The St. Paul Fracture Zone (FZ) in the equatorial Atlantic is interrupted by three intratransform ridge (ITR) spreading centers. A detailed magnetic survey, corrected for the diurnal variations using a moored magnetic station, six submersible dives, and three bottom-towed video camera tracks provide data on the most eastern ITR (0degrees37'N, 25degrees27'W). Visual observations and submersible sampling displayed a high ultramafic/volcanic ratio, supporting the assumption that the ITR is in a magmatically starved state. Volcanics were mainly found on the rift valley floor from 4700 to 4000 m and as a thin cap (<160 m) on the top of the eastern rift crest (2700 m). Most of the rift walls consist essentially of serpentinized peridotites and gabbros. The magnetic data show a well-defined ridge centered anomaly. A generalized inversion method was applied to the field data to calculate the crustal equivalent magnetization, assuming that the seafloor is broken down into elementary cells of 1x1x0.5 km(3) which fit the topography. The average of absolute value of equivalent magnetization is 2.7 A m(-1). The width of the central normal polarity (Brunhes epoch) is wider (at least 34 km) than that indicated by the NUVEL-1 kinematic model (24.5 km). This 40% excess is believed to be significant and is thought to be the result of prolonged chemical remanent magnetization acquired during the serpentinization of peridotites. In a magmatically starved accretion segment, we suggest that peridotites could continue to acquire magnetization as long as tectonic activities facilitate the circulation of seawater in the upper mantle.