This province extends from the Mexico/United States border between Sasabe in the east, through Nogales and Agua Prieta (Sonora), to the vicinity of Estacion Palomas (Chihuahua). Geographically, the metallogenic province coincides with the Sierra Madre Occidental Physiographic Province of Raisz (1959); on the west it is limited by the contact of the Gulf of California/Pacific Coastal Plains and on the east with the westernmost central Chihuahua valleys (Fig. 1). Over an area of almost 275,280 km2, its axis runs northwest-southeast from the American border to the city of Guadalajara (Jalisco).
The Sierra Madre Occidental exhibits a variable geologic character. The physiographically high altitudes above the coastal plain—1,500 to 2,000 m on the average, some higher than 3,000 m—evolved by effects of the differential erosion of thick extrusive volcanic sequences: intercalated andesites, rhyolites, tuffs, and ignimbrites making up a volcanic assemblage.
This assemblage overlies an older basement comprising Precambrian or Paleozoic metamorphic rocks and Mesozoic sedimentary or igneous rocks.
Figures & Tables
Economic Geology, Mexico
This volume was developed, produced, and privately printed in Mexico, in Spanish, by the late Ing. G.P. Salas in 1988, as a Mexican contribution to the Geology of North America, with the understanding that it would be translated into English for inclusion in the set. The translation is by Dr. Cecily Petzall of Caracas, Venezuela, with considerable figure translation and redrafting provided by GSA. Salas worked on the volume until his death, with much valuable help from Ing. Hugo Cortez Guzmán. The result is a valuable English-language synthesis of the information available to Salas in the early to mid-1980s about the geothermal, coal, and metal-mining sectors (and some non-metallic resources) of the economic geology of Mexico.