Heat transfer through the sediments of the mounds hydrothermal area, Galapagos Spreading Center at 86 /sup 0/W

Journal Article · Thu Feb 10 04:00:00 EST 1983 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB088iB02p00995· OSTI ID:6250127

Becker, K; Von Herzen, R P

Heat transfer processes at the mounds area of the Galapagos Spreading Center at 86 /sup 0/W are revealed by temperatures measured at roughly-equal10-m intervals in the 30 +- 10 m sediment at each of 12 holes at DSDP Leg 70 Sites 506--509 and by temperatures of up to five thermistors on eleven 8--12 m 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 roughly-equal10/sup -8/ m/s, associated with individual mounds. Recharge is indicated at similar rates in the low heat flow belt roughly-equal5 km south of the mounds and is suggested at slower rates in the intermediate heat flow (0.17--0.42 W/m/sup 2/) belt surrounding the mounds heat flow high. Possible slow entrained recharge within roughly-equal100 m of discharging mounds is suggested. Also suggested is strong local discharge along the major fault bounding the mounds crustal block to the north. About 95 km north of the spreading axis, at DSDP Site 510, temperatures in the 114-m sediment cover on 2.7-m.y. crust are linear, consistent with the suggestion that the hydraulic resistance of this layer is sufficient to seal off free hydrothermal exchange between basement and bottom water. The combination of heat flow data and the physical properties data of Karato and Becker (this issue) suggests that roughly-equal50 m of sediment may be a threshold thickness for sealing of hydrothermal circulation within basement, where the topography is smooth. We suggest that the formation of mounds may be associated with the forced localization of hydrothermal discharge through the sediment, as its thickness approaches this threshold value.

• Research Organization: University of California, San Diego, Marine Physical Laboratory, Scripps Institution of Oceanography, La Jolla, California 92093
• OSTI ID: 6250127
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 88:B2; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580500* -- Oceanography-- (1980-1989)
EARTH CRUST
ENERGY SYSTEMS
ENERGY TRANSFER
GEOTHERMAL GRADIENTS
GEOTHERMAL SYSTEMS
GEOTHERMOMETRY
HEAT TRANSFER
HYDROTHERMAL SYSTEMS
OCEANIC CRUST
PACIFIC OCEAN
PHYSICAL PROPERTIES
SEA-FLOOR SPREADING
SEAS
SEDIMENTS
SURFACE WATERS
TEMPERATURE GRADIENTS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES