Relative precipitation rates of aragonite and Mg calcite from seawater: Temperature or carbonate ion control?

Abstract

Research Article| February 01, 1987 Relative precipitation rates of aragonite and Mg calcite from seawater: Temperature or carbonate ion control? Elizabeth A. Burton; Elizabeth A. Burton 1Department of Earth and Planetary Sciences Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar Lynn M. Walter Lynn M. Walter 1Department of Earth and Planetary Sciences Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar Author and Article Information Elizabeth A. Burton 1Department of Earth and Planetary Sciences Washington University, St. Louis, Missouri 63130 Lynn M. Walter 1Department of Earth and Planetary Sciences Washington University, St. Louis, Missouri 63130 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1987) 15 (2): 111–114. https://doi.org/10.1130/0091-7613(1987)15<111:RPROAA>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Elizabeth A. Burton, Lynn M. Walter; Relative precipitation rates of aragonite and Mg calcite from seawater: Temperature or carbonate ion control?. Geology 1987;; 15 (2): 111–114. doi: https://doi.org/10.1130/0091-7613(1987)15<111:RPROAA>2.0.CO;2 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 The temperature and degree of carbonate mineral supersaturation (CO3−2 ion concentration) of seawater are the two most likely controlling variables on the compositions of recent marine carbonate cements. The relative importance of these variables is difficult to assess in nature because they have similar trends with depth (0–1500 m) and latitude in modern oceans. We carried out laboratory experiments to investigate the relative growth rates of calcite, Mg calcite, and aragonite in seawater as functions of both temperature (5, 25, and 37 °C) and of carbonate ion concentration (2.5 to 15 times supersaturated with respect to calcite).The precipitation rates of aragonite relative to those of calcite increase strongly with increasing temperature and are not affected greatly by changes in saturation state. At 5 °C, calcite precipitation rates are nearly equivalent to those of aragonite, regardless of the degree of saturation. At both 25 and 37 °C, aragonite precipitation rates are much more rapid than those of calcite (up to a factor of 4), except at very low saturation states. Calcite compositions vary from less than 5 mol% MgCO3 at 5 °C to 14 mol% MgCO3 at 37 °C. Our results suggest that the well-documented shift toward precipitation of lower mol% Mg calcite and the decrease in abundance of aragonite cements with increasing oceanic depth and latitude can be attributed largely to lower temperatures. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.