Abstract
The Pocos de Caldas Alkaline Massif covers 800 km{sup 2}, a quarter of which is hydrothermally altered. Such proportion is uncommon, when compared to the know alkaline massifs of the world. The hydrothermal alteration is associated with Zr, U and Mo mineralizations which are predominantly located in the central-southern portion of the massif, in the central-eastern circular structure. The colour of the altered rock (and its soil) in that area is typically whitish beige to yellowish white and is regionally called potassic rock. The Osamu Utsumi Mine, also referred to as the uranium ore of Campo do Cercado, is located 25 Km to the south of Pocos de Caldas City and was explored, from 1977 to 1989, through the open pit method. A sequence of alteration minerals adapted to lowering temperatures should be expected; however, only illite and alkaline feldspar are observed in the hydrothermally altered portions of the massif, and their formation must have been controlled mainly by kinetic, other than thermal factors. The irrestrict circulation of relatively hotter hydrothermal fluids must have happened at the beginning of the process, diminishing immediately after the cooling of the brecciated areas (and the subjacent magmatic body), leading the system to kinetics
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Citation Formats
Garda, G M.
The hydrothermal alteration in the context of geologic evolution from Pocos de Caldas Alkaline Massif, MG-SP; A alteracao hidrotermal no contexto da evolucao geologica do Macico Alcalino de Pocos de Caldas, MG-SP.
Brazil: N. p.,
1990.
Web.
Garda, G M.
The hydrothermal alteration in the context of geologic evolution from Pocos de Caldas Alkaline Massif, MG-SP; A alteracao hidrotermal no contexto da evolucao geologica do Macico Alcalino de Pocos de Caldas, MG-SP.
Brazil.
Garda, G M.
1990.
"The hydrothermal alteration in the context of geologic evolution from Pocos de Caldas Alkaline Massif, MG-SP; A alteracao hidrotermal no contexto da evolucao geologica do Macico Alcalino de Pocos de Caldas, MG-SP."
Brazil.
@misc{etde_10157112,
title = {The hydrothermal alteration in the context of geologic evolution from Pocos de Caldas Alkaline Massif, MG-SP; A alteracao hidrotermal no contexto da evolucao geologica do Macico Alcalino de Pocos de Caldas, MG-SP}
author = {Garda, G M}
abstractNote = {The Pocos de Caldas Alkaline Massif covers 800 km{sup 2}, a quarter of which is hydrothermally altered. Such proportion is uncommon, when compared to the know alkaline massifs of the world. The hydrothermal alteration is associated with Zr, U and Mo mineralizations which are predominantly located in the central-southern portion of the massif, in the central-eastern circular structure. The colour of the altered rock (and its soil) in that area is typically whitish beige to yellowish white and is regionally called potassic rock. The Osamu Utsumi Mine, also referred to as the uranium ore of Campo do Cercado, is located 25 Km to the south of Pocos de Caldas City and was explored, from 1977 to 1989, through the open pit method. A sequence of alteration minerals adapted to lowering temperatures should be expected; however, only illite and alkaline feldspar are observed in the hydrothermally altered portions of the massif, and their formation must have been controlled mainly by kinetic, other than thermal factors. The irrestrict circulation of relatively hotter hydrothermal fluids must have happened at the beginning of the process, diminishing immediately after the cooling of the brecciated areas (and the subjacent magmatic body), leading the system to kinetics levels that made subsequent hydrothermal alteration impossible. (author).}
place = {Brazil}
year = {1990}
month = {Dec}
}
title = {The hydrothermal alteration in the context of geologic evolution from Pocos de Caldas Alkaline Massif, MG-SP; A alteracao hidrotermal no contexto da evolucao geologica do Macico Alcalino de Pocos de Caldas, MG-SP}
author = {Garda, G M}
abstractNote = {The Pocos de Caldas Alkaline Massif covers 800 km{sup 2}, a quarter of which is hydrothermally altered. Such proportion is uncommon, when compared to the know alkaline massifs of the world. The hydrothermal alteration is associated with Zr, U and Mo mineralizations which are predominantly located in the central-southern portion of the massif, in the central-eastern circular structure. The colour of the altered rock (and its soil) in that area is typically whitish beige to yellowish white and is regionally called potassic rock. The Osamu Utsumi Mine, also referred to as the uranium ore of Campo do Cercado, is located 25 Km to the south of Pocos de Caldas City and was explored, from 1977 to 1989, through the open pit method. A sequence of alteration minerals adapted to lowering temperatures should be expected; however, only illite and alkaline feldspar are observed in the hydrothermally altered portions of the massif, and their formation must have been controlled mainly by kinetic, other than thermal factors. The irrestrict circulation of relatively hotter hydrothermal fluids must have happened at the beginning of the process, diminishing immediately after the cooling of the brecciated areas (and the subjacent magmatic body), leading the system to kinetics levels that made subsequent hydrothermal alteration impossible. (author).}
place = {Brazil}
year = {1990}
month = {Dec}
}