Skip to main content

Research Repository

Advanced Search

Black shale deposition, atmospheric CO2 drawdown, and cooling during the Cenomanian-Turonian Oceanic Anoxic Event

Jarvis, I.; Lignum, J.S.; Gröcke, D.R.; Jenkyns, H.C.; Pearce, M.A.

Black shale deposition, atmospheric CO2 drawdown, and cooling during the Cenomanian-Turonian Oceanic Anoxic Event Thumbnail


Authors

I. Jarvis

J.S. Lignum

H.C. Jenkyns

M.A. Pearce



Abstract

[1] Oceanic Anoxic Event 2 (OAE2), spanning the Cenomanian-Turonian boundary (CTB), represents one of the largest perturbations in the global carbon cycle in the last 100 Myr. The δ13Ccarb, δ13Corg, and δ18O chemostratigraphy of a black shale–bearing CTB succession in the Vocontian Basin of France is described and correlated at high resolution to the European CTB reference section at Eastbourne, England, and to successions in Germany, the equatorial and midlatitude proto-North Atlantic, and the U.S. Western Interior Seaway (WIS). Δ13C (offset between δ13Ccarb and δ13Corg) is shown to be a good pCO2 proxy that is consistent with pCO2 records obtained using biomarker δ13C data from Atlantic black shales and leaf stomata data from WIS sections. Boreal chalk δ18O records show sea surface temperature (SST) changes that closely follow the Δ13C pCO2 proxy and confirm TEX86 results from deep ocean sites. Rising pCO2 and SST during the Late Cenomanian is attributed to volcanic degassing; pCO2 and SST maxima occurred at the onset of black shale deposition, followed by falling pCO2 and cooling due to carbon sequestration by marine organic productivity and preservation, and increased silicate weathering. A marked pCO2 minimum (∼25% fall) occurred with a SST minimum (Plenus Cold Event) showing >4°C of cooling in ∼40 kyr. Renewed increases in pCO2, SST, and δ13C during latest Cenomanian black shale deposition suggest that a continuing volcanogenic CO2 flux overrode further drawdown effects. Maximum pCO2 and SST followed the end of OAE2, associated with a falling nutrient supply during the Early Turonian eustatic highstand.

Citation

Jarvis, I., Lignum, J., Gröcke, D., Jenkyns, H., & Pearce, M. (2011). Black shale deposition, atmospheric CO2 drawdown, and cooling during the Cenomanian-Turonian Oceanic Anoxic Event. Paleoceanography, 26(3), Article PA3201. https://doi.org/10.1029/2010pa002081

Journal Article Type Article
Acceptance Date Apr 13, 2011
Online Publication Date Jul 19, 2011
Publication Date Sep 1, 2011
Deposit Date Mar 5, 2012
Publicly Available Date Mar 29, 2024
Journal Paleoceanography
Print ISSN 0883-8305
Electronic ISSN 1944-9186
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
Volume 26
Issue 3
Article Number PA3201
DOI https://doi.org/10.1029/2010pa002081

Files

Published Journal Article (2.4 Mb)
PDF

Copyright Statement
Jarvis, I., J. S. Lignum, D. R. Gröcke, H. C. Jenkyns, and M. A. Pearce (2011), Black shale deposition, atmospheric CO2 drawdown, and cooling during the Cenomanian-Turonian Oceanic Anoxic Event, Paleoceanography, 26, PA3201, doi:10.1029/2010PA002081. To view the published open abstract, go to https://doi.org and enter the DOI





You might also like



Downloadable Citations