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U.S. Department of the Interior U.S. Geological Survey U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Prepared in cooperation with New Mexico Bureau of Mines and Mineral Resources 1997 MINERAL AND ENERGY RESOURCES OF THE MIMBRES RESOURCE AREA IN SOUTHWESTERN NEW MEXICO This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Cover: View looking south to the east side of the northeastern Organ Mountains near Augustin Pass, White Sands Missile Range, New Mexico. Town of White Sands in distance. (Photo by Susan Bartsch-Winkler, 1995.) MINERAL AND ENERGY RESOURCES OF THE MIMBRES RESOURCE AREA IN SOUTHWESTERN NEW MEXICO By SUSAN BARTSCH-WINKLER, Editor ____________________________________________________ U. S GEOLOGICAL SURVEY OPEN-FILE REPORT 97-521 U.S. Geological Survey Prepared in cooperation with New Mexico Bureau of Mines and Mineral Resources, Socorro U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Mark Shaefer, Interim Director For sale by U.S. Geological Survey, Information Service Center Box 25286, Federal Center Denver, CO 80225 Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government MINERAL AND ENERGY RESOURCES OF THE MIMBRES RESOURCE AREA IN SOUTHWESTERN NEW MEXICO Susan Bartsch-Winkler, Editor Summary Mimbres Resource Area is within the Basin and Range physiographic province of southwestern New Mexico that includes generally north- to northwest-trending mountain ranges composed of uplifted, faulted, and intruded strata ranging in age from Precambrian to Recent. Rocks within the province have significant mineral deposits, many associated with tectonic structures related to Basin and Range development, within 63 mining districts. This report includes a compilation of all known metallic and industrial mineral deposits and occurrences within Grant, Hidalgo, Luna, and Doña Ana Counties in southwestern New Mexico and historical data on their production. The known deposits are described by 25 mineral deposit models and an assessment of the potential for unknown deposits within one kilometer of the surface for each model type is included. Industrial mineral and energy resources are recognized, along with an assessment of sand and gravel and crushed rock resources using new and innovative techniques. Also described in this report are (1) a compilation of the geology of each mountain range; (2) a description of geological events that took place throughout geologic time; (3) a geophysical analysis; (4) descriptions of resource assessment techniques; (4) a complete reference list; and (5) a compilation of stratigraphic unit names. ARC/INFO files used in making resource assessments are separate files on the CD-ROM. The Mimbres Resource Area includes the most mineralized area in New Mexico and the highest metallic mineral production in the State. Total production from the study area is estimated to include 15.7 billion lbs of copper, 100 million oz of silver, 1.2 million oz of gold, 651 million lbs of lead, and 2.8 billion lbs of zinc, and accounts for more than 90 percent of the total copper, zinc, and silver production from New Mexico from 1848 until 1993. Production from the area has also amounted to 89 percent of the lead and 46 percent of the gold in New Mexico. Currently, metal mining operations are in the Silver City area (Chino, Tyrone, and Continental mines), and in the Lordsburg and Steeple Rock districts. Twenty-five deposit types occur within the study area. Worldwide statistics on these deposit types were used in conjunction with other geological characteristics to determine the probability of undiscovered deposits of these types in the Mimbres Resource Area. Results of the mineral resource assessment indicate a 90 percent probability for expected mean tonnages of 200 tonnes Au, 11,000 tonnes Ag, 9.4 million tonnes Cu, 9.1 million tonnes Fe, 450,000 tonnes Mn, 300,000 tonnes Mo, 470,000 tonnes Pb, 85 tonnes WO3, and 600,000 tonnes Zn that are contained in an estimated total 2.5 billion tonnes of mineralized material. There are 9 chances out of 10 that the study area will contain these or greater tonnages. Gross in-place values (GIPV) of expected tonnages show that copper has the highest value, with approximately $77 billion or 63 percent of the mean GIPV of all of the metals deposits in the study area. Iron in skarn deposits has the next highest value, with approximately $15 billion or 12 percent of the total GIPV, and molybdenum in porphyry deposits is the third highest, with approximately $13 billion or 10 percent of the total GIPV. By far the highest GIPV for any deposit type present is porphyry copper- molybdenum deposits, with an estimated total of $89 billion in gold, silver, copper, lead, zinc, and molybdenum. The single favorable area with the highest GIPV is the Peloncillo area in the Mogollon-Datil volcanic field, which was assessed for porphyry deposits. This area has an expected mean GIPV of $21 billion (over 17 percent of the total). Aggregated multiple favorable areas indicate that the Piños Altos-Santa Rita area has the greatest GIPV ($24 billion), and the Peloncillo Mountains contains the second greatest GIPV ($22 billion). Industrial mineral commodities are overshadowed in importance by the metallic minerals, but they are nonetheless highly varied and may be of significance as the area increases in population. Known deposits or occurrences of aggregate, alum, caliche, clay, dimension stone, travertine, calcite, talc, fluorspar and barite, gemstones and collectible minerals, guano, gypsum, iron, jarosite, manganese, marble, perlite, ricolite, scoria and pumice, and zeolite are present in the area. Geothermal resources, currently utilized in a small way, may be of greater importance in the future in southwest New Mexico. Coal and oil and gas resources are currently only of limited importance in the study area. INTRODUCTION The sparsely vegetated Mimbres Resource Area encompasses about 14,198 mi2 (36,773 km2; 9,086,720 acres), including the counties of Grant, Hidalgo, Luna, and Do–a Ana, in southwestern New Mexico. Of the total, the U.S. Bureau of Land Management (BLM) manages about 14,000 sq mi (36,260 km2; 9 million acres) on the surface and about 11,000 sq mi (28,490 km2; 7.5 million acres) in the subsurface (table 1-1; figure 1-1). The study area is within the "Colorado Plateau semi-desert province" and the "Arizona-New Mexico mountains semi-desert-open woodland-coniferous forest-alpine meadow province" ecoregions of the United States (Bailey, 1994). High plains regions in the Mimbres Resource Area range in altitude from about 1068m to 1373m; mountainous regions attain altitudes of about 2745m . Numerous national forests, wilderness areas, refuges, ranges and facilities, monuments, and State parks lie within the Mimbres Resource Area boundaries (figure 1-2). The largest cities within the resource area boundary include Las Cruces, Deming, Lordsburg, and Silver City. Federal wilderness lands [Wilderness Study Areas (WSA) and Instant Study Areas (ISA)] include: Aden Lava Flow WSA Alamo-Hueco Mountains WSA Big Hatchet Mountains WSA Blue Creek WSA Cedar Mountains WSA Cookes Range WSA Cowboy Springs WSA Florida Mountains WSA Gila WSA Guadalupe Canyon ISA Las Uvas Mountains WSA Organ Mountains WSA Redrock WSA Robledo Mountains WSA West Portrillo Mountains WSA National Forest (NF) lands include: Coronado NF Gila NF Other Federal lands include: Fort Bliss Military Reservation NASA Test Facility San Andres National Wildlife Refuge (NWR) White Sands National Monument (NM) White Sands Missile Range (WSMR) New Mexico State Parks (SP) include: City of Rocks SP Leasburg Dam SP Pancho Villa SP Rockhound SP The western boundary of the study area is the New Mexico-Arizona state line, the southern boundary is the border with Mexico, and the southeastern tip borders the state of Texas. The populous Rio Grande valley in southern Do–a Ana County and isolated parts of valleys in Hidalgo and Luna Counties irrigated by wells are less typical than the sparsely settled, arid to semiarid regions that are used primarily for ranching and that comprise most of the rest of the study area. PURPOSE AND METHODOLOGY As the NationÕs principal conservation agency, the Department of the Interior has responsibility for the countryÕs public lands and natural resources. As part of that responsibility, the Department assesses the mineral and energy resources and works to assure that their development (or non-development) is in the best interest of the country. Throughout its history, the U.S. Geological Survey (USGS), an agency of the Department of the Interior, has acquired mineral-resource information on the public lands and provided assessments to agencies such as the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS), who are caretakers and managers of public lands and have jurisdiction over surface and subsurface mineral rights. Initially, mineral deposit models for quantitative mineral-resource assessments were necessarily derived when the 1964 Wilderness Act required that mineral values of Wilderness lands be determined, as a precaution against the day when a national emergency might make their mining necessary (Ovenshine, 1986). Quantitative mineral-resource assessments and analyses of mineral resources
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