The role of SO4 in the switch from calcite to aragonite seas

Abstract

Research Article| April 01, 2011 The role of SO4 in the switch from calcite to aragonite seas P. Bots; P. Bots 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK Search for other works by this author on: GSW Google Scholar L.G. Benning; L.G. Benning 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK Search for other works by this author on: GSW Google Scholar R.E.M. Rickaby; R.E.M. Rickaby 2Department of Earth Sciences, Oxford University, Parks Road, Oxford OX1 3PR, UK Search for other works by this author on: GSW Google Scholar S. Shaw S. Shaw 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK Search for other works by this author on: GSW Google Scholar Author and Article Information P. Bots 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK L.G. Benning 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK R.E.M. Rickaby 2Department of Earth Sciences, Oxford University, Parks Road, Oxford OX1 3PR, UK S. Shaw 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK Publisher: Geological Society of America Received: 28 Jul 2010 Revision Received: 13 Oct 2010 Accepted: 08 Nov 2010 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2011 Geological Society of America Geology (2011) 39 (4): 331–334. https://doi.org/10.1130/G31619.1 Article history Received: 28 Jul 2010 Revision Received: 13 Oct 2010 Accepted: 08 Nov 2010 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation P. Bots, L.G. Benning, R.E.M. Rickaby, S. Shaw; The role of SO4 in the switch from calcite to aragonite seas. Geology 2011;; 39 (4): 331–334. doi: https://doi.org/10.1130/G31619.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Throughout the Phanerozoic, the primary inorganic marine calcium carbonate mineralogy oscillated between calcite and aragonite, reflecting changes in seawater chemistry. These variations in seawater composition also appear to have influenced the evolution of calcifying organisms. However, the processes controlling these mineralogical and biological changes are poorly constrained. Previous work has focused mainly on the Mg/Ca ratio in seawater as the primary driver. Here, we examine the role of dissolved SO4 in these processes by performing controlled laboratory precipitation experiments and geochemical modeling of evaporite formation. We show that an increase in dissolved SO4 decreases the Mg/Ca ratio at which calcite is destabilized and aragonite becomes the dominant CaCO3 polymorph. Our data suggest that the Mg/Ca and SO4 thresholds for formation of calcite seas are significantly lower than previous estimates and are mutually dependent. This shows that our understanding of Phanerozoic changes in seawater chemistry and the models relating this to primary CaCO3 mineralogy need reevaluation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.