Fluorspar deposits and the Rio Grande Rift System
— McAnulty, W. N. McAnulty, W. N.

Nearly 40 percent of the more than 200 fluorspar mines, prospects, and occurrences in New Mexico occur within or along the margins of the Rio Grande rift system. Numerous deposits occur within or marginal to the zone in Sierra, Luna and Grant counties, and there are several occurrences in Dona Ana and Socorro counties. There are a few occurrences in Bernalillo and Sandoval counties. The northern extension of the rift system into Colorado, and mineralized faults which extend further north into the Northgate fluorspar district in Colorado, constitute a trend along which numerous fluorspar mines and prospects are located. Several important fluorspar deposits occur at intervals along what some workers consider to be a southern extension of the Rio Grande rift system, a zone (Texas lineament) which extends southeasterly along the Rio Grande and the northeast side of the Coahuila tectonic belt from the vicinity of El Paso to the Sierra Madre Oriental in northern Coahuila and beyond. Thus, the question arises: What is the genetic relationship, if any, between the Rio Grande rift system per se and fluorspar deposits aligned along it?