Geothermal Gradient Map of the United States (Exclusive of Alaska and Hawaii)

Abstract

This paper describes an update of the Geothermal Gradient Map of the Conterminous United States (Kron and Heiken 1980) and compares the changes made since the first map. The second map presents a compilation of over 1700 wells that have been measured for temperature below 50 m and whose temperature/depth profiles are linear, or composed of linear segments which reflect changes in the thermal conductivity of the rocks rather than hydrology. The data are displayed at an enlarged scale of 1:2,500,000 and in a new format which shows the location, depth, and gradient of each well in a single color coded symbol. This edition contains over two times the amount of data shown on the first map and is accompanied by a table, listing for each well its location, depth, gradient, heat flow (where available), thermal conductivity (where available) and a reference. Over 200 references have been consulted and are presented with the data.