An estimate of the heat flow on the meteor rise, subantarctic South Atlantic

Abstract

Heat flow determinations require more than one reliable temperature measurement to obtain an estimate of the temperature gradient, and subsequently the heat flow. Two temperature readings were taken on leg 114 of the Ocean Drilling Program, both in hole 704B on the Meteor Rise in the subantarctic South Atlantic. One of these readings appears to be reliable, but the other appears to be invalid. Because any temperature gradient and estimate of heat flow derived using these two readings will be questionable, we suggest a different approach to determine heat flow. We use the one reliable temperature measurement to calibrate the temperature derived from the induction resistivity log and the laboratory porosity measurements. The temperature and heat flow depend on the shape factor used in the modified Archie's law. The temperature gradient empirically obtained from the resistivity and porosity is 38±4 mK/m and the average heat flow is 64±8 mW/m2, which is consistent with the age of the Meteor Rise (approximately 60 to 65 Ma). These values are in agreement with the computed heat flow when we assume a simple linear temperature gradient through the sediment section.