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Primary gypsum nodules in a modern sabkha on the Mediterranean coast of Egypt

1979; Geological Society of America; Volume: 7; Issue: 7 Linguagem: Inglês

10.1130/0091-7613(1979)7 2.0.co;2

1943-2682

Ian M. West, Yehia A. Ali, M. E. Hilmy,

Coastal and Marine Dynamics

Research Article| July 01, 1979 Primary gypsum nodules in a modern sabkha on the Mediterranean coast of Egypt Ian M. West; Ian M. West 1Department of Geology, University of Southampton, Southampton, S09 5NH, England Search for other works by this author on: GSW Google Scholar Yehia A. Ali; Yehia A. Ali 1Department of Geology, University of Southampton, Southampton, S09 5NH, England Search for other works by this author on: GSW Google Scholar M. E. Hilmy M. E. Hilmy 2Department of Geology, Faculty of Science, University of Ain Shams, Cairo, Egypt Search for other works by this author on: GSW Google Scholar Author and Article Information Ian M. West 1Department of Geology, University of Southampton, Southampton, S09 5NH, England Yehia A. Ali 1Department of Geology, University of Southampton, Southampton, S09 5NH, England M. E. Hilmy 2Department of Geology, Faculty of Science, University of Ain Shams, Cairo, Egypt Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1979) 7 (7): 354–358. https://doi.org/10.1130/0091-7613(1979)7 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 Ian M. West, Yehia A. Ali, M. E. Hilmy; Primary gypsum nodules in a modern sabkha on the Mediterranean coast of Egypt. Geology 1979;; 7 (7): 354–358. doi: https://doi.org/10.1130/0091-7613(1979)7 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 Nodules of anhydrite in Holocene sabkhas of the Arabian Gulf and Baja California have been used as analogues to interpret calcium sulfate nodules in ancient rocks to be of sabkha origin. Nodules and incipient enterolithic veins of gypsum occur in a modern sabkha in Eqypt about halfway between Alexandria and El Alamein, in a depression between a modern and a Pleistocene beach ridge. The displacive gypsum is apparently being precipitated from hypersaline calcium sulfate-saturated interstitial water that increases in salinity as it rises by capillarity from the water table to the surface. Calcium and sulfate ions seem to be derived mainly from dissolution of pre-existing lagoonal gypsum beneath the water table. The nodules occur within a supratidal sand unit of a sabkha sequence capped by a gray, saline soil on which grow clumps of halophytes, separated by salt-encrusted flats. This discovery shows that calcium sulfate nodules can develop (1) within sediments of a region where the climate is almost semiarid rather than very arid, (2) as primary gypsum rather than as anhydrite, and (3) as a consequence of redistribution of calcium sulfate. 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.