Citas bibligráficas
Vila, Ñ., (2021). Distribución mineralógica y composicional en las vetas cordilleranas de Zn-Pb-Ag-Cu en el distrito de San Cristóbal, Domo de Yauli, Perú Central [Tesis, Universidad Nacional de Ingeniería]. http://hdl.handle.net/20.500.14076/22114
Vila, Ñ., Distribución mineralógica y composicional en las vetas cordilleranas de Zn-Pb-Ag-Cu en el distrito de San Cristóbal, Domo de Yauli, Perú Central [Tesis]. PE: Universidad Nacional de Ingeniería; 2021. http://hdl.handle.net/20.500.14076/22114
@misc{renati/267193,
title = "Distribución mineralógica y composicional en las vetas cordilleranas de Zn-Pb-Ag-Cu en el distrito de San Cristóbal, Domo de Yauli, Perú Central",
author = "Vila Godoy, Ñieriton Arquimedes",
publisher = "Universidad Nacional de Ingeniería",
year = "2021"
}
The San Cristóbal district is located in the western part of the Yauli Dome. It hosts cordilleran deposits, in the form of veins and replacement bodies, of which the San Cristóbal, Andaychagua and Prosperidad veins and the Brecha Recuay and San Cristóbal Este prospects, are part of this study. The district shows a marked metal zonation, which is defined by a central part of W, followed by a zone of Cu, an intermediate zone of Zn-Pb-(Ag) and an external zone of Ag-Pb-(Zn). Three stages in the paragenesis have been recognized in these zones: (1) quartz-pyrite-wolframite stage, it is the earliest and also is composed of specularite, chalcopyrite, scheelite, emplectite, muscovite, illite, chalcedony; (2) base metal stage, it is the most economical and composed of sphalerite (dark to light brown), chalcopyrite, galena ± (fahlore, pyrite, arsenopyrite, pyrrhotite, illite, acanthite); (3) carbonate stage, it is the latest and is divided into two sub-stages: Sub-stage manganosiderite-rhodochrosite, with barite, quartz, arsenopyrite ± (pyrite, sphalerite reddish, galena, red silver, chalcopyrite, marcasite, stibnite, illite, dickite). Ankerite-dolomite sub-stage, the most distal, with jasperoids, barite, chalcedony, quartz, calcite ± (dickite, specularite and chlorite). Isovalues in the longitudinal sections of the Andaychagua and Prosperidad veins illustrate that Cu values >1 % are found in depth, Zn >7 % and Pb >1 % in the intermediate parts and Ag >7 Oz/t in the intermediate and upper parts. Zn/Pb ratios indicate possible directions of flow of the hydrothermal fluid from southwest to northeast. Isovalues in the San Cristóbal vein, show the coexistence of high concentrations of Ag, Zn, Pb, Cu and WO3. Changes in sulfide assemblages are accompanied by variations in % Fe in sphalerites, from 9.84 % in the Cu zone to 0.42 % in the Zn-Pb-(Ag) and Ag-Pb-(Zn) zone. These variations of % Fe in sphalerite are typical of low to intermediate sulphidation cordilleran veins. Furthermore, assemblages of sericitic alteration (muscovite, illite, quartz and dickite) and remobilization of elements (Al, K, Ca, Sr, Ba and Rb) show the hydrothermal fluid was moderately acidic. X-ray fluorescence microanalysis on ankerites and dolomites from Brecha Recuay, exhibiting zones with MnO contents >2 %, which typically occur between 200 and 300 m above the polymetallic mineralization in veins. Fluid inclusions in quartz from the quartz-pyrite-wolframite stage are biphasic (LV) and homogenize to the liquid phase, between 180.3 °C and 327 °C, with salinities between 1.74 and 6.45 wt % NaCl equiv. Sporadic triphasic inclusions with salt crystals show salinities of up to 43.46 wt % NaCl equiv. Fluid inclusions in quartz, sphalerite, manganosiderite and calcite from the base metals and carbonate stage, show homogenization temperatures ranging between 163.2 °C and 281.8 °C and salinities between 1.40 and 5.86 wt % NaCl equiv. This reveals an epithermal formation environment with high and low salinities, where metal zoning is marked by temperature gradients (~100 °C through paragenesis).
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