The University of Southampton
University of Southampton Institutional Repository

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
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
0091-7613
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
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), 231-234. (doi:10.1130/G24446A.1).

Record type: Article

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

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×