Muestra la distribución de disciplinas para esta publicación.
Publicaciones WoS (Ediciones: ISSHP, ISTP, AHCI, SSCI, SCI), Scopus, SciELO Chile.
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| Año | 1998 | ||||
| Tipo | artículo de investigación |
Citas Totales
Autores Afiliación Chile
Instituciones Chile
% Participación
Internacional
Autores
Afiliación Extranjera
Instituciones
Extranjeras
Copper ore deposits with variable amounts of Ag, Au and Fe are hosted by La Negra Formation basaltic-andesites (ca. 180 Ma) and gabbroic to granitic plutonic rocks (160-140 Ma) that intrude them. The stratabound Cu+/-Ag ore deposits include stratiform and breccia pipe bodies which are mainly hosted by the volcanic rocks, whereas the Cu-Fe+/-Au (chalcopyrite-magnetite-actinolite) vein bodies are only found in the intrusives. The space and time relationships between both types of deposits suggest a common hydrothermal origin genetically related with the Middle-Upper Jurassic granitoids. This is consistent with the isotopic composition (delta(34)S(CDT)=3,5 to 2 parts per thousand; delta(13)C(PDB)=3,9 parts per thousand; delta(18)O(SMOW)=14 parts per thousand) of the ore/gangue minerals showing a magmatic origin for the hydrothermal solutions responsible for the ore deposits genesis. The initial Sr-87/Sr-86 ratio of the hydrothermal solutions (0,70435) has been inferred from the calcite isotopic composition in the gangue assemblage, and this value is slightly higher than the same ratio in genetically related granitoids (0,70329-0,70387). This difference suggests an interaction of magmatic derived solutions with fluids of higher Sr-87/Sr-86 initial ratio, e.g., meteoric dominated water isotopically equilibrated with older crustal rocks. The ore lead composition (Pb-206/Pb-204 18,529; Pb-207/Pb-204 15,630; Pb-208/Pb-204 38,526) shows a common orogenic reservoir for both type of deposits. The vein deposits were formed at the higher temperature plutonic environment by magmatic derived solutions at equilibria with magnetite and at a neutral to slightly alcaline pH, as it is shown by magnetite associated with ore minerals and albite or potassic feldspar alteration minerals. These hydrothermal fluids moved up to a near surface volcanic environment, characterized by lower temperatures and higher oxygen fugacity than the plutonic one with hematite stable, to form the stratabound ore deposits.
| Ord. | Autor | Género | Institución - País |
|---|---|---|---|
| 1 | Vivallo, Waldo | Hombre |
Servicio Nacional de Geología y Minería - Chile
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| 2 | HENRIQUEZ-BARRIENTOS, FERNANDO | Hombre |
Universidad de Santiago de Chile - Chile
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