HR: 11:05h
AN: T32B-03    [Abstracts]
TI: Detailed investigation of the overlapping spreading center and 9 degrees north on the East Pacific Rise: overview of the Medusa 2007 cruise activities
AU: * Klein, E M
EM: ek4@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, United States
AU: White, S
EM: swhite@geol.sc.edu
AF: Department of Geological Sciences, University of South Carolina, Columbia, SC 29208, United States
AU: Perfit, M
EM: perfit@geology.ufl.edu
AF: Dept. of Geological Sciences, University of Florida, Gainesville, FL 32611, United States
AU: Von Damm, K
EM: kvd@guero.sr.unh.edu
AF: EOS, University of New Hampshire, Durham, NH 03824, United States
AU: Fornari, D
EM: dfornari@whoi.edu
AF: Woods Hole Oceanographic Institution, MG&G, Woods Hole, MA 02543, United States
AU: Soule, A
EM: ssoule@whoi.edu
AF: Woods Hole Oceanographic Institution, MG&G, Woods Hole, MA 02543, United States
AU: Ridley, I
EM: iridley@usgs.gov
AF: USGS, Denver Federal Center, Denver, CO 80225, United States
AU: carmichael, s
EM: sarah.carmichael@unh.edu
AF: EOS, University of New Hampshire, Durham, NH 03824, United States
AU: Sims, K
EM: ksims@whoi.edu
AF: Woods Hole Oceanographic Institution, MG&G, Woods Hole, MA 02543, United States
AU: Wanless, D
EM: dorseyw@ufl.edu
AF: Dept. of Geological Sciences, University of Florida, Gainesville, FL 32611, United States
AU: Zaino, A
EM: ajz20@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, United States
AU: Fundis, A
EM: afundis@ufl.edu
AF: Dept. of Geological Sciences, University of Florida, Gainesville, FL 32611, United States
AU: Mason, J
EM: masonjl@mailbox.sc.edu
AF: Department of Geological Sciences, University of South Carolina, Columbia, SC 29208, United States
AU: O'Brien, J
EM: jobrien@geol.sc.edu
AF: Department of Geological Sciences, University of South Carolina, Columbia, SC 29208, United States
AU: Waters, C
EM: cwaters@whoi.edu
AF: Woods Hole Oceanographic Institution, MG&G, Woods Hole, MA 02543, United States
AU: Mansfield, F
AF: Caltech, Geology, Pasadena, CA 91125,
AU: Neely, K
EM: kln3@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, United States
AU: Laliberte, J
EM: jrl14@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, United States
AU: Goehring, E
EM: exg15@psu.edu
AF: Ridge 2000, Pennsylvania State University, University Park, PA 16802, United States
AU: Preston, L
EM: lpreston@salem.k12.nh.us
AF: Salem High School, 44 Geremonty Drive, Salem, NH 03079, United States
AB: We undertook a 35-day cruise on the R/V Atlantis (AT15-17; March 24 to April 27, 2007) to investigate seafloor spreading processes along the northern East Pacific Rise. The bulk of our ship time (22 science days) was devoted to studying the 9 deg 03"N overlapping spreading center (OSC). At the OSC site, we surveyed 200 sq. km. with DSL-120A (obtaining 120 kHz backscatter and phase bathymetry, 200 kHz multibeam bathymetry, magnetics, CTD, and MAPR data). This was followed by 16 days of mapping and sampling with ROV Jason II (~7000 digital photographs, recovery of ~300 rock samples, sampling of hydrothermal vent waters and biota) and with the WHOI TowCam (~10,000 digital photographs, CTD and MAPR data). We discovered one high-temperature hydrothermal vent (named "Medusa Vent" to highlight the presence of unusual pink Stauromedusae) and an associated diffuse- flow hydrothermal field (biologic samples included riftia, tevnia, alvinella). We found no evidence of widespread recent eruptions, although loci of recent volcanism were identified on each limb of the OSC. Lavas recovered ranged from basalt to dacite. The data collected will be used to explore the linkages between geochemical, geological, and hydrothermal variations on the seafloor and the subsurface magma supply system at depth. Our preliminary results suggest a complex spatial relationship between magmatism, tectonism and hydrothermal activity observed at the surface and the positions and characteristics of the magma lenses at depth.
DE: 1021 Composition of the oceanic crust
DE: 8149 Planetary tectonics (5475)
DE: 8158 Plate motions: present and recent (3040)
DE: 8178 Tectonics and magmatism
SC: Tectonophysics [T]
MN: 2007 Fall Meeting