Preliminary Map of Temperature Gradients in the Conterminous United States

Abstract

Temperature gradients have been determined from temperature/depth measurements made in drill holes deeper than 600 m and used in construction of a temperature gradient map of the conterminous United States. The map displays temperature gradients that can be expected to exist regionally in a conductive thermal regime to a depth of 2 km. The major difference between this map and the AAPG-USGS temperature gradient map is in the midcontinental region where the AAPG-USGS map does not demarcate a division between colder eastern and warmer western thermal regimes. A comparison with the heat flow map of Saas et al indicates that temperature gradients commonly reflect regional heat flow, and the gross east-west division of the United States on the basis of heat flow is also expressed by temperature gradients.