Heat-flow anomalies crossing New Mexico along La Ristra seismic profile

Abstract

Heat-flow data along La Ristra seismic line crossing New Mexico from the Colorado Plateau to the Great Plains suggest that the Jemez Lineament and the Rio Grande rift are high heat-flow geologic provinces, which, from the heat-flow data, appear separated by a triangular wedge of Colorado Plateau. Estimated mid-depths of upper-mantle thermal sources for the Jemez Lineament and the Rio Grande rift generally agree with the mid-depths of the greatest upper-mantle seismic velocity anomalies, supporting the suggestion that these seismic anomalies are caused in part by increased temperature. Mid-depths of shallower thermal sources are near the mid-depth between the top of the crustal seismic velocity anomaly and the top of the upper-mantle seismic anomaly. Heat flow returns to intermediate values in the Colorado Plateau and the eastern rift flank of the Rio Grande rift, suggesting similar crustal and upper-mantle thermal conditions in the two regions and low values in the Great Plains, indicating cooler crustal and upper-mantle temperatures. Heat-flow values are generally consistent with seismic velocities, although differences between the data sets are observed for the Rio Grande rift eastern flank. © 2009 Geological Society of America.