FIGURE 5. Results for stretching-dominated ridge models.

Two model cases are shown in a and b for different values of M, but with the same lithospheric structure. a, Note the fairly symmetric axial valley and the moderate fault offsets for M = 0.95 which matches the sense of the bathymetric profile from the 115° E segment of the Southeast Indian Ridge (from Fig. 1b). Reducing the model lithospheric thickness by about one-third produces a better fit to this bathymetry. b, Faults with very large offset occur for M = 0.5. The model topographic profile is similar to that observed near the intersection of the Mid-Atlantic Ridge and the Kane transform (from Fig. 1c). The model is consistent with the large offset faults seen at the inside corners of such slow-spreading segments, as well as with the asymmetry in magmatic accretion, because most magmatic accretion takes place on the side of the ridge with smaller fault offsets.