSA)
ISSN: 0016-7592
Alternative title: Geological Society of America, 2007 annual meeting
Language: English
Date published: 10/2007
Academic Unit: Office Of The Provost; International Programs; Earth and Environmental Sciences
Record Identifier: 9984240792502771

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