Ridge segmentation, faulting and crustal thickness in the atlantic ocean

ABSTRACT THE Mid-Atlantic Ridge (MAR) between the Kane and Atlantis fracture zones consists of segments 20–85 km in length1; bull's-eye patterns in the mantle Bouguer gravity anomaly

field2 centred on several segments associated with narrow rift valleys3 have been interpreted as centres of strong mantle upwelling and thick crust. Here I present a map of normal faults

inferred from ∼5 × 104 km2of Sea Beam bathymetry4 along the MAR between 28° N and the Atlantis fracture zone. Faults are mapped both on- and off-ridge using a criterion that distinguishes

them from volcanic topography. Abyssal hill lineations seem to form at the rift valley walls through the growth of the normal faults; towards ridge segment ends these faults are more widely

spaced, with larger throws than those at segment centres, and often define the boundaries of the gravity bull's-eyes. These two different faulting styles, which probably reflect changes

in lithospheric strength, are preserved into the rift mountains. Large-throw faults are highly correlated with the mantle Bouguer highs, suggesting that amagmatic extension on the large

faults contributes to the crustal thinning inferred towards the segment ends. Access through your institution Buy or subscribe This is a preview of subscription content, access via your

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MEDITERRANEAN Article Open access 15 August 2022 PERVASIVE DETACHMENT FAULTS WITHIN THE SLOW SPREADING OCEANIC CRUST AT THE POORLY COUPLED ANTILLES SUBDUCTION ZONE Article Open access 30

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references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, 02543, USA Peter R. Shaw Authors * Peter R. Shaw View author

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faulting and crustal thickness in the Atlantic Ocean. _Nature_ 358, 490–493 (1992). https://doi.org/10.1038/358490a0 Download citation * Received: 30 March 1992 * Accepted: 19 June 1992 *

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