Figure F6. Depth to axial low-velocity zone plotted against spreading rate, modified from Purdy et al. (1992) and Carbotte et al. (1997). Depth vs. rate predictions from two models of Phipps Morgan and Chen (1993) are shown, extrapolated subjectively to 200 mm/yr (dashed lines). Penetration to date in Holes 504B and 1256D is shown by solid vertical lines. MAR = Mid-Atlantic Ridge, EPR = East Pacific Rise, JdF = Juan de Fuca Ridge, Lau = Valu Fa Ridge in Lau Basin, CRR = Costa Rica Rift.

Figure F6. Depth to axial low-velocity zone plotted against spreading rate, modified from Purdy et al. (1992) and Carbotte et al. (1997). Depth vs. rate predictions from two models of Phipps Morgan and Chen (1993) are shown, extrapolated subjectively to 200 mm/yr (dashed lines). Penetration to date in Holes 504B and 1256D is shown by solid vertical lines. MAR = Mid-Atlantic Ridge, EPR = East Pacific Rise, JdF = Juan de Fuca Ridge, Lau = Valu Fa Ridge in Lau Basin, CRR = Costa Rica Rift.