Boiling and vertical mineralization zoning: a case study from the Apacheta low-sulfidation epithermal gold-silver deposit, southern Peru

André-Mayer, Anne-Sylvie; Leroy, Jacques; Bailly, Laurent; Chauvet, Alain; Marcoux, Éric; Grancea, Luminita; Llosa, Fernando; Rosas, Juan Carlos

doi:10.1007/s00126-001-0247-2

Cited by 61 publications

(38 citation statements)

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“…The fluid inclusion data help in its identification (this work and André-Mayer et al 2002). The intervention of boiling may explain the relatively haphazard localization of the second-stage-related mineralization within the main earlier veins (Fig.…”

Section: The Shila-paula Mineralization Modelmentioning

confidence: 75%

“…However, the systematic open-style texture that characterizes stage 2, associated with the few indications of a boiling process, argues in favor of a significant participation of fluid overpressure during the stage 2 mineralization. A recent detailed analysis of the Apacheta fluid inclusions concluded that boiling has been associated with overpressure and subsequent rupture and hydrothermal brecciation (André-Mayer et al 2002). In fact, it is quite possible for tectonics and fluid overpressure to have functioned simultaneously.…”

Section: Regional Implicationsmentioning

confidence: 99%

“…Commonly characterized by the presence of welldeveloped mineralized veins (especially in the case of low-sulfidation deposits, e.g., Heald et al 1987;White and Hedenquist 1995), these systems provide favorable study sites for advancing our understanding of vein formation. Nevertheless, most studies devoted to this vein type have concentrated more directly on ore-forming factors such as: (1) the ore and alteration mineralogy, combined with chemical and textural aspects (e.g., Hayba et al 1985;Petersen et al 1990;Dong et al 1995;White and Hedenquist 1995); (2) physico-chemical and isotopic characterization of the involved hydrothermal fluids (e.g., Bodnar et al 1985;De Ronde and Blattner 1988;Moore et al 1992;Matsuhisa and Aoki 1994;Hayashi et al 2001); (3) the effects of boiling, mixing, and water/rock interaction on ore transport and deposition (e.g., Drummond and Ohmoto 1985;Reed and Spycher 1985;Cole and Drummond 1986); and (4) the lateral and vertical zoning of hydrothermal ore and gangue minerals (e.g., Cline et al 1992;Plumlee 1994;Cooke and McPhail 2001;André-Mayer et al 2002). Very few studies were focused on the geometric and textural aspects of mineralized epithermal veins in relation to the regional structural setting (e.g., Fletcher et al 1989;Naito 1993;Horner and Enriquez 1999;Ponce and Glen 2002).…”

Section: Introductionmentioning

confidence: 99%

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Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru

et al. 2006

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The epithermal Shila-Paula Au-Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E-W vein with secondary N55-60°W veins-two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartz-adulariapyrite-galena-sphalerite-chalcopyrite-electrum-Mn silicate-carbonate assemblage that fills the main E-W veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartz-adularia-carbonate assemblage that is observed within the secondary N45-60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings. The two latter structures are finally filled by the bonanza substage characterized by a Fe-poor sphalerite-chalcopyrite-pyrite-galena-tennantite-tetrahedrite-polybasite-pearceite-electrum assemblage. The ore in the main veins is systematically brecciated, whereas the ore in the secondary veins and geodes is characteristic of open-space crystallization. Microthermometric measurements on sphalerite from both stages and on quartz and calcite from stage 2 indicate a salinity range of 0 to 15.5 wt% NaCl equivalent and homogenization temperatures bracketed between 200 and 330°C. Secondary CO 2 -, N 2 -and H 2 S-bearing fluid inclusions are also identified. The age of vein emplacement, based on 40 Ar/ 39Ar ages obtained on adularia of different veins, is estimated at around 11 Ma, with some overlap between adularia of stage 1 (11.4±0.4 Ma) and of stage 2 (10.8±0.3 Ma). A three-phase tectonic model has been constructed to explain the vein formation. Phase 1 corresponds to the assumed development of E-W sinistral shear zones and associated N60°W cleavages under the effects of a NE-SW shortening direction that is recognized at Andean scale. These structures contain the stage 1 ore assemblage that was brecciated during ongoing deformation. Phase 2 is a reactivation of earlier structures under a NW-SE shortening direction that allowed the reopening of the preexisting schistosity and the formation of scarce N50°E-striking S2-cleavage planes filled by the stage 2 pre-bonanza minerals. Phase 3 coincides with the bonanza ore emplacement in the secondary N45-60°W veins and also in open-space in the core of the main E-W veins. Our combined tectonic, textural, mineralogical, fluid-inclusion, and geochronological study presents a complete model of vein formation in which the reactivation of previously formed tectonic structures plays a significant role in ore formation.

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Section: The Shila-paula Mineralization Modelmentioning

confidence: 75%

Section: Regional Implicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru

et al. 2006

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“…2A and B). The cause of adularia precipitation is the release of CO 2 during boiling, which causes a pH increase of the solution and, consequently, a shift to the adularia stability field from that of illite (e.g., André-Mayer et al, 2002;Browne, 1978;Browne and Ellis, 1970):…”

Section: Introductionmentioning

confidence: 99%

“…Boiling is the most important process triggering metal deposition in many ore deposit settings, in particular in epithermal systems (e.g., André-Mayer et al, 2002;Skinner, 1997). In the shallowest 2 km of the hydrothermal systems, boiling is the main process controlling the key chemical parameters for mineral precipitation such as pH, fluid composition and mineral solubility.…”

Section: Introductionmentioning

confidence: 99%

A model of boiling for fluid inclusion studies: Application to the Bolaños Ag–Au–Pb–Zn epithermal deposit, Western Mexico

Canet

Franco

Prol‐Ledesma

et al. 2011

Journal of Geochemical Exploration

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Metallogenesis of the Late Palaeozoic Axi–Tawuerbieke Au–Pb–Zn district in the Tulasu Basin, Western Tianshan, China: Constraints from geological characteristics and isotope geochemistry

Peng

Cheng

et al. 2018

Geological Journal

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The Tulasu Basin is an important epithermal gold ore cluster situated in the Boluokenu Polymetallic Belt, Western Tianshan, China. The Axi Au, Tabei Pb–Zn, and Tawuerbieke Au deposits in this basin represent different types of epithermal mineralization. These are products of the same tectonic‐magmatic‐hydrothermal event, related to the southward subduction of the North Tianshan Ocean beneath the Yili‐Central Tianshan Plate during the Late Devonian to Early Carboniferous. The spatial relationships, preservation levels, and evolution of the three deposits are still debated. Hence, systematic geological field investigations, ore microscopy, and isotopic analyses were carried out on these three deposits. The S–Pb–C–H–O isotopic compositions indicate that the ore‐forming components were derived from the volcanic‐subvolcanic rocks, as well as from circulating meteoric waters. The occurrence of adularia, silicified platy carbonates, and quartz characterized by crustiform/colloform/colloidal textures at Axi indicate that boiling was the main precipitation mechanism for the Au mineralization. The Pb–Zn ores from Tabei are characterized by abundant banded coarse‐grained quartz crystals with dog tooth and comb textures, suggesting that the sulphides precipitated slowly due to conductive cooling. The Tawuerbieke Au deposit is characterized by pervasive silicification and phyllic alteration accompanying veinlet and disseminated ore, which formed via metasomatic water–rock interaction. According to the ore textures, intrusion sizes, and mineral assemblages, it can be inferred that all three deposits experienced different extents of erosion (Axi < Tabei < Tawuerbieke) and that there is exploration potential for concealed porphyry Cu–Au mineralization. Exploration should focus on deep targets beneath the Tawuerbieke Au deposit.

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Boiling and vertical mineralization zoning: a case study from the Apacheta low-sulfidation epithermal gold-silver deposit, southern Peru

Cited by 61 publications

References 39 publications

Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru

Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru

A model of boiling for fluid inclusion studies: Application to the Bolaños Ag–Au–Pb–Zn epithermal deposit, Western Mexico

Metallogenesis of the Late Palaeozoic Axi–Tawuerbieke Au–Pb–Zn district in the Tulasu Basin, Western Tianshan, China: Constraints from geological characteristics and isotope geochemistry

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