An along axis profile of 3-D magnetic inversions for the Mid- Atlantic Ridge 31 to 35 degrees south, show low magnetization at the mid-segments and high magnetizations at the segment tips for three adjacent spreading segments. The project will measure rock magnetic properties to determine if the calculated axial magnetization low at the mid-segment, and the segment tip highs, result from thickened crust with weakly magnetized sources, average crustal thickness and magnetic strength, or normal magnetization but thinned crust. With the rock magnetic data and the finer scale 3-D inversions, the questions of to what extent the hypothesized mantle plume depress magnetization amplitudes, and are slow spreading centers near discontinuities strongly magnetized because of fractionation processes, will be addressed.