Active hydrothermal vents and sulfide deposits on the southern Juan de Fuca Ridge

Research Article| March 01, 1983 Active hydrothermal vents and sulfide deposits on the southern Juan de Fuca Ridge William R. Normark; William R. Normark 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Janet L. Morton; Janet L. Morton 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Randolph A. Koski; Randolph A. Koski 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar David A. Clague; David A. Clague 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar John R. Delaney John R. Delaney 2Department of Oceanography, University of Washington, Seattle, Washington 98195 Search for other works by this author on: GSW Google Scholar Author and Article Information William R. Normark 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Janet L. Morton 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Randolph A. Koski 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 David A. Clague 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 John R. Delaney 2Department of Oceanography, University of Washington, Seattle, Washington 98195 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1983) 11 (3): 158–163. https://doi.org/10.1130/0091-7613(1983)11<158:AHVASD>2.0.CO;2 Article history First Online: 01 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 William R. Normark, Janet L. Morton, Randolph A. Koski, David A. Clague, John R. Delaney; Active hydrothermal vents and sulfide deposits on the southern Juan de Fuca Ridge. Geology 1983;; 11 (3): 158–163. doi: https://doi.org/10.1130/0091-7613(1983)11<158:AHVASD>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 Massive-sulfide deposits rich in zinc and silver were recovered from the Juan de Fuca Ridge 500 km west of Oregon in September 1981. The samples recovered are composed largely of zinc sulfide, with lesser amounts of iron, lead, and copper sulfide. Most of the deposits occur at a series of hydrothermal vents within a relatively continuous depression in the center of a smooth 1-km-wide valley along the ridge axis. The depression appears to be formed by collapse of a lava lake possibly modified by extensional faulting. The axial valley floor outside the depression is underlain by fresh, glassy, ferrobasalt sheet and lobate flows. Two types of sulfide-mineral deposits were dredged from one of the hydrothermal vents: (1) angular slabs of dark-gray zinc sulfide; and (2) subrounded fragments of porous light-gray zinc sulfide. The samples contain fresh sphalerite, zoned wurtzite, pyrite, and minor amounts of marcasite, galena, and chalcopyrite-cubanite. The spreading rate of the Juan de Fuca Ridge and the composition of the sulfide samples are generally similar to the East Pacific Rise lat 21° N site; however, the texture and geologic setting of the sulfide deposits are significantly different. 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.