FUJI Dome: A large detachment fault near 64 degrees E on the very slow-spreading southwest Indian Ridge
| Type | Article | ||||||||
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| Date | 2003-08-08 | ||||||||
| Language | English | ||||||||
| Author(s) | Searle Rc1, Cannat M2, Fujioka K3, Mevel C2, Fujimoto H4, Bralee A1, Parson L5 | ||||||||
| Affiliation(s) | 1 : Univ Durham, Dept Geol Sci, Durham DH1 3LE, England. 2 : Inst Phys Globe, CNRS, Lab Geosci Marines, F-75252 Paris, France. 3 : Japan Marine Sci & Technol Ctr, Yokosuka, Kanagawa 2370061, Japan. 4 : Tohoku Univ, Fac Sci, Res Ctr Predict Earthquakes & Volcan Erupt, Aoba Ku, Sendai, Miyagi 9808578, Japan. 5 : Southampton Oceanog Ctr, Southampton SO14 3ZH, Hants, England. |
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| Source | Geochemistry Geophysics Geosystems (1525-2027) (Amer Geophysical Union), 2003-08-08 , Vol. 4 , N. 8 , P. 1-25 | ||||||||
| DOI | 10.1029/2003GC000519 | ||||||||
| WOS© Times Cited | 63 | ||||||||
| Keyword(s) | Southwest Indian Ridge, detachment, submersible, magnetic, gravity, marine geology and geophysics : midocean ridge processes, marine geology and geophysics :, seafloor morphology and bottom photography | ||||||||
| Abstract | 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 10degrees- 20degrees, but near the breakaway it is strongly rotated outward, and dips away from the axis at up to 40degrees. 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. | ||||||||
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