Geothermal measurements at Deep Sea Drilling Project Site 587 ( Leg 90, Pacific).

Abstract

A new WHOI heat flow instrument was successfully used to obtain temperature-time records for 3 depths at DSDP Site 587. In order to arrive at an estimate for in situ, steady-state temperature, these data are applied to a 2-D theoretical formulation that describes the cooling behavior of an annular cylinder surrounded by sediment. An average heat flow of 56.9mW/m2 is computed from the resulting temperature profile. This value is in close agreement with the theoretical heat flux of 53.0mW m2 determined from the general heat flow-age relationship. The temperature profile at Site 587 is nonlinear. Examination of the effects of sudden changes in bottom water temperature and upward movement of pore fluid fails to provide convincing solutions to the cause of this nonlinearity. Knowing sediment permeability and extending the theoretical data analysis to 3-D would improve understanding of the geothermal environment at this location.-from Authors