Block-tilting, transfer faults, and structural control of magmatic and hydrothermal processesin the TAG area, Mid-Atlantic Ridge 26°N

Research Article| December 01, 1990 Block-tilting, transfer faults, and structural control of magmatic and hydrothermal processesin the TAG area, Mid-Atlantic Ridge 26°N JEFFREY A. KARSON; JEFFREY A. KARSON 1Department of Geology, Duke University, Durham, North Carolina 27706 Search for other works by this author on: GSW Google Scholar PETER A. RONA PETER A. RONA 2National Oceanographic and Atmospheric Administration, Atlantic Oceanographic and Meterological Laboratory, Miami, Florida 33149 Search for other works by this author on: GSW Google Scholar Author and Article Information JEFFREY A. KARSON 1Department of Geology, Duke University, Durham, North Carolina 27706 PETER A. RONA 2National Oceanographic and Atmospheric Administration, Atlantic Oceanographic and Meterological Laboratory, Miami, Florida 33149 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1990) 102 (12): 1635–1645. https://doi.org/10.1130/0016-7606(1990)102<1635:BTTFAS>2.3.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 JEFFREY A. KARSON, PETER A. RONA; Block-tilting, transfer faults, and structural control of magmatic and hydrothermal processesin the TAG area, Mid-Atlantic Ridge 26°N. GSA Bulletin 1990;; 102 (12): 1635–1645. doi: https://doi.org/10.1130/0016-7606(1990)102<1635:BTTFAS>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 SocietyGSA Bulletin Search Advanced Search Abstract Seven Alvin dives (14 km total) and numerous deep-towed camera traverses using ANGUS and NOAA camera systems provide dense coverage of a 12-km2 portion of the eastern wall of the Mid-Atlantic Ridge in the TAG area (26°N lat.). These data, in conjunction with recent Soviet Mir submersible data, provide important constraints on the tectonic, magmatic, and hydrothermal history of this spreading center segment. Active hydrothermal venting occurs near the junction of the median valley floor and eastern median valley wall and appears to be tectonically controlled by the intersection of major fault zones. An east-west fault-line scarp interpreted as an accommodation zone intersects escarpments associated with 020°-trending (ridge-parallel) normal faults that bound the median valley floor. The accommodation zone permits differential extension and rotation between major crustal blocks to the north and south. On the basis of the distribution of tilted chalk beds and geochemical anomalies in sediments, this fault zone has been intermittently active for at least 5x104 yr. The accommodation zone has apparently provided a conduit of high permeability oriented at a high angle to the ridge axis. Observations and samples from areas surrounding active and inactive vent sites provide evidence for three distinct episodes for hydrothermal outflow driven by separate magmatic events. The geometry of this active system may have implications for the location of hydrothermal systems in active spreading regimes and for massive sulfide exploration in ophiolite terranes. 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.