Characterization of alteration zones and intrusive phases for the prospectus "stock of Piedra Sentada" (Saint Lucia) Cauca, Colombia
Abstract
The Santa Lucia porphyritic stock is located in Cauca department, in the western flank of the central cordillera, specifically in the Santa Lucia rural settlement of La Sierra municipality. It corresponds to a hypoabyssal body from the Miocene age which intrudes basalts form Barroso - Amaime complex; it is probably inclined in predominant northeast direction. This characterization is based on the log of 5 vertical drillings made and located by the Japan International Cooperation Agency (JICA), in agreement to the reported geophysical anomalies for the area of study. The stock presents mineralogical and hydrothermal characteristics proper of porphyritic gold-copper deposits, and it is genetically related to the emplacement of 4 intrusive pulses of variable composition between dacite-andesite. They are contained in 2 intrusive phases: an early phase characterized by presenting dominant potassic- biotitic alteration and veinlet typical of high temperature (type M, A, EB, B) which presents the major economic interest in the system; and a postmineral phase with dominant propylitic alteration and typical veinlet (type B, D, CI+Ep) located in the interior part of the deposit. The porphyritic stock presents overprint of veinform systems in the south of the deposit; they correspond preliminarily to low-sulfidation epithermal features. Given the present characteristics in the deposit, its presence is associated to the metallogenic miocene belt existing in the southwestern part of Colombia.
Keywords
hidrotermal alteration, intruding phases, log, porphyry, Santa Lucia
References
- Burnham, C.W.; Ohmoto; H (1980): Late-stage processes of felsic magmatism. In Granitic mamatism and related mineralization (Ishibara, S.; Takenouchi, S.; editors), Mining Geology, Special Issue, No. 8, pp. 1-11.
- Camus, F. (2003): Geología de los sistemas porfíricos en los Andes de Chile, Servicio Nacional de Geología y Minería, Santiago, Chile.
- Carten, R.B., (1987): Sodium- Calcium metasomatism: Chemical, temporal, and spatial relationships at the Yerington, Nevada, Porphyry copper deposit: ECONOMIC GEOLOGY, vol. 81, pp. 1174-1186.
- Dilles, J.Ii., and Einaudi, M.T., (1992): Wall-rock alteration and hydrothermal flow paths about the Ann-Mason porphyry copper deposits, Nevada: A 6 Km vertical reconstruction, ECONOMIC GEOLOGY, vol. 87, pp. 1963-2001.
- García, C.A., (2007): Caracterización petrográfica y metalográfica del prospecto pórfido aurífero Dos Quebradas la Cumbre, Quinchía, Risaralda, Tesis de grado de geología, Universidad de Caldas.
- Gustafson, L.B., and Hunt, J.P., (1975): The porphyry copper deposit at El Salvador, Chile. Economic Geology, v. 70, Canada.
- Etayo, F. et al. (1983): Mapa de terrenos geológicos de Colombia. INGEOMINAS. Publicación Geológica Especial, 14 (I), pp. 1-235. Bogotá.
- Heinrich, C.A., Driesner, T., Stefansson, A., Seward, T.M., (2004): Magmatic vapor contraction and the transport of gold from the porphyry environment to ephitermal ore deposits, Geology, v. 32, (9) pp. 761-764, United States.
- Hubach, E., (1955): El Cauca, las unidades geográficas y geológicas del departamento y los recursos del suelo y del subsuelo, I-1107, INGEOMINAS, Colombia.
- Instituto Colombiano de Geología y Minería (2004): Estudio geológico integral para la búsqueda de recursos minerales en el sector Buriticá (Antioquia) - Viterbo (Risaralda) Colombia, INGEOMINAS, 2004, p. 157.
- Japan Internacional Cooperation Agency (JICA), (1987): Informe sobre exploración de minerales del área de Almaguer, Departamento del Cauca, Colombia. Compilación Fases I, II y III.
- Jaramillo, L. y Escobar, R., (1980): Cinturones de pórfidos cupríferos en las cordilleras colombianas, I- 1801, INGEOMINAS. Bogotá, Colombia.
- Kerr. P. (1965): Mineralogía óptica, Mc.GrawHill, Madrid.
- Marulanda, N. (1976): Geología y geoquímica del área de Piedra Sentada, Municipio de El Bordo, Cauca, I- 1703 INGEOMINAS. Popayán, Colombia.
- Marulanda, N., (1978): Geología y prospección geoquímica del área mineralizada La Vega y Almaguer. I-1762, INGEOMINAS. Popayán, Colombia.
- Molano, J.C., Londoño, S.E., Mojica, J., y otros. (2003): Catálogo de las propiedades mineralógicas, físicas y químicas de los yacimientos auríferos primarios de los departamentos Cauca, Nariño y Valle del Cauca, INGEOMINAS,Cali, Colombia.
- Muntean, J. and Einaudi, M., (2000): Porphyry gold deposits of the Refugio District, Maricunga Belt, Northern Chile. Economic Geology, Vol 95, pp. 1445-1472. Canada.
- Orrego, A. Acevedo, A. (1993): Geología de la plancha 364-Timbío, INGEOMINAS. Bogotá, Colombia.
- Perelló, J.; Cabello, J. (1989): Pórfidos cupríferos ricos en oro, una revisión,Revista geológica de chile, Vol. 16, (1), pp. 73-92.
- Seedorff, E. et al., (2005): Porphyry deposits: characteristics and origin of hypogene Features, Society of economist Geologists, Inc. Economic Geology 100th Anniversary Volume, Canada.
- Sillitoe, R., (2000): Gold-rich porphyry deposits: descriptive and genetic models and their role in exploration and discovery. Reviews in Economic Geology, Volume 13. Canada.
- Sillitoe, R. and Perello, J., (2005): Andean copper province: tectonomagmatic settings, deposit types, metallogeny, exploration, and discovery. Society of Economist Geologists, Inc. Economic Geology 100th Anniversary Volume. Canada.
- Simmons, S., White, N. and John, D., (2005): Geological characteristics of epithermal precious and base metal deposits. Society of Economist Geologists, Inc. Economic Geology 100th Anniversary, Canada.
- Paris, G. y Marín, P., (1979): Generalidades acerca de la geología del Departamento del Cauca,INGEOMINAS,Popayán, Colombia.
- Vila, T. and Sillitoe, R., (1991): Gold-rich porphyry systems in the Maricunga Belt, Northern Chile, Economic Geology, Vol. 86. Canada.
- Unal-Carboandes S.A. (2008): Socialización y delimitación de prospectos en las áreas Piedra Sentada y Dominical, Departamento del Cauca, Colombia, Informe interno, UNAL y CARBOANDES S.A. Bogotá, Colombia.