1. Heat flow and mineralogy of TAG Relict High-Temperature Hydrothermal Zones: Mid-Atlantic Ridge 26°N, 45°W
- Author
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Rona, Peter, Petersen, Sven, Becker, Keir, von Herzen, Richard, Hannington, Mark, Herzig, Peter, Naka, J., Lalou, C., Thompson, G., Petemen, Sven, Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers), Institut für Mineralogie [Freiberg], Technishe Universität Bergakademie Freiberg (TU Bergakademie Freiberg), Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables], Woods Hole Oceanographic Institution (WHOI), Geological Survey of Canada [Ottawa] (GSC Central & Northern Canada), Geological Survey of Canada - Office (GSC), Natural Resources Canada (NRCan)-Natural Resources Canada (NRCan), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Centre des Faibles Radioactivités, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,geography ,geography.geographical_feature_category ,Volcanogenic massive sulfide ore deposit ,Mineralogy ,Mid-ocean ridge ,Mid-Atlantic Ridge ,engineering.material ,Hydrothermal circulation ,Geophysics ,Volcano ,Phanerozoic ,engineering ,General Earth and Planetary Sciences ,Paragenesis ,Pyrite ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,Geology - Abstract
International audience; Submersible investigations employing heat flow measurements (12 stations), sampling and imagery of the two relict high-temperature hydrothermal zones of the TAG field, the Alvin and Mir sulfide zones, elucidate relations between heat sources and mineralization including an active sulfide mound that has been the focus of prior studies. Values of heat flow in the Mir zone and at the margin of the active mound are inversely proportional to distance from adjacent volcanic centers. This observation supports the hypothesis that intrusions at volcanic centers adjacent to the high-temperature hydrothermal zones supply the heat to drive hydrothermal activity. The chronology of hydrothermal deposits in the different zones indicates that the intrusions are episodic with field-wide high-temperature hydrothermal events recurring at intervals of tens of thousands of years, while activity at individual zones may recur at intervals of hundreds to thousands of years. A sequence of hydrothermal deposits ranges to at least 140,000 years ago from massive sulfides forming at the active mound, to recrystallization of sulfides in the active and relict zones, to pyritization of an inactive mound in the Alvin zone; low-temperature mineral phases precipitate before, during and after the sulfides. a 5 x 5 km area of the floor and wall on the east side of the rift valley near the center of a spreading segment of the Mid-Atlantic Ridge near 26øN, 45øW (Fig. 1; Rona et al., 1993). A microearthquake survey of the TAG segment indicated that the
- Published
- 1996
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