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

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

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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 O-18 and delta C-13 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 C-13 at ca. 16.7 Ma, similar to 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(2) variations drove profound changes in the global carbon reservoir through the MCO, implying a delicate balance between changing CO2 fluxes, rates of silicate weathering, and global carbon sequestration. Comparison with a high-resolution delta C-13 record spanning the onset of the Cretaceous Oceanic Anoxic Event 1a (similar to 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 CO2 concentrations.

Document Type: Article
Additional Information: Times Cited: 5
Research affiliation: Kiel University
Kiel University > Kiel Marine Science
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
ISSN: 0091-7613
Projects: Future Ocean
Date Deposited: 18 Oct 2016 03:46
Last Modified: 23 Feb 2018 09:37

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