Revista De La Asociacion Geologica Argentina, Sep 1, 2008
... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del ... more ... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del área y creó el término Formación Negro Peinado para designar a "ectinitas, esquistos, pizarras ... Figura 9: a) Cumbre del cerro Negro Overo en el que la Formación Achavil aparece ...
We present mineralogic, isotopic and thermochronologic analyses on psammopelitic and tuffaceous l... more We present mineralogic, isotopic and thermochronologic analyses on psammopelitic and tuffaceous levels from the Bermejo and Vinchina basins – both foreland depocentres of the Central Andes of Argentina – that define a low-temperature regime for the crust akin to a slab shallowing and flattening process. The contents of illite in illite/smectite interstratified (I/S) show a progressive illitization into the deeper parts of both basins.
ABSTRACT. The metamorphic PT conditions of low-grade units from the Famatina belt, Central Andes ... more ABSTRACT. The metamorphic PT conditions of low-grade units from the Famatina belt, Central Andes of Argentina, were estimated through petrography, X-ray diffraction, and electron microscopy. For the Middle-Upper Cambrian Negro Peinado Formation a tectono ...
... Gilda Collo 1 , Ricardo A. Astini 1 , Agustín Cardona 2 , Margarita D. Do Campo 3 , Umberto C... more ... Gilda Collo 1 , Ricardo A. Astini 1 , Agustín Cardona 2 , Margarita D. Do Campo 3 , Umberto Cordani 4. ... consecuencia de la deformación, presencia de fluidos, variaciones en la composición de los minerales, el tamaño de grano, y las tasas de enfriamiento (Dahl, 1996; Villa ...
Page 1. Transformación progresiva de minerales de arcilla durante el soterramiento de la cuenca d... more Page 1. Transformación progresiva de minerales de arcilla durante el soterramiento de la cuenca de Vinchina (Mioceno Tardío-Plioceno), Sierras de los Colorados, La Rioja Julieta Nóbile, Gilda Collo y Federico M. Dávila Laboratorio ...
7th International Symposium on Andean Geodynamics (ISAG 2008, Nice), Extended Abstracts: 60-63 ..... more 7th International Symposium on Andean Geodynamics (ISAG 2008, Nice), Extended Abstracts: 60-63 ... Continental growth through protracted subduction and accretionary processes along Western Gondwana: The case of the Ocloyic Orogeny in southern South America
... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del ... more ... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del área y creó el término Formación Negro Peinado para designar a "ectinitas, esquistos, pizarras ... Figura 9: a) Cumbre del cerro Negro Overo en el que la Formación Achavil aparece ...
The Famatina belt, Central Andes, is part of an ancient accretionary margin built along Western G... more The Famatina belt, Central Andes, is part of an ancient accretionary margin built along Western Gondwana in the early Palaeozoic. UPb ion microprobe analysis of detrital zircons and SmNd whole-rock analysis of two early Palaeozoic low-grade metasedimentary units ...
Page 1. Historia posdeposicional de la Formación La Aguadita, Famatina, Argentina 283 Caracteriza... more Page 1. Historia posdeposicional de la Formación La Aguadita, Famatina, Argentina 283 Caracterización mineralógica, microestructural e historia posdeposicional de la Formación La Aguadita, Sistema de Famatina, La Rioja, Argentina ...
ABSTRACT A 44 m-thick lacustrine succession of silty-clay banded ochres and subordinated sandston... more ABSTRACT A 44 m-thick lacustrine succession of silty-clay banded ochres and subordinated sandstones, and conglomerates (known as the Corral Amarillo Formation) is superbly exposed within the Famatina Belt (Central Andes of Argentina) after deep entrenchment by the present-day Amarillo river due to strong recent uplifting and consequent relative drop in base level. The unusual ochreous-rich succession was produced by natural damming (3.48–3.54 14C kyr BP) of an acid drainage system linked to the alteration cap of polymetallic deposits. Facies of silty-clay ochre (wet season) and banded ochre (dry season) from the paleolacustrine setting are composed of jarosite+goethite and goethite respectively. Geochemically, these layers record high concentrations of Fe2O3 (25–55 wt. %) and trace elements (Cu, Zn, Co, As, and Mo with mean concentrations of 2,759; 2,467; 109; 375 and 116 ppm, respectively). Their origin is inferred from a comparative analysis with the present-day Amarillo river, which has a pH of ∼3, (SO4)2- concentrations of ∼5,000 mg/l, and jarosite as the dominant phase, in the upper catchments. Waters downstream have pH values of 3–4.5, (SO4)2- concentrations of ∼3,000–480 mg/l, and schwertmannite as the dominant phase. Thus goethite in the paleolake facies is likely related to schwertmannite transformation by an aging process, whereas jarosite is probably transported from the river but could also be associated with post-depositional formation regulated by variations in grain size and the pore fluid chemistry. The Corral Amarillo Formation offers a Natural model, which may be employed to infer the effect on nature of acid drainage of mineralized areas.
Revista De La Asociacion Geologica Argentina, Sep 1, 2008
... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del ... more ... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del área y creó el término Formación Negro Peinado para designar a "ectinitas, esquistos, pizarras ... Figura 9: a) Cumbre del cerro Negro Overo en el que la Formación Achavil aparece ...
We present mineralogic, isotopic and thermochronologic analyses on psammopelitic and tuffaceous l... more We present mineralogic, isotopic and thermochronologic analyses on psammopelitic and tuffaceous levels from the Bermejo and Vinchina basins – both foreland depocentres of the Central Andes of Argentina – that define a low-temperature regime for the crust akin to a slab shallowing and flattening process. The contents of illite in illite/smectite interstratified (I/S) show a progressive illitization into the deeper parts of both basins.
ABSTRACT. The metamorphic PT conditions of low-grade units from the Famatina belt, Central Andes ... more ABSTRACT. The metamorphic PT conditions of low-grade units from the Famatina belt, Central Andes of Argentina, were estimated through petrography, X-ray diffraction, and electron microscopy. For the Middle-Upper Cambrian Negro Peinado Formation a tectono ...
... Gilda Collo 1 , Ricardo A. Astini 1 , Agustín Cardona 2 , Margarita D. Do Campo 3 , Umberto C... more ... Gilda Collo 1 , Ricardo A. Astini 1 , Agustín Cardona 2 , Margarita D. Do Campo 3 , Umberto Cordani 4. ... consecuencia de la deformación, presencia de fluidos, variaciones en la composición de los minerales, el tamaño de grano, y las tasas de enfriamiento (Dahl, 1996; Villa ...
Page 1. Transformación progresiva de minerales de arcilla durante el soterramiento de la cuenca d... more Page 1. Transformación progresiva de minerales de arcilla durante el soterramiento de la cuenca de Vinchina (Mioceno Tardío-Plioceno), Sierras de los Colorados, La Rioja Julieta Nóbile, Gilda Collo y Federico M. Dávila Laboratorio ...
7th International Symposium on Andean Geodynamics (ISAG 2008, Nice), Extended Abstracts: 60-63 ..... more 7th International Symposium on Andean Geodynamics (ISAG 2008, Nice), Extended Abstracts: 60-63 ... Continental growth through protracted subduction and accretionary processes along Western Gondwana: The case of the Ocloyic Orogeny in southern South America
... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del ... more ... Fue Turner (1960) quien realizó los aportes más significativos al conocimiento geológico del área y creó el término Formación Negro Peinado para designar a "ectinitas, esquistos, pizarras ... Figura 9: a) Cumbre del cerro Negro Overo en el que la Formación Achavil aparece ...
The Famatina belt, Central Andes, is part of an ancient accretionary margin built along Western G... more The Famatina belt, Central Andes, is part of an ancient accretionary margin built along Western Gondwana in the early Palaeozoic. UPb ion microprobe analysis of detrital zircons and SmNd whole-rock analysis of two early Palaeozoic low-grade metasedimentary units ...
Page 1. Historia posdeposicional de la Formación La Aguadita, Famatina, Argentina 283 Caracteriza... more Page 1. Historia posdeposicional de la Formación La Aguadita, Famatina, Argentina 283 Caracterización mineralógica, microestructural e historia posdeposicional de la Formación La Aguadita, Sistema de Famatina, La Rioja, Argentina ...
ABSTRACT A 44 m-thick lacustrine succession of silty-clay banded ochres and subordinated sandston... more ABSTRACT A 44 m-thick lacustrine succession of silty-clay banded ochres and subordinated sandstones, and conglomerates (known as the Corral Amarillo Formation) is superbly exposed within the Famatina Belt (Central Andes of Argentina) after deep entrenchment by the present-day Amarillo river due to strong recent uplifting and consequent relative drop in base level. The unusual ochreous-rich succession was produced by natural damming (3.48–3.54 14C kyr BP) of an acid drainage system linked to the alteration cap of polymetallic deposits. Facies of silty-clay ochre (wet season) and banded ochre (dry season) from the paleolacustrine setting are composed of jarosite+goethite and goethite respectively. Geochemically, these layers record high concentrations of Fe2O3 (25–55 wt. %) and trace elements (Cu, Zn, Co, As, and Mo with mean concentrations of 2,759; 2,467; 109; 375 and 116 ppm, respectively). Their origin is inferred from a comparative analysis with the present-day Amarillo river, which has a pH of ∼3, (SO4)2- concentrations of ∼5,000 mg/l, and jarosite as the dominant phase, in the upper catchments. Waters downstream have pH values of 3–4.5, (SO4)2- concentrations of ∼3,000–480 mg/l, and schwertmannite as the dominant phase. Thus goethite in the paleolake facies is likely related to schwertmannite transformation by an aging process, whereas jarosite is probably transported from the river but could also be associated with post-depositional formation regulated by variations in grain size and the pore fluid chemistry. The Corral Amarillo Formation offers a Natural model, which may be employed to infer the effect on nature of acid drainage of mineralized areas.
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