Molybdenum isotope evidence for global ocean anoxia coupled with perturbations to the carbon cycle during the Early Jurassic
Molybdenum isotope evidence for global ocean anoxia coupled with perturbations to the carbon cycle during the Early Jurassic
Relatively brief periods of severe paleoenvironmental change during the Jurassic and Cretaceous were associated with the widespread accumulation of organic-rich marine deposits, termed oceanic anoxic events (OAEs). These intervals involved abrupt global warming of ?5–10 °C, higher rates of continental weathering, elevated extinction rates, and large-scale perturbations to the global carbon cycle. The major OAEs also overlapped temporally the emplacement of large igneous provinces. However, despite being known as OAEs, the extent of seawater anoxia at those times is undefined and the causative processes remain unclear. Here we show how changes in seawater molybdenum isotope ratios (a proxy for seawater anoxia) during the Toarcian (Early Jurassic) OAE define the onset and expansion of oxygen deficient conditions. Our data also place constraints on the areal extent of marine anoxia during the event and demonstrate that anoxia expanded and contracted periodically, broadly in line with precession-driven changes in ?13 Corg. Despite their intermittent occurrence over geological history, OAEs have an important contemporary relevance because the magnitude and high rates of environmental change then were broadly similar to those occurring at the present day
231-234
Pearce, Christopher R.
c83b6228-0b64-4f5a-a8ad-e5cd33a11de3
Cohen, Anthony S.
4d4f8583-0cc9-428a-9196-61d39cb1b90e
Coe, Angela L.
4312f508-81a2-465d-bbb1-d91738186ab4
Burton, Kevin W.
b17a2651-0697-4369-bfa7-ece9a9f0a3f1
2008
Pearce, Christopher R.
c83b6228-0b64-4f5a-a8ad-e5cd33a11de3
Cohen, Anthony S.
4d4f8583-0cc9-428a-9196-61d39cb1b90e
Coe, Angela L.
4312f508-81a2-465d-bbb1-d91738186ab4
Burton, Kevin W.
b17a2651-0697-4369-bfa7-ece9a9f0a3f1
Pearce, Christopher R., Cohen, Anthony S., Coe, Angela L. and Burton, Kevin W.
(2008)
Molybdenum isotope evidence for global ocean anoxia coupled with perturbations to the carbon cycle during the Early Jurassic.
Geology, 36 (3), .
(doi:10.1130/G24446A.1).
Abstract
Relatively brief periods of severe paleoenvironmental change during the Jurassic and Cretaceous were associated with the widespread accumulation of organic-rich marine deposits, termed oceanic anoxic events (OAEs). These intervals involved abrupt global warming of ?5–10 °C, higher rates of continental weathering, elevated extinction rates, and large-scale perturbations to the global carbon cycle. The major OAEs also overlapped temporally the emplacement of large igneous provinces. However, despite being known as OAEs, the extent of seawater anoxia at those times is undefined and the causative processes remain unclear. Here we show how changes in seawater molybdenum isotope ratios (a proxy for seawater anoxia) during the Toarcian (Early Jurassic) OAE define the onset and expansion of oxygen deficient conditions. Our data also place constraints on the areal extent of marine anoxia during the event and demonstrate that anoxia expanded and contracted periodically, broadly in line with precession-driven changes in ?13 Corg. Despite their intermittent occurrence over geological history, OAEs have an important contemporary relevance because the magnitude and high rates of environmental change then were broadly similar to those occurring at the present day
Text
Pearce_et_al_(2008).pdf
- Version of Record
Restricted to Repository staff only
More information
Published date: 2008
Organisations:
Paleooceanography & Palaeoclimate
Identifiers
Local EPrints ID: 342511
URI: http://eprints.soton.ac.uk/id/eprint/342511
ISSN: 0091-7613
PURE UUID: 49baa81c-5f83-4672-ab58-a73d63756732
Catalogue record
Date deposited: 07 Sep 2012 10:56
Last modified: 14 Mar 2024 11:53
Export record
Altmetrics
Contributors
Author:
Christopher R. Pearce
Author:
Anthony S. Cohen
Author:
Angela L. Coe
Author:
Kevin W. Burton
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics