Halite-Anhydrite Seasonal Layers in the Middle Devonian Prairie Evaporite Formation, Saskatchewan, Canada

Research Article| April 01, 1966 Halite-Anhydrite Seasonal Layers in the Middle Devonian Prairie Evaporite Formation, Saskatchewan, Canada N. C WARDLAW; N. C WARDLAW University of Saskatchewan, Canada Search for other works by this author on: GSW Google Scholar W. M SCHWERDTNER W. M SCHWERDTNER University of Saskatchewan, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information N. C WARDLAW University of Saskatchewan, Canada W. M SCHWERDTNER University of Saskatchewan, Canada Publisher: Geological Society of America Received: 07 Dec 1964 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1966, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1966) 77 (4): 331–342. https://doi.org/10.1130/0016-7606(1966)77[331:HSLITM]2.0.CO;2 Article history Received: 07 Dec 1964 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation N. C WARDLAW, W. M SCHWERDTNER; Halite-Anhydrite Seasonal Layers in the Middle Devonian Prairie Evaporite Formation, Saskatchewan, Canada. GSA Bulletin 1966;; 77 (4): 331–342. doi: https://doi.org/10.1130/0016-7606(1966)77[331:HSLITM]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 SocietyGSA Bulletin Search Advanced Search Abstract In the lower half of the Devonian Prairie Evaporite Formation, halite units 2–10 cm thick alternate with anhydrite units, most of which are less than 1 cm thick. Such halite-anhydrite alternations are thought to result from seasonal changes in the basin waters during deposition and are called seasonal layers.Halite occurs as opaque “chevron” grains with abundant liquid inclusions and as transparent grains without liquid inclusions. The chevron grains are conspicuously elongated perpendicular to bedding and contain a distinctive chevron structure caused by zones of liquid inclusions. They started growth as cubes, which were oriented with (110) or (111) approximately parallel to bedding; subsequently growth took place on only two or three upward-directed faces. These grains are considered to be primary and grown on the Devonian sea floor. Similar chevron grains were produced artificially during competitive growth into a salt solution.Inclusion-free halite grains tend to have irregular shape and no elongation perpendicular to bedding. They are larger than associated chevron grains and locally appear to have replaced them. Their bromide content is higher than that of associated chevron grains.Bromide analyses of successive chevron grains above an anhydrite layer show a rapid increase to a maximum value and then a steady decrease as the overlying anhydrite layer is approached. This variation of bromide is most satisfactorily explained by influxes of sea water or brine. Following the deposition of anhydrite, the influxes increased markedly in salinity and then decreased before deposition of the overlying anhydrite layer. 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.