Subsurface tectonic structure between overlapping mid-ocean ridge segments

Citation:
Tong, CH, Lana C, White RS, Warner MR, Barton PJ, Bazin S, Harding AJ, Hobbs RW, Kent GM, Orcutt JA, Pye JW, Singh SC, Sinha MC.  2005.  Subsurface tectonic structure between overlapping mid-ocean ridge segments. Geology. 33:409-412.

Keywords:

18, Solid-earth geophysics, anisotropy, cracks, crust, East Pacific, East Pacific Rise, faults, lineaments, lithosphere, melts, mid-ocean ridges, oceanic crust, oceanic lithosphere, Pacific Ocean, plate tectonics, sea-floor, segmentation, spreading, spreading centers, tectonic elements, tectonics, traveltime residuals, velocity structure

Abstract:

Our results from seismic anisotropy analyses reveal for the first time the complex spatial variability of the characteristics of subsurface tectonic structures associated with ridge propagation. The significance lies in the fact that these variations are found at a locality with few lineaments or fissures at seafloor level. The overlap region between mid-ocean ridge segments at 9 degrees N on the East Pacific Rise is characterized by aligned cracks that are structurally more closely related to the propagating-ridge segment. These aligned cracks, which are approximately parallel to the ridge segments, provide conclusive observational evidence for establishing the nontransform nature of overlapping spreading centers, especially those with overlap basins covered by volcanic edifices. The aligned cracks of the 9 degrees 03'N overlapping spreading center are more similar to the ridge-parallel lineaments observed between overlapping axial-summit collapse troughs than those found at larger overlapping spreading centers. Our results therefore suggest that the lithospheric deformation between overlapping ridge segments depends on ridge offset and that this dependency may be thermally related.

Notes:

n/a

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DOI:

10.1130/g21245.1