HR: 1340h
AN: T33B-1351    [Abstracts]
TI: Lava Flows, Faults and Geomorphic Provinces: GIS-based Terrain Modeling at the 9N EPR Overlapping Spreading Centers
AU: * Mason, J L
EM: masonjl@mailbox.sc.edu
AF: Department of Geological Sciences, U. of South Carolina, Columbia, SC 29208, United States
AU: White, S M
EM: swhite@geol.sc.edu
AF: Department of Geological Sciences, U. of South Carolina, Columbia, SC 29208, United States
AB: How are the mounds, fissures, lava morphology and scarps we see at an overlapping spreading center related to the presence, and for that matter the depth and size, of the melt lens? Using DSL-120A, we obtained 100% side- scan (2m resolution) and 50% bathymetric (4m resolution) coverage at the 9°N OSC within an area 9 km wide between 9.18°N and 8.92°N. The 9°N OSC consists of a propagating eastern limb and a western retreating limb separated by an ~4 km wide overlap basin which is 1 km deeper than the adjacent limbs. We edited and then merged the bathymetry from the SM2000 and DSL-120A data along with EM300 and ARAD hydrosweep data to create a high-resolution bathymetry grid (<30m) covering the entire OSC. We run the NOAA Benthic Terrain Modeler on this merged bathymetry which gives us slope, roughness and shape of the terrain. We use output from the Benthic Terrain Modeler and the provinces described by Sempere and Macdonald (1986) to establish bounds on geomorphic provinces of the OSC. Geomorphic provinces each have a distinct terrain pattern. Features observed within each province from near-bottom photography and side-scan sonar are used to understand the origin of the geomorphic differences within the provinces. Photographs from the Jason 2 ROV and WHOI TowCam are analyzed and categorized by flow type (pillows, lobate, sheet, hackley and curtain flows), thickness of sediment cover and the presence of glass for each province and the whole OSC. Fissures and pillow mounds are manually digitized from DSL-120A side-scan sonar collected over the OSC. This allows us to determine how the distribution of mounds, fissures, lava morphologies and scarps differ between provinces and how changes in the location of the melt lens as well as its chemical make up and size may influence the seafloor morphology.
DE: 3035 Midocean ridge processes
DE: 3045 Seafloor morphology, geology, and geophysics
DE: 3080 Submergence instruments: ROV, AUV, submersibles
SC: Tectonophysics [T]
MN: 2007 Fall Meeting