Heat loss and hydrothermal ciruculation due to sea-floor
spreading. Abstract (Summary)Lithospheric cooling along the
Galapagos Spreading Center at 86°W longitude, as determined by
surface heat-flow measurements, appears dominated by
hydrothermal circulation. This same phenomena apparently exists
on the Mid-Atlantic Ridge at 36°N and presumably, in some form
on all active oceanic ridges. It is responsible for removing the
majority of the heat () 80%) lost through young (few m.y. old)
oceanic crust. This component of heat has been ignored in
previous calculations of the total rate of heat loss by the
Earth. A theoretical expression is used to estimate the heat
released by sea-floor spreading, since current technology does
not provide any means for direct measurement. The revised va lue
of lO. 2 x iOl2 cal/sec (il5%) represents a 32% increase over
previous estimates. More than 20% of this heat apparently
escapes through hydrothermal vents near sea-floor spreading
centers. The previously accepted equality of ocea