INSUGEO   12554
INSTITUTO SUPERIOR DE CORRELACION GEOLOGICA
Unidad Ejecutora - UE
capítulos de libros
Título:
The Tajo Largo Gold Deposit, Argentina – Mineralogy and Fluid Inclusions Study.
Autor/es:
AVILA, JULIO; BENGOCHEA, LEANDRO; FOGLIATA, ANA; MAS, GRACIELA; LAZARTE JOSÉ
Libro:
Ninth Internacional Congress for Applied Mineralogy
Editorial:
The Australasian Institute of Mining and Metallurgy
Referencias:
Lugar: Carlton Victoria, Australia; Año: 2008; p. 589 - 592
Resumen:
Presentado en congreso y publicado en libro con ISBN por The Australasian Institute of Mining and Metallurgy he Culampajá auriferous district is located in the northern sector of the eastern edge of the homonymous hill, Catamarca Province, Argentina. Tajo Largo mine is situated in the southern flank of Las Minas gulch at an approximate height of 3.600 m above sea level. In the studied area main outcrops are orthogneiss rocks of Chango Real Formation. The ore mineral is native gold with a lesser amount of pyrite, chalcopyrite, haematite, limonite, malachite, azurite and covellite. These ore mineral assemblages are disseminated in quartz veins filling tension fractures in the host orthogneiss. Several types of inclusions have been recognised, including three phase H2O-CO2liq.-CO2vap. inclusions, polyphase inclusions with H2O-CO2 and one or more solid phases, and two phase aqueous inclusions. In the three phase H2O-CO2liq-CO2vap inclusions the Tmclath is about 1°C and the CO2 liquid-vapour homogenisation occurs at 26 - 28°C, to liquid phase. The homogenisation temperature of H2O-CO2 occurs at 365 - 380°C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equiv and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4°C and the eutectic point (Te) in -38°C indicates a salinity of about 7.5 wt per cent NaCl equiv., with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).2O-CO2liq.-CO2vap. inclusions, polyphase inclusions with H2O-CO2 and one or more solid phases, and two phase aqueous inclusions. In the three phase H2O-CO2liq-CO2vap inclusions the Tmclath is about 1°C and the CO2 liquid-vapour homogenisation occurs at 26 - 28°C, to liquid phase. The homogenisation temperature of H2O-CO2 occurs at 365 - 380°C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equiv and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4°C and the eutectic point (Te) in -38°C indicates a salinity of about 7.5 wt per cent NaCl equiv., with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).2O-CO2liq-CO2vap inclusions the Tmclath is about 1°C and the CO2 liquid-vapour homogenisation occurs at 26 - 28°C, to liquid phase. The homogenisation temperature of H2O-CO2 occurs at 365 - 380°C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equiv and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4°C and the eutectic point (Te) in -38°C indicates a salinity of about 7.5 wt per cent NaCl equiv., with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).2 liquid-vapour homogenisation occurs at 26 - 28°C, to liquid phase. The homogenisation temperature of H2O-CO2 occurs at 365 - 380°C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equiv and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4°C and the eutectic point (Te) in -38°C indicates a salinity of about 7.5 wt per cent NaCl equiv., with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).2O-CO2 occurs at 365 - 380°C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equiv and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4°C and the eutectic point (Te) in -38°C indicates a salinity of about 7.5 wt per cent NaCl equiv., with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4°C and the eutectic point (Te) in -38°C indicates a salinity of about 7.5 wt per cent NaCl equiv., with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).3. Homogenisation temperature ranges between 260° and 280°C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).