Geothermal characteristics of the colorado plateau

Abstract

New heat-flow measurements in the Colorado Plateau varying in depth from 400 to 1900 m suggest that the heat flux throughout the region is 1.5 HFU and greater (1 HFU = 41.8 mW/m2). Along the eastern and southern boundaries of the Plateau, near the San Juan volcanic field and the Mogollon Slope respectively, high heat flows ($2.2 HFU) are observed to intrude 50–100 km into the Plateau. It is believed that the high heat flows are associated with the sources of the volcanics in those areas. In the interior areas of the Plateau, away from the major volcanic phenomena along its boundary (e.g., the Black Mesa—Kaiparowits synclinorium, the Four Corners area, and the Piceance and Uinta basins) heat flows are generally between 1.5 and 1.8 HFU, and appear to be rather uniform over large areas. This uniform heat-flow characteristic over large areas of the interior Plateau suggests the lack of large-scale, widespread, crustal thermal sources as in the Basin and Range or along the Rio Grande rift. It is possible that lithospheric temperatures within the Colorado Plateau were once similar to lithospheric temperatures within the Stable Interior. Present heat-flow differences between the two provinces (~0.4 HFU) may define the temperature change occurring in the lithosphere of the Colorado Plateau over the past 200 m.y. This temperature change may have contributed significantly to the uplifting of the Colorado Plateau by the process of thermal expansion.