Does large igneous province volcanism always perturb the mercury cycle? Comparing the records of Oceanic Anoxic Event 2 and the end-cretaceous to other Mesozoic events

Lawrence M.E. Percival, Hugh C. Jenkyns, Tamsin A. Mather, Alexander J. Dickson, Sietske J. Batenburg, Micha Ruhl, Stephen P. Hesselbo, Richard Barclay, Ian Jarvis, Stuart A. Robinson, Lineke Woelders

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Mercury (Hg) is increasingly being used as a sedimentary tracer of Large Igneous Province (LIP) volcanism, and supports hypotheses of a coincidence between the formation of several LIPs and episodes of mass extinction and major environmental perturbation. However, numerous important questions remain to be answered before Hg can be claimed as an unequivocal fingerprint of LIP volcanism, as well as an understanding of why some sedimentary records document clear Hg enrichment signals whilst others do not. Of particular importance is evaluating the impact of different volcanic styles on the global mercury cycle, as well as the role played by depositional processes in recording global Hg-cycle perturbations. Here, new mercury records of Cretaceous Oceanic Anoxic Event 2 (OAE 2: ∼94 Ma) and the latest Cretaceous (∼67-66.0 Ma) are presented. OAE 2 is associated with the emplacement of multiple, predominantly submarine, LIPs; the latest Cretaceous with subaerial volcanism of the Deccan Traps. Both of these connections are strongly supported by previously published trends towards unradiogenic osmium-(Os) isotope values in globally distributed sedimentary records. Hg data from both events show considerable variation between different locations, attributed to the effectiveness of different sediment types in registering the Hg signal, with lithologically homogeneous records documenting more clear Hg enrichments than sections with major changes in lithology such as limestones to claystones or organic-rich shales. Crucially, there is no geographically consistent signal of sedimentary Hg enrichment in stratigraphic records of either OAE 2 or the latest Cretaceous that matches Os-isotope evidence for LIP emplacement, indicating that volcanism did not cause a global Hg perturbation throughout the entire eruptive history of the LIPs formed at those times. It is suggested that the discrepancy between Os-isotope and Hg trends in records of OAE 2 is caused by the limited dispersal range of Hg emitted from submarine volcanoes compared to the global-scale distribution of Os. A similar lack of correlation between these two proxies in uppermost Cretaceous strata indicates that, although subaerial volcanism can perturb the global Hg cycle, not all subaerial eruptions will do so. These results highlight the variable impact of different volcanogenic processes on the efficiency of Hg dispersal across the globe. Factors that could influence the impact of LIP eruptions on the global mercury cycle include submarine versus subaerial volcanism, volcanic intensity or explosivity, and the potential contribution of thermogenic mercury from reactions between ascending magma and surrounding organic-rich sediments.
Original languageEnglish
Pages (from-to)799-860
JournalAmerican Journal of Science
Volume318
Issue number8
DOIs
Publication statusPublished - 1 Oct 2018
Externally publishedYes

Funding

We greatly appreciate reviews by JiˇríLaurin and Wang Zheng that have improved this manuscript, and must also thank Steve Grasby for discussions on the Meishan end-Permian mercury record. We gratefully acknowledge Alistair Crame and the British Antarctic Survey for their loan of samples from Seymour Island (Antarctica), the GTSnext project for support in collecting samples from Zumaia, Bill Simpson and Adrienne Stroup for access to the Utah samples, and Greg Wilson, Dave de Mar Jr., Denver Fowler, Regan Dunn, Jack Horner, Harold and Jean Isaacs, the Hell Creek III project, the University of Washington, the Museum of the Rockies, and the Montana Bureau of Land Management for their support and permission for sampling at East Gilbert Creek (Montana, USA). We must thank John Farmer and the University of Edinburgh for provision of geochemical standard material. We thank David Wray at the University of Greenwich for performing XRF analyses. We acknowledge the UK Natural Environment Research Council Grant NE/G01700X/1 (to Tamsin Mather), Ph. D. studentship NE/L501530/1 (to Lawrence Percival), Grant NE/H020756/1 (to Ian Jarvis), the European Commission (FP7/2007–2013 grant number 215458), National Science Foundation Grant EAR0643290 (to Bradley Sageman and Jennifer McElwain), Shell International Exploration and Production Inc., and the Leverhulme Trust for funding. We greatly appreciate reviews by Jiří Laurin and Wang Zheng that have improved this manuscript, and must also thank Steve Grasby for discussions on the Meishan end-Permian mercury record. We gratefully acknowledge Alistair Crame and the British Antarctic Survey for their loan of samples from Seymour Island (Antarctica), the GTSnext project for support in collecting samples from Zumaia, Bill Simpson and Adrienne Stroup for access to the Utah samples, and Greg Wilson, Dave de Mar Jr., Denver Fowler, Regan Dunn, Jack Horner, Harold and Jean Isaacs, the Hell Creek III project, the University of Washington, the Museum of the Rockies, and the Montana Bureau of Land Management for their support and permission for sampling at East Gilbert Creek (Montana, USA). We must thank John Farmer and the University of Edinburgh for provision of geochemical standard material. We thank David Wray at the University of Greenwich for performing XRF analyses. We acknowledge the UK Natural Environment Research Council Grant NE/G01700X/1 (to Tamsin Mather), Ph. D. studentship NE/L501530/1 (to Lawrence Percival), Grant NE/H020756/1 (to Ian Jarvis), the European Commission (FP7/2007-2013 grant number 215458), National Science Foundation Grant EAR0643290 (to Bradley Sageman and Jennifer McElwain), Shell International Exploration and Production Inc., and the Leverhulme Trust for funding.

FundersFunder number
FP7/2007
National Science Foundation
National Science FoundationEAR0643290
Shell Exploration and Production Company
Natural Environment Research CouncilNE/H020756/1, NE/L501530/1, NE/G01700X/1
Leverhulme Trust
European CommissionFP7/2007-2013, 215458

    Fingerprint

    Dive into the research topics of 'Does large igneous province volcanism always perturb the mercury cycle? Comparing the records of Oceanic Anoxic Event 2 and the end-cretaceous to other Mesozoic events'. Together they form a unique fingerprint.

    Cite this