Ridge segmentation, faulting and crustal thickness in the Atlantic Ocean

摘要: THE Mid-Atlantic Ridge (MAR) between the Kane and Atlantis fracture zones consists of segments 20–85 km in length1; bull's-eye patterns mantle Bouguer gravity anomaly field2 centred on several associated with narrow rift valleys3 have been interpreted as centres strong upwelling thick crust. Here I present a map normal faults inferred from ∼5 × 104 km2of Sea Beam bathymetry4 along MAR 28° N zone. Faults are mapped both on- off-ridge using criterion that distinguishes them volcanic topography. Abyssal hill lineations seem to form at valley walls through growth faults; towards ridge segment ends these more widely spaced, larger throws than those centres, often define boundaries bull's-eyes. These two different faulting styles, which probably reflect changes lithospheric strength, preserved into mountains. Large-throw highly correlated highs, suggesting amagmatic extension large contributes crustal thinning ends.