Reconnaissance of the Tetrahedrite-Tennantite/Enargite-Famatinite Phase Relations as a Possible Geothermometer

Feiss, P. Geoffrey

doi:10.2113/gsecongeo.69.3.383

Cited by 11 publications

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“…On the other hand, the Ag/Cu ratio remains essentially constant because most of the silver and copper are in tennantite-tetrahedrite. , The pyritic enargite-tennantite/tetrahedrite-barite ores studied by Feiss (1970Feiss ( , 1974 extend to about the Pb/Cu --1 contour in Figure 10. The temperature of deposition of these ores is inferred to have been between 350øC and 300øC on the basis of preliminary fluid inclusion filling temperature measurements (G. Salazar, pers.…”

Section: Cu Pb Cumentioning

confidence: 91%

“…commun.) on the basis of sulfur isotopic partitioning between pairs of sulfates and sulfides (Goodell, 1970) and on the basis of partitioning of As and Sb between enargite-famatinire and tennantite-tetrahedrite (Feiss, 1970). These studies revealed no significant telnperature gradient along the presumed hydrothermal solution paths.…”

Section: Cu Pb Cumentioning

confidence: 99%

“…DURING the past decade the Julcani mining district has been the object of a large number of geological studies by resident geologists, consultants, and scientific investigators (see, for instance, Goodell and Petersen, 1974;Feiss, 1974). As a consequence, it has become one of the best known Peruvian mineral districts.…”

Section: Introductionmentioning

confidence: 99%

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Geology of the Julcani mining district, Peru

Petersen¹,

Noble²,

Arenas³

et al. 1977

Economic Geology

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Zoned, polymetallic base and precious metal (Ag-Bi-Pb-Cu-W-Au) mineralization at the Julcani district, central Peru, is genetically related to a geologically brief pulse of late Miocene (•10 m.y.) calc-alkalic magmatic activity. The Julcani volcanic center appears to have been localized by an anticlinal flexure in Paleozoic and Mesozoic strata, and perhaps by longitudinal and/or transverse faults. Early eruption of voluminous pyroclastic material was succeeded by the eraplacement of interpenetrating volcanic domes of dacitic to rhyodacitic composition. Hydrothermal alteration and mineralization took place concurrently with the intrusion of late-stage volcanic domes and dikes. Complex systems of fractures and faults that channeled hydrothermal solutions and localized the various late-stage dikes were produced by repeated pulses of magmatic doming, perhaps aided by renewed movement along regional faults.Mineralization is almost exclusively confined to fracture fillings, with only subordinate replacement of sheared country rocks within the vein structure. Ore solutions spread upward and laterally from several centers, producing clearly defined zoning patterns. Three of these hydrothermal systems (Herminia, Mimosa, and Estela) have now been studied mineralogically and analyzed by detailed metal ratio contouring. The central part of the district, characterized by the pyritic gold-tungsten mineralization of Tentadora, appears to be the innermost zone of the Herminia system. Solutions moving southeast from Tentadora split, with a portion moving north into the Lucrecia vein system, a portion continuing southeast along the Docenita vein (which fed the veins in the old Herminia and Santo Domingo-San Jos• mines), and much of the remainder flowing south along Luz-82 vein and then east and west along the Afio-2NW vein system. Along these paths they deposited first enargite-pyrite-tennantite/tetrahedrite, then a zone of complex silver and bismuth-sulfosalts with bismuthinite, and at greater distances galena followed by lead sulfosalts, orpiment, and realgar. In the Mimosa vein system, tennantite/ tetrahedrite predominates in the lower or inner zones and galena in the outer zones; the antimony and silver content of tennantite/tetrahedrite increases systematically upward along the solution paths. In Estela, early pyrite-wolframite mineralization is followed first by tennantite/tetrahedrite-chalcopyrite-arsenopyrite-bismuthinite and then by galenasphalerite mineralization. The zone of pyritic gold-tungsten mineralization, which corresponds approximately with a zone of premineral dikes of intrusive breccia and tuffisite and with the inferred location of the vent for the early pyroclastic rocks, overlies the permeable rock through which a large portion of the mineralizing solutions ascended. Detailed metal-ratio zoning studies have helped considerably in guiding exploration and development of Julcani, alloxving a marked increase in ore reserves, as well as the estimation of larger amounts of prospective ore than xvas heretofore pos...

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Section: Cu Pb Cumentioning

confidence: 91%

Section: Cu Pb Cumentioning

confidence: 99%

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Geology of the Julcani mining district, Peru

Petersen¹,

Noble²,

Arenas³

et al. 1977

Economic Geology

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“…In the central enargite zone, abundant enargite-luzonite intergrowths of the early base metal stage (C. R. Patri, 1961, unpub. data) indicate a temperature of formation in the region of 300 ø to 320øC, which is the lower stability temperature range of enargite (Maske and Skinner, 1971;Feiss, 1974). The presence of enargite and mately 16 cm.…”

Section: Interpretation Of the Space-time Evolution Of Alteration Andmentioning

confidence: 93%

Quiruvilca, Peru; mineral zoning and timing of wall-rock alteration relative to Cu-Pb-Zn-Ag vein-fill deposition

Bartos¹

1987

Economic Geology

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Quiruvilca district Cu-Pb-Zn-Ag veins have produced over 8 million tons of ore since 1789. The veins occupy tension gashes associated with left-lateral strike-slip faults that cut the central facies of a Miocene andesitic stratovolcano complex. The district has four broadly concentric mineralogic zones from district center to edges which are based on dominant vein fill: enargite, transition, lead-zinc, and stibnite. All veins, regardless of zonal position in the district, share the same four gross paragenetic stages: pyrite, base metal, sulfosalt, and carbonate. Veins closest to the center of the district contain relatively greater proportions of the earlier assemblages. Mineralogic zoning commonly is focused on vein intersections and on a local scale reflects changes in vein width.Wall-rock alteration types from the vein margin outward and from most intense to least intense are intense sericitic, strong sericitic, moderate sericitic, strong argillic, weak argillic, and propylitic. Petrographic observations indicate that at any given location, propylitic alteration is oldest, followed by argillic, and then sericitic alteration. The zoned alteration halos formed as each inner assemblage advanced, overprinted, and replaced its adjacent outer precedent. The width and intensity of alteration halos enclosing veins increase with depth and toward the district center.Correlation between paragenetic stages of vein fill and wall-rock alteration is based upon the mineralogy and wall-rock alteration of single-stage veinlets that are zoned about major veins. The veinlet sequence in time correlates with the veinlet distribution in space; this also matches the time-space sequence documented for major veins. Most alteration occurred contemporaneously with the pyrite stage of mineralization. Ore deposition followed in the base metal stage. Thus, ore deposition in the veins in large part postdated formation of the alteration halos associated with those veins. This time sequence is corroborated by breccia dikes which cut alteration halos but precede the base metal stage.Temperatures of ore deposition, deduced from the stability of various mineral assemblages, decreased through time from •320 ø to <230øC. Fugacity of sulfur (rs2) decreased (from '• 10 -6 to <10 -12'5) both with time and laterally away from the district center. The pH is inferred to have increased laterally away from the center of the district and to have decreased in time at any one spot in the wall rock.

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“…A change in the ore-forming condition may therefore explain the As Sb zoning. Feiss (1974) noted in synthetic studies the rapid change from As-rich to Sb-rich members of the tetrahedrite-tennantite series in equilibrium with Simplified representation of the Bi2S 3-PbS-Cu2S-CuFeS2 system at 450 ~ E = emplectite; Ds~ = extension of the Cu3+xBi5 ~S 9 solid solution towards PbS; T = Cus.4Fe~.2Blo.sS22 (data from Sugaki andShima, 1978, andHarris andChen, 1976).…”

Section: The Tomnadashan Depositmentioning

confidence: 99%

Sulphide mineralogy of the Tomnadashan copper deposit and the Corrie Buie lead veins, south Loch Tayside, Scotland

Pattrick

1984

Mineral. mag.

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Copper mineralization at Tomnadashan is associated with granitic lenses intruded into a small Caledonian diorite body. The mineralization occurs as disseminations and irregular veinlets and mainly comprises pyrite, chalcopyrite, tetrahedrite-tennantite, calcite, and quartz. There are small inclusions of bismuthinite, galena, aikinite [(Cu,Pb,Fe,Bi)S3], and a mineral with a chemistry similar to hodrushite (Cu8Bi12S22). The tetrahedrite contains up to 6.1 wt. % bismuth.Four km to the south, at Corrie Buie, are quartz veins, hosted by meta-limestones, containing galena with minor amounts of chalcopyrite, pyrrhotite, sphalerite, electrum, schirmerite, and lillianite homologues.The mineralogy of both deposits is consistent with that associated with acid magmatism. There are mineralogical similarities between the two deposits but the style of mineralization at Tomnadashan suggests a limited hydrothermal system and therefore the Corrie Buie veins may be related to felsic intrusives to the south.

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Reconnaissance of the Tetrahedrite-Tennantite/Enargite-Famatinite Phase Relations as a Possible Geothermometer

Cited by 11 publications

References 0 publications

Geology of the Julcani mining district, Peru

Geology of the Julcani mining district, Peru

Quiruvilca, Peru; mineral zoning and timing of wall-rock alteration relative to Cu-Pb-Zn-Ag vein-fill deposition

Sulphide mineralogy of the Tomnadashan copper deposit and the Corrie Buie lead veins, south Loch Tayside, Scotland

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