Cordilleran Epithermal Cu-Zn-Pb-(Au-Ag) Mineralization in the Colquijirca District, Central Peru: Deposit-Scale Mineralogical Patterns

Abstract

Abstract0361-0128/09/3845/905-40 905 Introduction PERU is a major producer of silver, copper, zinc, lead, bismuth, tin, and gold. Of these metals, zinc, lead, silver, tin, and bismuth are produced dominantly from deposits of several styles but all sharing the following major features: (1) polymetallic (Cu-Zn-Pb-Ag-Au) suite; (2) zoned from inner Cu-bearing to outer Zn-Pb−bearing ores; (3) sulfide-rich character, commonly massive; and (4) primary occurrence as open-space fillings (veins, breccia bodies) in silicate host rocks and as replacements in carbonate rocks. Sawkins (1972) classified ores displaying these features as Cordilleran vein-type deposits. Later, Einaudi (1982) described these deposits as Cordilleran vein or lode deposits within the context of porphyry-related systems. Additional general discussions on Cordilleran vein deposits are given by Guilbert and Park (1986), Bartos (1989), andBendezú (2009). Recently, this type of mineralization has been termed "zoned base metal veins" by Einaudi et al. (2003); however, a clear zonation is not always recognized, and the ores in many districts are dominantly mantos and not veins, and they commonly contain Au and Ag in addition to base metals. We therefore prefer the more general term "Cordilleran polymetallic deposits" Fontboté and Bendezú, 2009 AbstractAt Colquijirca, central Peru, a Miocene diatreme-dome complex is associated in space and time with several large epithermal polymetallic (Cu-Zn-Pb-Au-Ag) deposits of the Cordilleran class. Of these deposits, Smelter and Colquijirca, located in the northern sector of the district, are part of a continuously mineralized northsouth corridor that extends for nearly 4 km outward from the diatreme-dome complex and to depths of 1 km below surface. This corridor is zoned from Cu-(Au) ores in its inner parts (Smelter deposit) to peripheral ZnPb-(Ag) ores (Colquijirca deposit). The Smelter-Colquijirca corridor has undergone minor erosion, providing a good example of a nearly intact paleo-epithermal system of the Cordilleran class.This description of the hypogene mineralogical patterns of the Smelter-Colquijirca corridor leads to the proposal that they are the result of superimposition in time and space of three main stages. During an early quartzpyrite stage, in which basically no economic ore deposition occurred, carbonate rocks surrounding the Marcapunta diatreme-dome complex were replaced by quartz and pyrite. This was followed by the main ore stage, which was largely superimposed on the quartz-pyrite replacements and produced zonation of ore minerals and metals along much of the Smelter-Colquijirca corridor. The zoning from Cu ores to Zn-Pb ores is complex and comprises a number of distinct and well-defined zones that display abrupt or gradual interfaces between zones. From internal to external parts, these zones consist mainly of the following mineral associations and assemblages: (1) enargite ± (luzonite, pyrite, colusite, tennantite, goldfieldite, ferberite, gold-silver tellurides, bismuthinite, gold, alunite,...

Zoned Base Metal Mineralization in a Porphyry System: Origin and Evolution of Mineralizing Fluids in the Morococha District, Peru

“…These values coincide with fluid inclusion data from base metal mineralization from similar mining districts. These usually have salinities between 1 and 5 wt % NaCl equiv, but can reach intermediate compositions of 5 to 23 wt% NaCl equiv and salinities of >30 wt % NaCl equiv (Rye and Sawkins, 1974;Campbell et al, 1984;Hildreth and Hannah, 1996;Hedenquist et al, 1998;Beuchat et al, 2004;Simmons et al, 2005;Baumgartner et al, 2008;Rusk et al, 2008a;Bendezú and Fontboté, 2009). Magmatic fluid-derived base metal sulfides from such deposits are classically interpreted to have precipitated from magmatic brines diluted by meteoric waters (Landis and Rye, 1974;Kamilli and Ohmoto, 1977;John, 1989;Simmons, 1991;Deen et al, 1994;Bendezú and Fontboté, 2009) or directly from small amounts of magmatic brine (Wilkinson et al, 2013).…”

Mineralogy, Fluid Inclusions, and Sulfur Isotopes of the Huanzala Deposits, Peru: Early Skarn and Late Polymetallic Replacement Style Mineralizations

“…The general model of the ore-forming process and fluid evolutionary pathways for the Huanzala deposits may be applicable to other porphyry-related polymetallic deposits that have similar characteristics in mineral paragenesis and mineralizing fluids. A few examples are Cerro de Pasco (Baumgartner et al, 2008;Rottier et al, 2016), Colquijirca (Bendezú & Fontboté, 2009), Morococha (Catchpole et al, 2015), and other deposits in the Peruvian Andes metallogenic belt. Furthermore, magmatic-hydrothermal polymetallic veins, carbonate replacements, and skarn can also be included in the model.…”

“…Mineralization of this type forms typical ore deposits that have also been referred to as Butte‐type veins (Meyer et al, ), polymetallic veins, zoned base metal veins (Einaudi et al, ), and Cordilleran polymetallic veins or replacements (Bendezú et al, ). These deposits share the following major features (Bendezú & Fontboté, ): (i) they contain a polymetallic (Cu–Zn–Pb–Ag–Au) suite; (ii) their zones span from inner Cu‐bearing to outer Zn–Pb‐bearing ores; (iii) they have a sulfide‐rich character, commonly massive in texture; (iv) they primarily occur as open‐space fillings (veins, breccia bodies) in silicate host rocks and as replacements in carbonate rocks; and (v) they are mainly located at shallower levels than porphyry Cu–(Au–Mo) and skarn mineralization centers. Although these features imply a spatiotemporal relationship between early porphyry–skarn and late polymetallic orebodies within a single porphyry‐centered hydrothermal system, factors of the transition between these mineralization styles remain unclear (Sillitoe, ).…”

“…Mineralization of this type forms typical ore deposits that have also been referred to as Butte-type veins (Meyer et al, 1968), polymetallic veins, zoned base metal veins (Einaudi et al, 2003), and Cordilleran polymetallic veins or replacements (Bendezú et al, 2008). These deposits share the following major features (Bendezú & Fontboté, 2009): (i) they contain a polymetallic (Cu-Zn-Pb-Ag-Au) suite; (ii) their zones span from inner Cu-bearing to outer Zn-Pb-bearing ores;…”

Physiographic and tectonic settings of high-sulfidation epithermal gold–silver deposits of the Andes and their controls on mineralizing processes

“…This segment includes the cordilleran base metal lode deposits (i.e. sulfide rich polymetallic deposits: Bendezú et al, 2003) of Marcapunta-Colquijirca and Cerro de Pasco which are centered on high-sulfidation epithermal deposits emplaced in reactive host rocks (Bendezú and Fontboté, 2009;Bendezú et al, 2008). The northwestern metallogenetic belt has its southern terminus at Pierina at 9.5°Lat S, west of the Cordillera Blanca and is dominated by high-sulfidation epithermal and porphyry Cu-Au deposits but also includes a number of smaller vein hosted Ag-Au deposits such as Quiruvilca (Gustafson et al, 2004;Noble and McKee, 1999).…”