CONSIDERACIONES PETROGENÉTICAS Y GEOCRONOLOGÍA DE LAS ROCAS ÍGNEAS PORFIRÍTICAS AFLORANTES EN LA QUEBRADA VENTANAS (MUNICIPIO ARBOLEDAS, NORTE DE SANTANDER, COLOMBIA): IMPLICACIONES METALOGENÉTICAS
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Universidad Industrial de Santander
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En el sector de la quebrada Ventanas (sector suroccidental del municipio Arboledas; Norte de Santander), se reconoce la presencia de rocas ígneas porfiríticas de composición riodacítica, las cuales fueron datadas por U-Pb en circones mediante el método de LA-ICP-MS (Laser Ablation – Inductively Coupled Plasma –Mass Spectrometry), arrojando una edad de 13.9±0.2 Ma (Langhian; Mioceno, Neógeno). Los datos petrográficos y geoquímicos de éstas rocas, indican que éstas se formaron en un contexto de subducción, en ambientes de arco magmático de margen continental. Las altas relaciones Sr/Y (entre ~44.0 y 94.3) y la ausencia de anomalía negativa en Eu en éstas rocas, apuntan a que éstos magmas debieron tener un alto contenido de volátiles y por lo tanto pueden tener un alto potencial para formar mineralizaciones de tipo pórfido de Cu-Au-Mo. Considerando que el magmatismo del Neógeno se manifiesta igualmente en el Distrito Minero de Vetas y California (unos 40 km al SW del área de estudio); en donde ha sido relacionado con procesos de interés metalogénico; es posible suponer que el emplazamiento de estos magmas debió haber sido facilitado por la alta permeabilidad cortical generada por algunas fallas de dirección NE que afectan al Macizo de Santander (por ejemplo: Suratá-Arboledas y Cucutilla). Por consiguiente, las áreas localizadas a lo largo de estas estructuras pueden tener un gran interés para la exploración de depósitos minerales relacionados con procesos magmático-hidrotermales.
Around the Ventanas creek (southwestern sector of the Arboledas town, North Santander), porphyritic igneous rocks of rhyodacitic composition have been recognized and dated by zircon U-Pb methods using LA-ICP-MS (Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry) yielding an age of 13.9 ± 0.2 Ma (Langhian; Miocene, Neogene). Petrographic and geochemical data obtained from these rocks indicate that their origin is likely subduction-related, and that they were emplaced in a continental magmatic arc context. The high Sr/Y values (between ~ 44.0 and 94.3) and the absence of marked negative Eu anomalies suggest that the related magmas had high volatile contents, and therefore may have a high potential to form Cu-Au-Mo porphyry mineralization. Considering that the Neogene magmatism has been also reported in the California-Vetas Mining District (located ~40 km to SW of the studied area), where it is known to be related to metallogenic processes, we infer that the magma emplacement could have been facilitated by the high crust permeability generated by NE-trending faults affecting the Santander Massif (e.g. Arboledas-Suratá and Cucutilla faults). Therefore, other areas located along these structures can be considered of great interest for mineral exploration because of the related magmatic-hydrothermal processes.
Around the Ventanas creek (southwestern sector of the Arboledas town, North Santander), porphyritic igneous rocks of rhyodacitic composition have been recognized and dated by zircon U-Pb methods using LA-ICP-MS (Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry) yielding an age of 13.9 ± 0.2 Ma (Langhian; Miocene, Neogene). Petrographic and geochemical data obtained from these rocks indicate that their origin is likely subduction-related, and that they were emplaced in a continental magmatic arc context. The high Sr/Y values (between ~ 44.0 and 94.3) and the absence of marked negative Eu anomalies suggest that the related magmas had high volatile contents, and therefore may have a high potential to form Cu-Au-Mo porphyry mineralization. Considering that the Neogene magmatism has been also reported in the California-Vetas Mining District (located ~40 km to SW of the studied area), where it is known to be related to metallogenic processes, we infer that the magma emplacement could have been facilitated by the high crust permeability generated by NE-trending faults affecting the Santander Massif (e.g. Arboledas-Suratá and Cucutilla faults). Therefore, other areas located along these structures can be considered of great interest for mineral exploration because of the related magmatic-hydrothermal processes.
Keywords
Ventanas Creek, Arboledas, Neogene, Metallogeny, Santander Massif, Colombia, Quebrada Ventanas, Arboledas, Neógeno, Metalogenia, Macizo de Santander, Colombia