El Alacran

Porphyry copper prospect in Sonora, Mexico

Names and other identifiers

Alternate names Cananea, Santa Barbara, Dora, Mixteca, Flores, De Hoyos, Slyther-Mackay-Jones, Goosh
Tract name Western Sierra Madre Occidental and Laramide Central (003pCu3007x)
Site status prospect

Geographic location

Country Mexico
State or province Sonora
Geographic location -110.200946998, 30.844819187
Geologic map unit -110.200946998, 30.844819187
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 60.9Ma
Age determination method Re-Os molybdenite
Age range 60.9 ±0.2 Ma
Age reference Barra and others (2005)
Minerals chalcocite, chalcopyrite, pyrite
Associated rocks quartz latite porphyry, andesite, volcaniclastics
Tectonic setting continental margin
Stratigraphic age Paleocene

Commodity and development information

Development status Prospect
Major commodities Cu, Mo
Gold-Moly ratio -9999

Reference information

Comments Potential resources: 3100 t Cu; reserves: 700,000 t 0.5% Cu, 2.4 Mt 0.35% Cu (Perez-Segura, 1985). Potassic alteration dated at 55.9 Ma; (55.4 ±1.2 Ma andesite, 56.7 ±1.2 Ma biotite). WNW trending area of intense illite and kaolin alteration 1 by 3 km defines surface expression of the deposit; small granodiorite porphyry with quartz vein stockwork (Cox and others, 2006). Location: abandoned mine on Servicio Geológico Mexicano 250K map. Valencia-Morena and others (2007) list 2.4 Mt at 0.35% Cu. High-level Laramide porphyry copper deposit occupying elongate area of 2.7 by 6.0 km. Supergene copper enriched ""blanket"" underlying a leached cap characterized by a chalcocite zone which grades downward into a bornite-digenite-covellite zone and then into lower-grade material. Geology: Late Cretaceous to Early Tertiary andesitic volcaniclastic rocks with local quartz latite intruded by a small quartz latite porphyry stock. Alteration: argillization-oxidation; potassic, phyllic, propylitic, tourmalinization, silicification. Silicification generally occurs near surface with kaolinization and primary sulfides 5 to 200+ m below.
Study area name Mexico
References Dean and Guilbert (1981); Pérez-Segura (1985); Terán-Martínez and others (1999); U.S. Geological Survey (2007); Barra and others (2005); Cox, Miller and Woodbourne (2006); Valencia-Morena and others (2007)
Site reference Hammarstrom and others (2010)
Barra, Fernando; Ruiz, Joaquin; Valencia, V.A.; Ochoa-Landín, Lucas; Chesley, J.T., and Zürcher, Lukas, 2005, Laramide porphyry Cu-Mo mineralization in northern Mexico—Age constraints from Re-Os geochronology in molybdenite: Economic Geology, v. 100, p. 1605–1616. (Also available at http://dx.doi.org/10.2113/gsecongeo.100.8.1605.)Cox, D.P., Miller, R.J., and Woodbourne, K.L., 2006, The Laramide Mesa Formation and the Ojo de Agua caldera, southeast of the Cananea copper mining district, Sonora, Mexico: U.S. Geological Survey Scientific Investigations Report 2006-5022, 7 p., accessed January 7, 2014, at http://pubs.usgs.gov/sir/2006/5022/.
Dean, D.A., And Guilbert, J.M., 1981, El Alacran—A high level porphyry copper deposit, Sonora, Mexico: Geological Society of America Abstracts with Programs, v. 13, no. 2, p. 51.
Pérez-Segura, E., 1985, Carta Metalogenética de Sonora 1:250,000—Una interpretación de la metalogenia de Sonora: Gobierno del Estado de Sonora Publicación 7, 64 p.
Terán-Martínez, G.E., Cerecero-Luna, Miguel, Mendoza-Romero, Macario, Castro-Escárrega, J.J., and García-Cortez, J.A., 1999, Carta geológico-minera, Cananea H12-5, Sonora [Mexico]: Pachuca, Hidalgo, Servicio Geológico Mexicano, 1 sheet, scale 1:250,000.
U.S. Geological Survey, 2007, Mineral Resources Data System (MRDS): U.S. Geological Survey database, accessed December 15, 2007, at http://tin.er.usgs.gov/mrds/.Valencia-Moreno, M., Ochoa-Landín, Lucas, Noguez-Alcántara, Benito, Ruiz, Joaquin, Pérez-Segura, Efrén, 2007, Geological and metallogenetic characteristics of the porphyry copper deposits of México and their situation in the world context, in Alaniz-Álvarez, S.A., and Nieto-Samaniego, Á.F., eds., Geology of México—Celebrating the centenary of the Geological Society of México: Geological Society of America Special Paper 422, p. 433–458. (Also available at http://specialpapers.gsapubs.org/content/422/433/F8.expansion.html.)