Oro aluvial y asociación mineral de la cuenca hidrográfica del Río Umbe, cantón Quinsaloma, provincia de Los Ríos
Fecha
2023
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
La investigación consistió en establecer la presencia de oro aluvial en la cuenca hidrográfica del río Umbe, cantón Quinsaloma, provincia de Los Ríos. Se realizó un reconocimiento geológico-geomorfológico y se tomaron 20 muestras de material areno-gravoso, que fue lavado y concentrado mediante bateo. Luego del secado, pesaje y la separación magnética se identificaron los minerales mediante el estereoscopio binocular. Se determinaron parámetros morfométricos del oro tales como diámetro equivalente (Deq), índice de aplastamiento (IA) e índice de esfericidad (S). Se detectaron 17 partículas de oro, distribuidas mayormente en la llanura de inundación y terrazas aluviales, muy aplastadas y finas, tipo “polvo de oro” (< 0,27 mm); tienen textura rugosa y forma elipsoidal, en menor medida discoidal. Mediante análisis minerográfico (3 briquetas) se identificaron minerales metálicos como magnetita, ilmenita, hematita, esfena y trazas de sulfuros (pirita), además de translúcidos como zircón, epidota y hornblenda. La asociación mineralógica observada representa las ocurrencias minerales del terreno Macuchi: epitermales, VMS y pórfidos. Se propone un área potencial para trabajos geoquímicos detallados alrededor de la muestra TIC-BT011, y aguas arriba de la misma.
The investigation established the presence of alluvial gold in the hydrographic basin of the Umbe River, Quinsaloma Canton, Los Ríos Province. A geological-geomorphological reconnaissance was carried out and 20 samples of sandy-gravel material were taken, which were washed and concentrated by batting. After drying, weighing and magnetic separation, the minerals were identified using a binocular stereoscope. Gold morphometric parameters such as equivalent diameter (Deq), flattening index (IA), and sphericity index (S) were determined. Seventeen gold particles were detected, primarily distributed in the floodplain and alluvial terraces, very flattened and fine, "gold dust" type (< 0.27 mm); they have a rough texture and an ellipsoidal shape, to a lesser extent discoidal. Through minerographic analysis (3 briquettes), metallic minerals were identified such as magnetite, ilmenite, hematite, sphene, and traces of sulfides (pyrite), as well as translucent minerals like zircon, epidote, and hornblende. The observed mineralogical association represents the mineral occurrences of the Macuchi terrane: epithermal, VMS, and porphyry. A potential area for detailed geochemical work is proposed around and upstream of the TIC-BT011 sample.
The investigation established the presence of alluvial gold in the hydrographic basin of the Umbe River, Quinsaloma Canton, Los Ríos Province. A geological-geomorphological reconnaissance was carried out and 20 samples of sandy-gravel material were taken, which were washed and concentrated by batting. After drying, weighing and magnetic separation, the minerals were identified using a binocular stereoscope. Gold morphometric parameters such as equivalent diameter (Deq), flattening index (IA), and sphericity index (S) were determined. Seventeen gold particles were detected, primarily distributed in the floodplain and alluvial terraces, very flattened and fine, "gold dust" type (< 0.27 mm); they have a rough texture and an ellipsoidal shape, to a lesser extent discoidal. Through minerographic analysis (3 briquettes), metallic minerals were identified such as magnetite, ilmenite, hematite, sphene, and traces of sulfides (pyrite), as well as translucent minerals like zircon, epidote, and hornblende. The observed mineralogical association represents the mineral occurrences of the Macuchi terrane: epithermal, VMS, and porphyry. A potential area for detailed geochemical work is proposed around and upstream of the TIC-BT011 sample.
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Palabras clave
ORO ALUVIAL, CONCENTRADOS PESADOS, ANÁLISIS MINEROGRÁFICO, PARÁMETROS MORFOMÉTRICOS, CUENCA HIDROGRÁFICA