HR: 1340h
AN: T33D-0589    [Abstracts]
TI: DSL120 Mosaics of Superfast EPR Crustal Layers Exposed by Ultraslow Spreading near Pito Deep
AU: * Naar, D F
EM: naar@usf.edu
AF: University of South Florida, College of Marine Science 140 Seventh Avenue South, St. Petersburg, FL 33701-5016 United States
AU: Hey, R N
EM: hey@soest.hawaii.edu
AF: University of Hawaii, HIGP/SOEST 2525 Correa Road, Honolulu, HI 96822 United States
AU: Gee, J S
EM: jsgee@ucsd.edu
AF: University of California, S.D., GRD/SIO , La Jolla, CA 92092-0220 United States
AU: Hekinian, R
EM: hekinian.roger@wanadoo.fr
AF: Keryunan, St. Renan, Plouzane, BRE 29290 France
AU: Francheteau, J
EM: jean.francheteau@univ-brest.fr
AF: University of Bretagne Occidentale, Inst Univ Europeen de la Mer, Plouzane, BRE 29280 France
AU: Karson, J A
EM: jkarson@duke.edu
AF: Duke University, Div of Ocean and Earth 103 Old Chemistry Bldg, Durham, NC 27708-0230 United States
AU: Klein, E M
EM: ek4@duke.edu
AF: Duke University, Div of Ocean and Earth 103 Old Chemistry Bldg, Durham, NC 27708-0230 United States
AU: Gillis, K M
EM: kgillis@uvic.ca
AF: University of Victoria, School of Ocean and Earth Sciences PO BOX 3055, Victoria, BC V8T3P6 Canada
AU: Varga, R J
EM: rvarga@wooster.edu
AF: The College of Wooster, Dept of Geology, Wooster, OH 44691 United States
AU: Party, P S
T33D-0589 AF: Various Universities, Various Streets, St. Petersburg, FL 33701 United States
AB: WHOI DSL-120 (120 kHz deep-towed) side-scan sonar data were collected in two study areas in an attempt to identify outcrops of exposed layers of superfast oceanic crust for detailed studies using submersible Alvin and ROV Jason-II. Each area is several kilometers long and span a depth range of about 1500 m. These areas represent southwest dipping normal faults on the Nazca plate side of Pito Deep, which is about 400 km to the northwest of Easter Island in the Southeast Pacific. The ~6 km Deep was formed by ultraslow seafloor spreading (~10 mm/yr) associated with a nearby pole of rotation of the northwestward propagating Pito Rift. The propagation and ultraslow seafloor spreading has primarily resulted in the formation of several major normal faults that have exposed superfast crustal layers. Direct observations, imaging, and sampling (using Alvin and Jason-II) along with earlier Nautile dive observations are used to interpret the side-scan sonar records. As described in a companion abstract, four major rock units were mapped: a pelagic sedimentary layer, basaltic layer, a sheeted diabase dike layer, and a gabbroic layer. The overall distribution of these layers and the transitions between the layers, their estimated thickness, continuity, and localized zones of faulting and deformation, will be summarized in a final interpretation map.
UR: http://www.nicholas.duke.edu/pitodeep/index.html
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3035 Midocean ridge processes
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 3075 Submarine tectonics and volcanism
DE: 8416 Mid-oceanic ridge processes (1032, 3614)
SC: Tectonophysics [T]
MN: Fall Meeting 2005