Searle, R. C. and Cannat, M. and Fujioka, K. and Mevel, C. and Fujimoto, H. and Bralee, A. and Parson, L. (2003) 'FUJI Dome : a large detachment fault near 64°E on the very slow-spreading southwest Indian Ridge.', Geochemistry, geophysics, geosystems., 4 (8). p. 9105.
A continuous, domed detachment surface (FUJI Dome) has been imaged on the very slow-spreading southwest Indian Ridge using deep-towed side-scan sonar, and has been investigated by manned submersible and sea-surface geophysics. The Dome is morphologically similar to other oceanic detachments, core complexes or mega-mullions. In addition to bathymetric mullions observed in ship-borne bathymetry, finer scale spreading-parallel striations were imaged with the side scan. On the detachment surface, metabasalt crops out near the termination, probably as part of a thin fault sliver. Gabbro and troctolite probably crop out near the summit of the dome. The rest of the detachment surface is covered with sediment and rubble which is basaltic except for a single sample of serpentinite. Most of the detachment surface dips toward the ridge axis at 10°–20°, but near the breakaway it is strongly rotated outward, and dips away from the axis at up to 40°. Normal, undeformed volcanic seafloor crops out adjacent to the detachment. Modeling of sea surface magnetic data suggest the detachment was active from 1.95 Ma for about 1 Ma during a period of reduced and asymmetric magmatic accretion. Modeling of sea surface and seafloor gravity requires laterally fairly uniform but high density material under the Dome, and precludes steeply dipping contacts between bodies with large density contrasts at shallow levels under the Dome.
|Keywords:||Midocean ridge processes, Seafloor morphology and bottom photography.|
|Full text:||PDF - Published Version (1120Kb)|
|Publisher Web site:||http://dx.doi.org/10.1029/2003GC000519|
|Publisher statement:||© 2003 American Geophysical Union. Searle, R. C. and Cannat, M. and Fujioka, K. and Mevel, C. and Fujimoto, H. and Bralee, A. and Parson, L., (2003), ‘FUJI Dome : a large detachment fault near 64°E on the very slowspreading southwest Indian Ridge.’, Geochemistry, geophysics, geosystems., 4 (8). Article 9105, 10.1029/2003GC000519 (DOI). To view the published open abstract, go to http://dx.doi.org and enter the DOI.|
|Record Created:||06 Oct 2008|
|Last Modified:||11 Aug 2011 16:52|
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