HR: 1340h
AN: OS43A-0993    [Abstracts]
TI: Geochemical Characterization of Hydrothermal Plume Fluids From Peridotite- and Basalt- Dominated Regions of the Ultra-Slow Spreading Gakkel Ridge
AU: * Upchurch, L
EM: upchurch@utmsi.utexas.edu
AF: University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78373, United States
AU: Edmonds, H N
EM: edmonds@utmsi.utexas.edu
AF: University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78373, United States
AU: Resing, J
EM: joseph.resing@noaa.gov
AF: NOAA/PMEL, 7600 Sand Point Way NE, Building 3, Seattle, WA 98115, United States
AU: Nakamura, K
EM: koichi.nakamura@aist.go.jp
AF: National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, 305-8567, Japan
AU: Buck, N
EM: nathan.buck@noaa.gov
AF: NOAA/PMEL, 7600 Sand Point Way NE, Building 3, Seattle, WA 98115, United States
AU: Liljebladh, B
EM: beli@oce.gu.se
AF: Goteborg University, Dept Earth Sciences, Box 460, Goteborg, 40530, Sweden
AU: Stranne, C
EM: stranne@gvc.gu.se
AF: Goteborg University, Dept Earth Sciences, Box 460, Goteborg, 40530, Sweden
AU: Tupper, G
EM: gtupper@whoi.edu
AF: Woods Hole Ocenaographic Institution, 360 Woods Hole Rd, Woods Hole, MA 02543, United States
AU: Winsor, P
EM: pwinsor@whoi.edu
AF: Woods Hole Ocenaographic Institution, 360 Woods Hole Rd, Woods Hole, MA 02543, United States
AB: Geochemical characterization of hydrothermal plumes initially located during the 2001 AMORE cruise to the Gakkel Ridge was undertaken as part of the 2007 Arctic Gakkel Vents Expedition (AGAVE). One peridotite- and one basalt-dominated area were targeted for this exploration to constrain the range of venting environments found on the Gakkel Ridge, the ultra-slow spreading endmember of the global mid-ocean ridge. CTD hydrocasts at the 7 E peridotite-hosted site relocated the plumes found initially on the AMORE cruise. The target plume was located between 2800 and 2950 meters and exhibited a localized signal in temperature and light scattering. While shipboard analysis of dissolved gases was unavailable at the 7 E site, samples were preserved for manganese and helium measurements. No Eh signal was found at the 7 E site. The 85 E basalt-hosted site has experienced recent volcanic activity and was more extensively studied relative to the 7 E site during the AGAVE cruise. CTD casts detected numerous temperature, light scattering, and Eh plumes at 85 E indicative of multiple hydrothermal sources. Three of the plumes sampled exhibited methane concentrations ranging from 20 nM to greater than 250 nM and hydrogen concentrations ranging from 10nM to 100nM. In situ Eh measurements recorded negative excursions of at least 25 mV in each plume. Associated manganese and particle chemistry samples collected at both sites will be analyzed in time for this meeting.
DE: 1034 Hydrothermal systems (0450, 3017, 3616, 4832, 8135, 8424)
DE: 1065 Major and trace element geochemistry
DE: 4207 Arctic and Antarctic oceanography (9310, 9315)
DE: 4808 Chemical tracers
DE: 4825 Geochemistry
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting