HR: 0800h
AN: OS51A-0553    [Abstracts]
TI: The South Pacific Bare Zone
AU: * Paul, C F
EM: farralon@gmail.com
AF: Center for the Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID 83725-1536
AU: Lyle, M W
EM: mlyle@cgiss.boisestate.edu
AF: Center for the Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID 83725-1536
AU: Rea, D K
OS51A-0553 AF: Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005
AU: Liberty, L M
OS51A-0553 AF: Center for the Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID 83725-1536
AU: Hovan, S A
OS51A-0553 AF: Department of Geoscience, Indiana University of Pennsylvania, Indiana, PA 15705-1087
AU: Gleason, J D
OS51A-0553 AF: Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005
AU: Hendy, I L
OS51A-0553 AF: Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005
AU: Latimer, J C
OS51A-0553 AF: Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005
AU: Owen, R M
OS51A-0553 AF: Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005
AU: Thomas, D J
OS51A-0553 AF: Department of Oceanography, Texas A & M University, College Station, TX 77843-3146
AU: Murphy, B M
OS51A-0553 AF: Center for the Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID 83725-1536
AU: Stancin, A M
OS51A-0553 AF: Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005
AU: Bolyn, M P
OS51A-0553 AF: Department of Geoscience, Indiana University of Pennsylvania, Indiana, PA 15705-1087
AB: The South Pacific is relatively unexplored and is almost devoid of digitally-acquired seismic reflection data. While surveying for an IODP cruise on R/V Melville in February-March 2005, we identified a region of zero sediment accumulation nearly two million square kilometers in area in the Southwest Pacific Basin. This South Pacific Bare Zone is bounded approximately between the Menard Fracture Zone and the Austral Islands, or 45 and 30 degrees South latitude, and between the Adventure Trough and the Pandora Trough, or roughly 130 and 142 degrees West longitude. Seismic profiles were acquired throughout the region via 3.5 kHz echo sounder and 150 cu. in. GI airgun. This 55 million year hiatus in sedimentation marks the slowest known accumulation of sediment anywhere in the world. There is no evidence for erosion within the Bare Zone. For example, we do not typically observe sediment in basins or asymmetric sediment piles along the margins of the zone. Furthermore, the overall size of the bare region is simply too large for erosion to account for the lack of sediment. Contributing factors for low marine sedimentation rates include low biological productivity, shallow CCD/deep crustal subsidence, minimal terrigenous input, and low input of hydrogenous/hydrothermal oxides. All of these conditions coincide within the boundaries of the South Pacific Bare Zone.
DE: 3045 Seafloor morphology, geology, and geophysics
DE: 3099 General or miscellaneous
DE: 4223 Descriptive and regional oceanography
DE: 4273 Physical and biogeochemical interactions
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005