Rapid climate change and associated black shale deposition during past greenhouse conditions; the lower Albian Oceanic Anoxic Event 1b

Author(s): Hofmann, Peter; Stuesser, I.; Wagner, Thomas; Schouten, S.; Sinninghe Damsté, J. S.; Wallmann, K.
Author Affiliation(s): Primary:
University of Cologne, Department of Geology and Mineralogy, Cologne, Federal Republic of Germany
University of Newcastle, United Kingdom
Royal Netherlands Institute of Sea Research, Netherlands
University of Kiel, Federal Republic of Germany
Volume Title: AGU 2006 fall meeting
Source: Eos, Transactions, American Geophysical Union, 87( Fall Meeting Suppl.); American Geophysical Union 2006 fall meeting, San Francisco, CA, Dec. 11-15, 2006. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0096-3941 CODEN: EOSTAJ
Note: In English
Summary: The lower Albian Oceanic Anoxic Event 1b (OAE 1b) represents a distinct short lived perturbation (45 kyrs) of the global carbon cycle during Cretaceous greenhouse conditions. The event is recognized based on negative carbon isotope excursions recorded in carbonates, bulk organic matter and molecular marker components attributed to marine and terrestrial derived organic matter. We report data from DSDP Site 545 Mazagan Plateau and the Vocontian Basin of Southern France indicating a sudden increase in sea surface temperature by 3 degree Celsius within a few hundred years based on Tex 86 measurements. Associated is a distinct increase in marine productivity leading to black shale deposition and an elevated flux of continental derived nutrients to the Atlantic and Tethys Ocean documented by inorganic geochemical proxies. Our data are in good agreement with a period characterized by an enhanced hydrological in tropical and subtropical regions during the event. Results from box model experiments show that the distinct geochemical signature of OAE 1b is best explained by the release of methane from gas hydrates. Based on the modelling results the release of approximately one tens of the amount of gas hydrates known today is required to explain the observed carbon isotope excursions.
Year of Publication: 2006
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Albian; Atlantic Ocean; Black shale; Carbon; Carbon cycle; Clastic rocks; Climate change; Cretaceous; DSDP Site 545; Deep Sea Drilling Project; Depositional environment; Gas hydrates; Geochemical cycle; Global; Greenhouse effect; IPOD; Leg 79; Lower Cretaceous; Mazagan Plateau; Mesozoic; North Atlantic; Nutrients; Oceanic anoxic events; Paleoenvironment; Sedimentary rocks; Tropical environment; Vocontian Trough
Coordinates: N333951 N333952 W0092152 W0092153
Record ID: 2009063359
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