Gold in the oceans through time

Ross R. Large*, Daniel D. Gregory, Jeffrey A. Steadman, Andrew G. Tomkins, Elena Lounejeva, Leonid V. Danyushevsky, Jacqueline A. Halpin, Valeriy Maslennikov, Patrick J. Sack, Indrani Mukherjee, Ron Berry, Arthur Hickman

*Corresponding author for this work

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

During sedimentation and diagenesis of carbonaceous shales in marine continental margin settings, Au is adsorbed from seawater and organic matter and becomes incorporated into sedimentary pyrite. LA-ICPMS analysis of over 4000 sedimentary pyrite grains in 308 samples from 33 locations around the world, grouped over 123 determined ages, has enabled us to track, in a first order sense, the Au content of the ocean over the last 3.5 billion years. Gold was enriched in the Meso- and Neoarchean oceans, several times above present values, then dropped by an order of magnitude from the first Great Oxidation Event (GOE1) through the Paleoproterozoic to reach a minimum value around 1600 Ma. Gold content of the oceans then rose, with perturbations, through the Meso- and Neoproterozoic, showing a steady rise at the end of the Proterozoic (800 to 520 Ma), which most likely represents the effects of the second Great Oxidation Event (GOE2). Gold in the oceans was at a maximum at 520 Ma, when oxygen in the oceans rose to match current maximum values. In the Archean and Proterozoic, the Au content of seawater correlates with the time distribution of high-Mg greenstone belts, black shales and banded iron formations, suggesting that increases in atmospheric oxygen and marine bio-productivity, combined with the higher background of Au in komatiitic and Mg-rich basalts were the first order causes of the pattern of Au enrichment in seawater. We suggest the lack of major Au deposits from 1800 to 800 Ma, is explained by the low levels of Au in the oceans during this period.

Original languageEnglish
Pages (from-to)139-150
Number of pages12
JournalEarth and Planetary Science Letters
Volume428
DOIs
Publication statusPublished - 15 Oct 2015
Externally publishedYes

Keywords

  • Au in seawater
  • sedimentary pyrite
  • orogenic Au deposits
  • sediment-hosted Au
  • boring billion
  • banded iron formation

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    Large, R. R., Gregory, D. D., Steadman, J. A., Tomkins, A. G., Lounejeva, E., Danyushevsky, L. V., ... Hickman, A. (2015). Gold in the oceans through time. Earth and Planetary Science Letters, 428, 139-150. https://doi.org/10.1016/j.epsl.2015.07.026