Regional structural trends inferred from gravity and aeromagnetic data in the New Mexico-Colorado border region
— Lindrith Cordell and G. Randy Keller

Long-term efforts to provide aeromagnetic and gravity data for the Rio Grande rift have recently led to the publication of an aeromagnetic map of New Mexico (Cordell, 1984) and gravity maps of New Mexico (Keller and Cordell, 1984) and of the Rio Grande rift covering large parts of Colorado, New Mexico, and Texas (Cordell, Keller, and Hildenbrand, 1982). These maps provide both a synoptic perspective for the study of very large structures and a readily accessible data base for New Mexico Geological Society field excursions and other topical studies. Here, we present a residual Bouguer gravity map centered on the Espanola—Taos—San Luis Basins section of the Rio Grande rift, and a corresponding aeromagnetic map for the New Mexico sector (digital data from Colorado are not yet available). Preliminary interpretations of these data suggest the presence of some remarkable structures which may record successive Laramide, Eocene, mid-Tertiary, and Neogene deformations. The maps (Figs. 1, 2) appear in the front matter of this guidebook.