Research Article| July 01, 1998 Authigenic carbonates from the Cascadia subduction zone and their relation to gas hydrate stability Gerhard Bohrmann; Gerhard Bohrmann 1GEOMAR, Forschungszentrum für marine Geowissenschaften, Wischhofstrasse 1-3, 24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Jens Greinert; Jens Greinert 1GEOMAR, Forschungszentrum für marine Geowissenschaften, Wischhofstrasse 1-3, 24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Erwin Suess; Erwin Suess 1GEOMAR, Forschungszentrum für marine Geowissenschaften, Wischhofstrasse 1-3, 24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Marta Torres Marta Torres 2College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Admin Building, Corvallis, Oregon 97331-5503 Search for other works by this author on: GSW Google Scholar Author and Article Information Gerhard Bohrmann 1GEOMAR, Forschungszentrum für marine Geowissenschaften, Wischhofstrasse 1-3, 24148 Kiel, Germany Jens Greinert 1GEOMAR, Forschungszentrum für marine Geowissenschaften, Wischhofstrasse 1-3, 24148 Kiel, Germany Erwin Suess 1GEOMAR, Forschungszentrum für marine Geowissenschaften, Wischhofstrasse 1-3, 24148 Kiel, Germany Marta Torres 2College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Admin Building, Corvallis, Oregon 97331-5503 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (7): 647–650. https://doi.org/10.1130/0091-7613(1998)026<0647:ACFTCS>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 Gerhard Bohrmann, Jens Greinert, Erwin Suess, Marta Torres; Authigenic carbonates from the Cascadia subduction zone and their relation to gas hydrate stability. Geology 1998;; 26 (7): 647–650. doi: https://doi.org/10.1130/0091-7613(1998)026<0647:ACFTCS>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 Authigenic carbonates are intercalated with massive gas hydrates in sediments of the Cascadia margin. The deposits were recovered from the uppermost 50 cm of sediments on the southern summit of the Hydrate Ridge during the RV Sonne cruise SO110. Two carbonate lithologies that differ in chemistry, mineralogy, and fabric make up these deposits. Microcrystalline high-magnesium calcite (14 to 19 mol% MgCO3) and aragonite are present in both semiconsolidated sediments and carbonate-cemented clasts. Aragonite occurs also as a pure phase without sediment impurities. It is formed by precipitation in cavities as botryoidal and isopachous aggregates within pure white, massive gas hydrate. Variations in oxygen isotope values of the carbonates reflect the mineralogical composition and define two end members: a Mg-calcite with δ18O =4.86‰ PDB and an aragonite with δ18O =3.68‰ PDB. On the basis of the ambient bottom-water temperature and accepted equations for oxygen isotope fractionation, we show that the aragonite phase formed in equilibrium with its pore-water environment, and that the Mg-calcite appears to have precipitated from pore fluids enriched in 18O. Oxygen isotope enrichment probably originates from hydrate water released during gas-hydrate destabilization. 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.