Research Article| November 01, 1996 On the secular variations in the composition of Phanerozoic marine potash evaporites Heinrich D. Holland; Heinrich D. Holland 1Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138-2902 Search for other works by this author on: GSW Google Scholar Juske Horita; Juske Horita 2Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110 Search for other works by this author on: GSW Google Scholar William E. Seyfried, Jr William E. Seyfried, Jr 3Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar Author and Article Information Heinrich D. Holland 1Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138-2902 Juske Horita 2Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110 William E. Seyfried, Jr 3Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1996) 24 (11): 993–996. https://doi.org/10.1130/0091-7613(1996)024<0993:OTSVIT>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 Heinrich D. Holland, Juske Horita, William E. Seyfried; On the secular variations in the composition of Phanerozoic marine potash evaporites. Geology 1996;; 24 (11): 993–996. doi: https://doi.org/10.1130/0091-7613(1996)024<0993:OTSVIT>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 In a recent paper, L. A. Hardie proposed that the secular changes in the mineralogy of marine nonskeletal limestones and in the mineralogy of marine potash evaporites during the Phanerozoic are the result of changes in the composition of seawater caused primarily by fluctuations in the flux of seawater through mid-ocean ridges. He suggested that even quite small variations (25%) in this flux have a profound effect on the composition of seawater. We show that the effects of changes in the hydrothermal flux are much smaller than he proposed. Nevertheless, a doubling of the hydrothermal flux could probably alter the composition of seawater sufficiently to affect the mineralogy of marine potash evaporites. An alternative explanation for the variations in the mineralogy of these deposits invokes differences in the degree of dolomitization during the evaporation of seawater. The apparent near constancy of the K+ content of seawater during the Phanerozoic supports this hypothesis. It seems likely that during periods of rapid seafloor spreading the rate of seawater cycling is greater than today, that sea level is higher, that very large carbonate platforms are more abundant, and that changes in seawater chemistry together with increases in dolomitization during the evaporation of seawater lead to MgSO4-free potash deposits. The relative importance of these several effects can probably be determined with certainty only when we have analyses of relatively unaltered seawater from the several Phanerozoic periods. 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.
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Holland et al. (1996) studied this question.