The San Luis Valley region population is growing. Water shortfalls could have serious consequences. Future growth and land
management in the region depend on accurate assessment and protection of the region?s ground-water resources. An important
issue in managing the ground-water resources is a better understanding of the hydrogeology of the Santa Fe Group and the nature
of the sedimentary deposits that fill the Rio Grande rift, which contain the principal ground-water aquifers. The shallow
unconfined aquifer and the deeper confined Santa Fe Group aquifer in the San Luis Basin are the main sources of municipal
water for the region. The U.S. Geological Survey (USGS) is conducting a series of multidisciplinary studies of the San Luis
Basin located in southern Colorado. Detailed geologic mapping, high-resolution airborne magnetic surveys, gravity surveys,
an electromagnetic survey (called magnetotellurics, or MT), and hydrologic and lithologic data are being used to better understand
the aquifers. The MT survey primary goal is to map changes in electrical resistivity with depth that are related to differences
in rock types. These various rock types help control the properties of aquifers. This report does not include any data interpretation.
Its purpose is to release the MT data acquired at 24 stations. Two of the stations were collected near Santa Fe, New Mexico,
near deep wildcat wells. Well logs from those wells will help tie future interpretations of this data with geologic units
from the Santa Fe Group sediments to Precambrian basement.
Citation
Title Magnetotelluric Data, San Luis Valley, Colorado