Sulfur isotopic profile through the oceanic crust: Sulfur mobility and seawater-crustal sulfur exchange during hydrothermal alteration

Research Article| July 01, 1995 Sulfur isotopic profile through the oceanic crust: Sulfur mobility and seawater-crustal sulfur exchange during hydrothermal alteration Jeffrey C. Alt Jeffrey C. Alt 1Department of Geological Sciences, 1006 C. C. Little Building, University of Michigan, Ann Arbor, Michigan 48109-1063 Search for other works by this author on: GSW Google Scholar Author and Article Information Jeffrey C. Alt 1Department of Geological Sciences, 1006 C. C. Little Building, University of Michigan, Ann Arbor, Michigan 48109-1063 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 (7): 585–588. https://doi.org/10.1130/0091-7613(1995)023<0585:SIPTTO>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 Email Permissions Search Site Citation Jeffrey C. Alt; Sulfur isotopic profile through the oceanic crust: Sulfur mobility and seawater-crustal sulfur exchange during hydrothermal alteration. Geology 1995;; 23 (7): 585–588. doi: https://doi.org/10.1130/0091-7613(1995)023<0585:SIPTTO>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 Measurements of the abundance of anhydrite and pyrite veins and the distribution of alteration types in oceanic basement enable estimates of global mass and isotopic fluxes of sulfur during hydrothermal alteration of oceanic crust. Fluxes of 2.5 × 10 12 g/yr S (δ-34 S = 2.7%) from the volcanic section to seawater and 2.1 × 1012 g/yr of seawater S (21%) into the crust result in an insignificant change in the S content of altered ocean crust. These are clearly second-order fluxes compared to the riverine input of S to the oceans and the output of sedimentary pyrite. Most of the anhydrite that forms in the high-temperature axial convection cell must later be dissolved at lower temperatures during off-axis circulation. The mean δ-34 S of altered oceanic basement is 0.9%, only slightly changed from the primary value of 0.1%. Unless S is preferentially mobilized from 34S-rich sulfide deposits or mineralized zones, subduction of altered basaltic crust is unlikely to be the source of high δ34S values of arc volcanic rocks (∼4%), but could contribute to isotopic heterogeneities of S in the 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.