HR: 1330h
AN: T32A-0912    [PDF]
TI: Complexities of Eruptive Processes at Mariana Forearc Serpentinite Mud Volcanoes and Implications for Serpentinite M\'{e}lange Development
AU: * Fryer, P
EM: pfryer@hawaii.edu
AF: SOEST/University of Hawaii, 1680 East West Rd, Honolulu, HI 96822 United States
AU: Becker, N C
EM: nbecker@hawaii.edu
AF: SOEST/University of Hawaii, 1680 East West Rd, Honolulu, HI 96822 United States
AU: Wheat, C G
EM: wheat@mbari.org
AF: University of Alaska, Fairbanks, PO Box 757220, Fairbanks, AK 99775 United States
AU: Hulme, S
EM: shulme@nsf.mlml.calstate.edu
AF: Moss Landing Marine Lab, 8272 Moss Landing Rd, Moss Landing, CA 95039 United States
AU: Fryer, G J
EM: gerard@hawaii.edu
AF: SOEST/University of Hawaii, 1680 East West Rd, Honolulu, HI 96822 United States
AU: Gharib, J
EM: gharib@hawaii.edu
AF: SOEST/University of Hawaii, 1680 East West Rd, Honolulu, HI 96822 United States
AU: Mottl, M J
EM: mmottl@soest.hawaii.edu
AF: SOEST/University of Hawaii, 1000 Pope Rd, Honolulu, HI 96822 United States
AB: Detailed DSL120 side-scan sonar surveys and Jason2/Medea ROV observations of the summit areas of several serpentinite mud volcanoes on the eastern half of the Mariana forearc reveal vent dimensions and information about the size and dynamics of mud protrusions emanating from the vents. Some vents appear to be small (a few km in diameter), which suggests narrow conduits beneath the mud volcanoes. Other sites of mud flow emanation appear to be along fissures a few tens to hundreds of m long. New high-resolution bathymetry of the seamounts shows details of the seamount flanks that confirm multiple lobes of mud protrusions and show evidence of catastrophic collapse events, possibly associated with pulses of larger-volume fluid egress. The collapse events scour channels in the sides of the edifices and in some instances distribute large volumes of material about the base of the seamounts. The debris shed from the edifices can extend for tens of kilometers outward from the flanks of the edifices. The seamounts are clearly subject to large-scale episodic disruption. Some bear fault traces throughout the edifices. Shallow earthquake activity in the Mariana forearc is largely confined to the outer 100-km zone of faulting and serpentinite seamount formation. Fault zones in the outer forearc control canyons that probably channel debris from the seamounts toward the trench axis. The wide-spread distribution and reworking of debris shed from the mud volcano edifices and from fault-exposed serpentinite provides a model for the formation of complex serpentinite m\'{e}lange deposits in exotic terranes, such as the Franciscan of California.
DE: 0933 Remote sensing
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 3045 Seafloor morphology and bottom photography
DE: 7218 Lithosphere and upper mantle
DE: 8015 Local crustal structure
SC: Tectonophysics [T]
MN: 2003 Fall Meeting