Heat transfer through the sediments of the mounds hydrothermal area, Galapagos Spreading Center at 86oW.

Heat transfer processes at the mounds area of the Galapagos Spreading Center at 86oW are revealed by temperatures measured at approx 10m intervals in the 30+ or -10m sediment at each of 12 holes at DSDP Leg 70 Sites 506-509 and by temperatures of up to five thermistors on eleven 8-12m long piston cores. The 325 needle- probe values show a significant linear increase of thermal conductivity with depth in each core. About half of the temperature-thermal resistance profiles are nonlinear and are fit to a steady state, vertical pore water advection model. Results indicate high and variable total heat flow and localized hydrothermal discharge at approx 10^-8m/s, associated with individual mounts. Recharge is indicated at similar rates in the low heat flow belt approx 5km S of the mounds and is suggested at slower rates in the intermediate heat flow (0.17-0.42 W/m²) belt surrounding the mounds heat flow high. Possible slow entrained recharge within approx 100m of discharging mounds is suggested.-Authors