Stable Cl isotopes in subduction-zone pore waters: Implications for fluid-rock reactions and the cycling of chlorine

Abstract

Research Article| August 01, 1995 Stable Cl isotopes in subduction-zone pore waters: Implications for fluid-rock reactions and the cycling of chlorine Barbara Ransom; Barbara Ransom 1Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 Search for other works by this author on: GSW Google Scholar Arthur J. Spivack; Arthur J. Spivack 1Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 Search for other works by this author on: GSW Google Scholar Miriam Kastner Miriam Kastner 1Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 Search for other works by this author on: GSW Google Scholar Author and Article Information Barbara Ransom 1Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 Arthur J. Spivack 1Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 Miriam Kastner 1Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1995) 23 (8): 715–718. https://doi.org/10.1130/0091-7613(1995)023<0715:SCIISZ>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 Barbara Ransom, Arthur J. Spivack, Miriam Kastner; Stable Cl isotopes in subduction-zone pore waters: Implications for fluid-rock reactions and the cycling of chlorine. Geology 1995;; 23 (8): 715–718. doi: https://doi.org/10.1130/0091-7613(1995)023<0715:SCIISZ>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 Stable Cl isotope ratios, measured in marine pore waters associated with the Barbados and Nankai subduction zones, extend significantly (to ∼−8‰) the range of δ37Cl values reported for natural waters. These relatively large negative values, together with geologic and chemical evidence from Barbados and Nankai and recent laboratory data showing that hydrous silicate minerals (i.e., those with structural OH sites) are enriched up to 7.5‰ in 37Cl relative to seawater, strongly suggest that the isotopic composition of Cl in pore waters from subduction zones reflects diagenetic and metamorphic dehydration and transformation reactions. These reactions involve clays and/or other hydrous silicate phases at depth in the fluid source regions. Chlorine therefore cannot be considered geochemically conservative in these systems. The uptake of Cl by hydrous phases provides a mechanism by which Cl can be cycled into the mantle through subduction zones. Thus, stable Cl isotopes should help in determining the extent to which Cl and companion excess volatiles like H2O and CO2 cycle between the crust and mantle. 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.