Secular variation in seawater chemistry: An explanation for the coupled secular variation in the mineralogies of marine limestones and potash evaporites over the past 600 m.y.

Abstract

Research Article| March 01, 1996 Secular variation in seawater chemistry: An explanation for the coupled secular variation in the mineralogies of marine limestones and potash evaporites over the past 600 m.y. Lawrence A. Hardie Lawrence A. Hardie 1Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, Maryland 21218 Search for other works by this author on: GSW Google Scholar Geology (1996) 24 (3): 279–283. https://doi.org/10.1130/0091-7613(1996)024<0279:SVISCA>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Lawrence A. Hardie; Secular variation in seawater chemistry: An explanation for the coupled secular variation in the mineralogies of marine limestones and potash evaporites over the past 600 m.y.. Geology 1996;; 24 (3): 279–283. doi: https://doi.org/10.1130/0091-7613(1996)024<0279:SVISCA>2.3.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 Secular changes in the mineralogies of marine nonskeletal limestones and potash evaporites occur in phase on a 100–200 m.y. time scale such that periods of "aragonite seas" are synchronized with MgSO4 evaporites and periods of "calcite seas" with KCl evaporites. It is proposed that these coupled changes are the result of secular variation in seawater chemistry controlled primarily by fluctuations in the mid-ocean ridge hydrothermal brine flux, which in turn have been driven by fluctuations in the rate of ocean crust production. Quantitative predictions based on this hypothesis yield secular variation in limestone and potash evaporite mineralogies that closely match the observed variation over the past 600 m.y., providing strong support for the thesis that seawater chemistry, rather than remaining constant, has oscillated significantly over geologic time. This content is PDF only. Please click on the PDF icon to access. 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.