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Global perturbation of the carbon cycle at the onset of the Miocene Climatic Optimum

Ann Holbourn, Wolfgang Kuhnt, Karlos G. D. Kochhann, Nils Andersen and K. J. Sebastian Meier
Global perturbation of the carbon cycle at the onset of the Miocene Climatic Optimum
Geology (Boulder) (February 2015) 43 (2): 123-126


The Miocene Climatic Optimum (MCO; ca. 17-14.7 Ma) represents one of several major interruptions in the long-term cooling trend of the past 50 m.y. To date, the processes driving high-amplitude climate variability and sustaining global warmth during this remarkable interval remain highly enigmatic. We present high-resolution benthic foraminiferal and bulk carbonate stable isotope records in an exceptional, continuous, carbonate-rich sedimentary archive (Integrated Ocean Drilling Program Site U1337, eastern equatorial Pacific Ocean), which offer a new view of climate evolution over the onset of the MCO. A sharp decline in delta (super 18) O and delta (super 13) C at ca. 16.9 Ma, contemporaneous with a massive increase in carbonate dissolution, demonstrates that abrupt warming was coupled to an intense perturbation of the carbon cycle. The rapid recovery in delta (super 13) C at ca. 16.7 Ma, approximately 250 k.y. after the beginning of the MCO, marks the onset of the first carbon isotope maximum within the long-lasting "Monterey Excursion." These results lend support to the notion that atmospheric pCO (sub 2) variations drove profound changes in the global carbon reservoir through the MCO, implying a delicate balance between changing CO (sub 2) fluxes, rates of silicate weathering, and global carbon sequestration. Comparison with a high-resolution delta (super 13) C record spanning the onset of the Cretaceous Oceanic Anoxic Event 1a ( approximately 120 m.y. ago) reveals common forcing factors and climatic responses, providing a long-term perspective to understand climate-carbon cycle feedbacks during warmer periods of Earth's climate with markedly different atmospheric CO (sub 2) concentrations.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 43
Serial Issue: 2
Title: Global perturbation of the carbon cycle at the onset of the Miocene Climatic Optimum
Affiliation: Christian-Albrechts University of Kiel, Institute of Geosciences, Kiel, Germany
Pages: 123-126
Published: 201502
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 30
Accession Number: 2015-016280
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2015050
Illustration Description: illus.
N03°49'60" - N03°49'60", W123°12'22" - W123°12'22"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, 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: 201508
Program Name: IODPIntegrated Ocean Drilling Program
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