Applied Tectonic Geomorphology to Geothermal Exploration in the Tularosa Basin, New Mexico

Abstract

The Tularosa Basin in south-central New Mexico has been undergoing extensional deformation for the past ~30 million years, inducing large-scale basin-bounding normal faulting. The structural geology of this region is similar to the rest of the Basin and Range, and so in determining structural favorability for hosting a hidden geothermal systems it is useful to compare this area with known geothermal resource areas. Specifically, this paper details tectonic geomorphology analysis of alluvial fans within the study area which are then compared with that of Dixie Valley, Nevada, arguably the most prolific geothermal system in the Basin and Range. The Rio Grande Rift, which defines the western boundary of the study area, is presently extending at a rate of ~0.5mm/yr, with a considerable amount of local variability. To facilitate this study, 10 m DEM data was integrated into a Geographic Information System (GIS) and used to analyze alluvial fan geomorphometry and quaternary faulting within the proximity of geothermal plays identified in Phase I of the Tularosa Basin Play Fairway Modelling research project funded by the DOE. The morphology of alluvial fans is directly associated with base level drops triggered by basin-bounding normal fault offset. By classifying fault segments as having relatively younger and more frequent seismic activity, conclusions about subsurface permeability can be made which provides critical information about the potential for a productive geothermal system which will improve the play fairway model.