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CO (sub 2) -induced climate forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2

Sarah J. Baker, Claire M. Belcher, Richard S. Barclay, Stephen P. Hesselbo, Jiri Laurin and Bradley B. Sageman
CO (sub 2) -induced climate forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2
Geological Society of America Bulletin (June 2019) Pre-Issue Publication


Cretaceous oceanic anoxic event 2 (OAE2) is thought to have been contemporary with extensive volcanism and the release of large quantities of volcanic CO (sub 2) capable of triggering marine anoxia through a series of biogeochemical feedbacks. High-resolution reconstructions of atmospheric CO (sub 2) concentrations across the initiation of OAE2 suggest that there were also two distinct pulses of CO (sub 2) drawdown coeval with increased organic carbon burial. These fluctuations in CO (sub 2) likely led to significant climatic changes, including fluctuations in temperatures and the hydrological cycle. Paleofire proxy records suggest that wildfire was a common occurrence throughout the Cretaceous Period, likely fueled by the estimated high atmospheric O (sub 2) concentrations at this time. However, over geological time scales, the likelihood and behavior of fire are also controlled by other factors such as climate, implying that CO (sub 2) -driven climate changes should also be observable in the fossil charcoal record. We tested this hypothesis and present a high-resolution study of fire history through the use of fossil charcoal abundances across the OAE2 onset, and we compared our records to the estimated CO (sub 2) fluctuations published from the same study sites. Our study illustrates that inferred wildfire activity appears to relate to changes in CO (sub 2) occurring across the onset of OAE2, where periods of CO (sub 2) drawdown may have enabled an increase in fire activity through suppression of the hydrological cycle. Our study provides further insight into the relationships between rapid changes in the carbon cycle, climate, and wildfire activity, illustrating that CO (sub 2) and climate changes related to inferred wildfire activity can be detected despite the estimated high Cretaceous atmospheric O (sub 2) concentrations.

ISSN: 0016-7606
EISSN: 1943-2674
Serial Title: Geological Society of America Bulletin
Serial Volume: Pre-Issue Publication
Title: CO (sub 2) -induced climate forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2
Affiliation: University of Exeter, Hatherly Laboratories, Exeter, United Kingdom
Published: 20190613
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 94
Accession Number: 2019-081174
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch map
N37°45'00" - N38°30'00", W105°04'60" - W104°04'60"
Secondary Affiliation: Smithsonian Institution National Museum of Natural History, USA, United StatesAcademy of Sciences of the Czech Republic, Institute of Geophysics, CZE, Czech RepublicNorthwestern University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201943
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