Geothermal Regime in the Central and Eastern United States East of the Rocky Mountains

Abstract

The thermal regime in the United States in the area of to 49" latitude and to 115" latitude and east of the Rocky Mountains has been investigated and characterized by developing and integrating several digital data bases. Data sets for heat flow, surface temperature, sedimentary rock thickness, mean thermal conductivity of the sedimentary section, and mean geothermal gradient of the sedimentary section have been developed at a resolution of 5' of latitude and longitude (about 4 to 5 km ). The advantages of the data bases are in the flexibility and adaptability to use in study of a variety of scenarios of geothermal resource evaluation and development. The design temperatures and depths for exploitation of a HDR resource, for example, can be varied, and potential calculated for a variety of different assumptions. As an example of the use of these data sets a temperature map for a depth of 4 km is illustrated. At the scale of study temperatures range from less than 60?C to over 150?C at 4 km. The temperature is between 70 and 110?C for about 82% of the area. There are significant areas with temperatures of 130?C and above. The results demonstrate the application of the data bases to geothermal resource evaluation, as well as the existence of high temperature areas at depth in the central and eastern United States that are worthy of further individual study.