Boletín de la Sociedad Geológica Mexicana Volumen 68, núm. 2, 2016, p. 365-370 ttp://dx.doi.org/10.18268/BSGM2016v68n2a13

 Short Note

Geochronology of Mexican mineral deposits. V: the Peñón Blanco epithermal deposit Durango

 Antoni Camprubí^1,*, Tawn Albinson², Alexander Iriondo³

¹ Instituto de Geología, Universidad Nacional Autónoma de México. Ciudad Universitaria, 04510 Coyoacán, CDMX, México.
²Exploraciones del Altiplano, S.A. de C.V. Sinaloa 106 – oficina 302, Colonia Roma Norte, 06760 Cuauhtémoc, CDMX, Mexico.
³ Centro de Geociencias, Universidad Nacional Autónoma de México. Boulevard Juriquilla 3001, 76230 Querétaro, Qro., Mexico.
^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The low sulfidation epithermal deposits of the San Juan de Mogotes mineralized area in the Peñón Blanco district, central-eastern Durango, were dated in this study at 31.29 ± 0.08 Ma (adularia from crustiform veins, ⁴⁰Ar/³⁹Ar plateau age). Therefore, these deposits belong to the most productive metallogenic epoch—Oligocene—and are found in the most heavily mineralized region of Mexico—the western half of the Mesa Central, particularly around the San Luis–Tepehuanes fault zone and near its confluence with the Transversal de Parras (or Parras Transversal zone). At that time and in this region epithermal deposits and tin veins in association with fluorine-rich rhyolites (highly differentiated rhyolites) were the dominant types of deposits, and both occurred at a district scale, which is the case of the Peñón Blanco district, among others. Such characteristics suggest a possible genetic link between both types of deposits, research that would need to be specifically addressed in the future.

Keywords: Peñón Blanco, Durango, Mexico, epithermal deposits, low sulfidation, ⁴⁰Ar/³⁹Ar ages, adularia.

Resumen

 Los depósitos epitermales de baja sulfuración del área mineralizada de San Juan de Mogotes en el distrito de Peñón Blanco, Durango centro-oriental, son fechados en este estudio en 31.29 ± 0.08 Ma (adularia de vetas crustiformes, edad de meseta ⁴⁰Ar/³⁹Ar). Por lo tanto, estos depósitos pertenecen a la época metalogenética más productiva—oligocénica—y se encuentran en el área más densamente mineralizada de México—la mitad occidental de la Mesa Central, particularmente alrededor de la zona de falla de San Luis–Tepehuanes y cerca de la confluencia entre ésta y la Transversal de Parras. Durante dicha época y en esta región, las tipologías dominantes de yacimientos minerales son los depósitos epitermales y las vetas de estaño en asociación con riolitas ricas en flúor (riolitas altamente diferenciadas), y ambas tipologías se encuentran también a escala de distrito, que es el caso del distrito de Peñón Blanco, entre otros. Tales características sugieren un posible nexo genético entre ambas tipologías, tema que necesitaría ser investigado específicamente en el futuro.

Palabras clave: Peñón Blanco, Durango, México, depósitos epitermales, sulfuración baja, edades ⁴⁰Ar/³⁹Ar, adularia.

1. Introduction

The Peñón Blanco district in eastern-central Durango state (north-central Mexico) consists of several mineralized areas that contain epithermal deposits, named Yerbanís, Cerro Blanco, and San Juan de Mogotes (also known as La Esperanza) (Servicio Geológico Mexicano, 2003, 2004, 2005). The San Juan de Mogotes mineralized area contains silica sinter deposits that are associated with underlying kaolinized and alunitized rocks (Servicio Geológico Mexicano, 2003) that constitute an advanced argillic alteration assemblage, possibly as a result of steam-heated grounds. Such evidence was interpreted to be associated with low sulfidation epithermal deposits (Servicio Geológico Mexicano, 2003), which include the Lorena, Ángeles, Providencia and Guadalupe veins. Also, the San Juan de Mogotes area includes Sn and Hg showings (Servicio Geológico Mexicano, 2003), and exploration surveys conducted by Exploraciones Mineras Parreña S.A. de C.V. revealed significant Au and Ag concentrations in association with the aforementioned veins (Santiago Olavide, written communication, 2007). This area lies in the vicinity of the Avino-Zaragoza district, which contains tin veins associated with fluorine-rich rhyolites dated at 29.6 ± 0.1 Ma (Rb-Sr; Huspeni et al., 1984), as well as Au-Ag, polymetallic (Ag-Au-Pb-Zn-Cu) and fluorite epithermal veins (Servicio Geológico Mexicano, 2003, 2013), the dominant type of deposits in this district. Au-Ag and polymetallic+fluorite epithermal deposits in Mexico tend to belong to the low and intermediate sulfidation subtypes, respectively (Camprubí and Albinson, 2006, 2007).

The study region, near the central part of the western half of the Mesa Central, as part of the most productive metallogenic epoch (Albinson et al., 2001; Camprubí et al., 2003; Camprubí, 2013), is particularly rich in Oligocene mineral deposits (Figure 1). Metallogenesis during the Oligocene was associated with the most prominent ignimbrite flare-up in the Sierra Madre Occidental silicic large igneous province (Camprubí et al., 2003; Ferrari et al., 2005, 2007). This region is found around the confluence between the westernmost Parras transversal zone and the northwestern ending of the large San Luis–Tepehuanes fault zone (Nieto-Samaniego et al., 2005, 2007; Camprubí, 2013). Since the Late Cretaceous, many mineral deposits formed around this confluence, including an uncanny variety and quantity during a short period in the Oligocene (see Figures 8 and 13 in Camprubí, 2013).

In this paper, we present the first ⁴⁰Ar/³⁹Ar ages for low sulfidation epithermal deposits at the Peñón Blanco district, with the aim to better understand the metallogenic evolution of the heavily mineralized region of the northwestern part of the San Luis–Tepehuanes fault zone, in eastern Durango.

Figure 1. Simplified geological map of the westernmost ending of the Mesa Central in central Mexico, showing the approximate extent of the Oligocene volcanic rocks of the Sierra Madre Occidental silicic large igneous province (based on Ferrari et al., 2005, 2007), the approximate extent of the San Luis–Tepehuanes fault zone (based on Nieto-Samaniego et al., 2005, 2007), and the ore deposits that were formed during the Oligocene (based on Camprubí, 2013). The term ‘skarns’ stands for sulfide (non-iron oxide) skarns whereas ‘IOCG’ stands for the ‘clan’ of iron oxide copper gold deposits, or magmatic-hydrothermal iron oxide deposits, which includes iron oxide skarns. Cities are indicated by gray pentagons.

2. Methods and results

A pure mineral separate of adularia from epithermal vein material from the San Juan de Mogotes mineralized area in the Peñón Blanco district was dated by ⁴⁰Ar/³⁹Ar geochronology (Figure 2 and Table 1). The analyzed sample (SJ-4) corresponds to adularia crystals within crustiform quartz bands in low sulfidation mineralization from the Lorena vein. The vein material was ground down to particles that ranged in size from 250 to 180 µm and were separated using heavy liquids and hand picking to a purity of > 99 %. The sample was washed in acetone, alcohol, and deionized water in an ultrasonic cleaner to remove dust and then re-sieved by hand using a 180-µm sieve.

Aliquots of the adularia sample (~ 20 mg) were packaged in copper capsules and sealed under vacuum in quartz tubes. The sample aliquots were then irradiated in package number KD53 for 20 hours in the central thimble facility at the TRIGA reactor (GSTR) at the U.S. Geological Survey in Denver, Colorado. The monitor mineral used in the package was Fish Canyon Tuff sanidine (FCT-3) with an age of 27.79 Ma (Kunk et al., 1985; Cebula et al., 1986) relative to MMhb-1 with an age of 519.4 ± 2.5 Ma (Alexander et al., 1978; Dalrymple et al., 1981). The type of container and the geometry of the sample and standards were similar to that described by Snee et al. (1988).

The adularia sample was analyzed at the U.S. Geological Survey Thermochronology lab in Denver, Colorado, using the ⁴⁰Ar/³⁹Ar step-heating method and a VG Isotopes 1200B mass spectrometer fitted with an electron multiplier. For additional information on the analytical procedure see Kunk et al. (2001). The analyzed sample yielded a plateau age at 31.29 ± 0.08 Ma and it is supported, within analytical error, by the less precise isochron age at 31.30 ± 0.20 Ma.

Figure 2. 40Ar/39Ar age spectrum and isochron for the SJ-4 adularia sample from the Lorena vein in the San Juan de Mogotes mineralized zone of the Peñón Blanco mining district, central-eastern state of Durango.

Table 1. 40Ar/39Ar step-heating data for the San Juan de Mogotes epithermal deposits, Peñón Blanco, Durango. Ages calculated assuming an initial 40Ar/36Ar = 295.5 ± 0. All precision estimates are at the one sigma level of precision. Ages of individual steps do not include error in the irradiation parameter J. No error is calculated for the total gas age.

3. Discussion and conclusions

The age for adularia sample SJ-4 from vein material of the epithermal deposits at the San Juan de Mogotes mineralized area in the Peñón Blanco district is 31.29 ± 0.08 Ma (early Oligocene). This is the first age determination on mineralization material from this region and time span (Table 2), and corresponds to the range of ages that is most characteristic for Cenozoic ore deposits in Mexico. Not only does this deposit belong to the most metallogenetically productive epoch, but also to the region that contains the highest concentration in magmatic-hydrothermal ore deposits in Mexico; that is, the western portion of the Mesa Central, particularly in the vicinities of the San Luis–Tepehuanes fault zone, during the Oligocene (Camprubí, 2013). The metallogenic importance of this time and space frame is illustrated by the occurrence of what is currently the largest silver deposit in the world (Fresnillo, in Zacatecas).

The dominant types of deposits in the western half of the Mesa Central during the Oligocene are epithermal deposits and tin veins in association with fluorine-rich rhyolites (Figure 1). The possible genetic link between Au-Ag or polymetallic epithermal deposits with tin veins associated with fluorine-rich rhyolites (including Sn-Hg-F-Sb deposits), and the associated fluorite hydrothermal veins, remains to be characterized. Such is also the case of the southeastern ending of the Mesa Central in San Luis Potosí (Camprubí, 2013), in which topaz rhyolites are conspicuous (Leroy et al., 2002; Rodríguez-Ríos et al., 2007, 2013). Fluorite is a common mineral within or in association with epithermal deposits in the study region, either forming individual veins (e.g., Clark et al., 1977) or as an accessory mineral (Servicio Geológico Mexicano, 2013). No causality between the occurrence of highly differentiated fluorine-rich rhyolites (Leroy et al., 2002; Rodríguez-Ríos et al., 2007, 2013) and fluorite-rich epithermal deposits has been soundly interpreted to date, but it is a likely hypothesis for future studies. Central and eastern Durango poses as an ideal region for research about possible genetic links between epithermal deposits and tin veins associated with fluorine-rich rhyolites due to their close time and space distribution (Clark et al., 1977; Huspeni et al., 1984; Tuta et al., 1988; Camprubí, 2013). This is also the case for the Sombrerete and Sierra de Chapultepec deposits in Zacatecas (Albinson, 1988), which are epithermal and tin vein deposits, respectively, also associated with the San Luis–Tepehuanes fault zone (Figure 1; Camprubí, 2013). Such correspondences occur even at the district scale, which is the case of the grouping of deposits at Avino and Coneto de Comonfort, both dominantly epithermal deposits (Ponce-Sibaja and Gutiérrez-Tapia, 1978; Servicio Geológico Mexicano, 2003, 2013), and scant tin veins are also found in the Peñón Blanco district itself (Servicio Geológico Mexicano, 2003). The formation of tin veins associated with fluorine-rich rhyolites continued briefly into the Miocene as the volcanic activity of the Sierra Madre Occidental silicic large igneous province shrunk dramatically southwards prior to the opening of the Gulf of California and the rearrangement of volcanism into the Trans-Mexican Volcanic Belt (Camprubí, 2013). Tin vein deposits were abundantly accompanied by epithermal deposits in that case as well (see Figures 9 and 10 in Camprubí, 2013).

Table 2. Hydrothermal mineral deposits in central-eastern Durango, with similar ages to those in the Peñón Blanco district.
Key: IS = Intermediate sulfidation; LS = low sulfidation; w.r. = whole rock. Asterisks (*) denote that the analyzed samples correspond to host rocks, whereas double asterisks (**) denote that the analyzed samples correspond to hydrothermal minerals.

Acknowledgements

This study was financed by means of CONACYT grant number 155662. The authors wish to thank Michael Kunk for providing access and guidance to perform the ⁴⁰Ar/³⁹Ar geochronology studies at the U.S. Geological Survey Thermochronology Lab in Denver, Colorado. Santiago Olavide and Jorge Islas are thanked for their insight in the field. The age determination in this study was first mentioned by Camprubí (2013). Formal reviews were conducted by two anonymous reviewers, whose comments helped to improve this paper.

References

Albinson, T., 1988, Geologic reconstruction of paleosurfaces in the Sombrerete, Colorada, and Fresnillo districts, Zacatecas state, Mexico: Economic Geology, 83, 1647-1667.

Albinson, T., Norman, D.I., Cole, D., Chomiak, B.A., 2001, Controls on formation of low-sulfidation epithermal deposits in Mexico: constraints from fluid inclusion and stable isotope data, in Albinson, T., Nelson, C.E. (eds.), New mines and discoveries in Mexico and Central America: Society of Economic Geologists Special Publication Series, 8, 1-32.

Alexander, E.C.Jr., Mickelson, G.M., Lanphere, M.A., 1978, Mmhb-1: a new ⁴⁰Ar/³⁹Ar dating standard, in Zartman, R.E. (ed.), Short papers of the fourth international conference, geochronology, cosmochronology, and isotope geology: U.S. Geological Survey Open-File Report, 78-701, 6-8.

Camprubí, A., 2013, Tectonic and metallogenic history of Mexico, inColpron, M., Bissig, T., Rusk, B.G., Thompson, J.F.H. (eds.), Tectonics, metallogeny, and discovery: the North American Cordillera and similar accretionary settings: Society of Economic Geologists, Special Publication, 17, 201-243.

Camprubí, A., Albinson, T., 2006, Depósitos epitermales en México: actualización de su conocimiento y reclasificación empírica: Boletín de la Sociedad Geológica Mexicana, 58 (1), 27-81.

Camprubí, A., Albinson, T., 2007, Epithermal deposits in México – an update of current knowledge, and an empirical reclassification, in Alaniz-Álvarez, S.A., Nieto-Samaniego, A.F. (eds.), Geology of México: Celebrating the Centenary of the Geological Society of México: The Geological Society of America Special Paper, 422, 377-415.

Camprubí, A., Ferrari, L., Cosca, M.A., Cardellach, E., Canals, À., 2003, Ages of epithermal deposits in Mexico: regional significance and links with the evolution of Tertiary volcanism: Economic Geology, 98, 1029-1037.

Cebula, G.T., Kunk, M.J., Mehnert, H.H., Naeser, C.W., Obradovich, J.D., Sutter, J.F., 1986, The Fish Canyon Tuff: A potential standard for the ⁴⁰Ar/³⁹Ar and fission track dating methods: Terra Cognita, 6, 140.

Clark, K.F., Carrasco, M.L., Damon, P.E., Sandoval, H., 1977, Posición estratigráfica y distribución en tiempo y espacio de mineralización en la provincia de la Sierra Madre Occidental, en Durango, México: Pachuca, Hidalgo, Consejo de Recursos Minerales, unpublished report.

Clark, K.F., Damon, P.E., Schutter, S.R., Shaffiqullah, M., 1979, Magmatismo en el norte de México en relación a los yacimientos metalíferos, in AIMMGM Memoria Técnica XIII: México D.F., Asociación de Ingenieros de Minas, Metalurgistas y Geólogos de México (AIMMGM), 8-57.

Dalrymple, G.B., Alexander, E.C., Lanphere, M.A., Kraker, G.P., 1981, Irradiation of samples for ⁴⁰Ar/³⁹Ar dating using the Geological Survey TRIGA reactor: U.S. Geological Survey Professional Paper, 1176, 55 p.

de la Garza, V., Olavide, S., Villasuso, R., 2001, Geology and ore deposits of the La Ciénega gold district, Durango, Mexico, in Albinson, T., Nelson, C.E. (eds.), New mines and discoveries in Mexico and Central America: Society of Economic Geologists Special Publication Series, 8, 87-93.

Ferrari, L., Valencia-Moreno, M., Bryan, S., 2005, Magmatismo y tectónica en la Sierra Madre Occidental y su relación con la evolución de la margen occidental de Norteamérica: Boletín de la Sociedad Geológica Mexicana, 57, 343-378.

Ferrari, L., Valencia-Moreno, M., Bryan, S., 2007, Magmatism and tectonics of the Sierra Madre Occidental and its relation with the evolution of the western margin of North America, in Alaniz-Álvarez, S.A., Nieto-Samaniego, Á.F. (eds.), Geology of México: Celebrating the Centenary of the Geological Society of México: Geological Society of America Special Paper, 422, 1-39.

Huspeni, J.R., Kesler, S.E., Ruiz, R., Tuta, Z., Sutter, J.F., Jones, L.M., 1984, Petrology and geochemistry of rhyolites associated with tin mineralization in Northern Mexico: Economic Geology, 79, 87-105.

Kunk, M.J., Sutter, J.F., Naeser, C.W., 1985, High-precision ⁴⁰Ar/³⁹Ar ages of sanidine, biotite, hornblende, and plagioclase from the Fish Canyon tuff, San Juan volcanic field, South-central Colorado [abs.]: Geological Society of America Abstracts with Programs, 17, 636.

Kunk, M.J., Winick, J.A., Stanley, J.O., 2001, ⁴⁰Ar/³⁹Ar age-spectrum and laser fusion data for volcanic rocks in west central Colorado: U.S. Geological Survey Open-File Report, 01-472, 94 p.

Labarthe-Hernández, G., Tristán-González, M., Barboza-Gudiño, J.R., Mata-Segura, J.L., 1996, Cartografía Geológica 1:10,000 del área de La Ciénega y su correlación con otros distritos mineros de la Sierra Madre Occidental en el Estado de Durango: Universidad Autónoma de San Luis Potosí, Instituto de Geología, (Preparado para Peñoles), 86 p. (inédito).

Leroy, J.L., Rodríguez-Ríos, R., Dewonck, S., 2002, Les rhyolites à topaze de la région de San Luis Potosi (Mexique): caractéristiques des laves et conditions de croissance des topazes: Bulletin de la Societé Géologique de France, 173, 579-588.

Nieto-Samaniego, Á.F., Alaniz-Álvarez, S.A., Camprubí, A., 2005, La Mesa Central de México: estratigrafía, estructura y evolución tectónica cenozoica: Boletín de la Sociedad Geológica Mexicana, 57 (3), 285-318.

Nieto-Samaniego, Á.F., Alaniz-Álvarez, S.A., Camprubí, A., 2007, The Central Mesa of México: stratigraphy, structure and tectonic evolution during the Cenozoic, in Alaniz-Álvarez, S.A., Nieto-Samaniego, A.F. (eds.), Geology of México: Celebrating the Centenary of the Geological Society of México, The Geological Society of America Special Paper, 422, 41-70.

Ponce-Sibaja, B., Gutiérrez-Tapia, R.L., 1978, Aplicación de técnicas de estudios especiales para apoyo de obras de exploración en el distrito minero de Coneto de Comonfort, Dgo., in VII Seminario Interno sobre Exploración Geológico-Minera: Pachuca, Hidalgo, Consejo de Recursos Minerales, 601-643.

Rodríguez-Ríos, R., Aguillón-Robles, A., Leroy, J.L., 2007, Evolución petrológica geoquímica de un complejo de domos topacíferos en el Campo Volcánico de San Luis Potosí (México): Revista Mexicana de Ciencias Geológicas, 24, 328-343.

Rodríguez-Ríos, R., Tristán-González, M., Aguillón-Robles, A., 2013, Estructura y geoquímica de un grupo de domos dacíticos del norponiente del Campo Volcánico de San Luis Potosí, México: Boletín de la Sociedad Geológica Mexicana, 65, 109-122.

Servicio Geológico Mexicano, 2003, Carta geológico-minera Ignacio Ramírez 1:50000 G13-D63, Durango: Pachuca, Hidalgo, Servicio Geológico Mexicano, Secretaría de Economía.

Servicio Geológico Mexicano, 2004, Carta geológico-minera Peñón Blanco 1:50000 G13-D53, Durango: Pachuca, Hidalgo, Servicio Geológico Mexicano, Secretaría de Economía.

Servicio Geológico Mexicano, 2005, Carta geológico-minera Cuencamé 1:50000 G13-D54, Durango: Pachuca, Hidalgo, Servicio Geológico Mexicano, Secretaría de Economía.

Servicio Geológico Mexicano, 2013, Geological-mining monograph of the state of Durango: Pachuca, Hidalgo, Servicio Geológico Mexicano, Secretaría de Economía, 527 p.

Smith, L., 1995, Evolución dinámica y ocurrencia de mineralización, veta El Herrero, in XXI Convención Nacional, Asociación de Ingenieros de Minas, Metalurgistas y Geólogos de México, A.C., Acapulco, Guerrero, Memorias Técnicas, 13 p.

Snee, L.W., Sutter, J.F., Kelly, W.C., 1988, Thermochronology of economic mineral deposits: Dating the stages of mineralization at Panasqueira, Portugal, by high precision ⁴⁰Ar/³⁹Ar age spectrum techniques on muscovite: Economic Geology, 83, 335-354.

Tuta, Z.H., Sutter, J.F., Kesler, S.E., Ruiz, J., 1988, Geochronology of mercury, tin, and fluorite mineralization in northern Mexico: Economic Geology, 83, 1931-1942.

Manuscript received: September 28, 2015.
Corrected manuscript received: January 12, 2016.
Manuscript accepted: January 18, 2016.