Abstract

ZAPATA G., GILBERTO  and  RODRIGUEZ G., GABRIEL. BASALTO DE EL BOTÓN, MIOCENE VOLCANIC ARC OF SHOSHONITIC AFFINITY TO THE NORTH OF CORDILLERA OCCIDENTAL OF COLOMBIA. Bol. cienc. tierra [online]. 2011, n.30, pp.77-92. ISSN 0120-3630.

Basalto de El Botón outcrops on the western flank of the mountainous chain 'Cordillera Occidental' as a block in north-south direction extending from Dabeiba's northwest and continuing until Frontino's southwest. It is a lithostratigraphic unit composed by porphyritic basalts and andesites, and a small amount of pyroclastic rocks and tectonic limited by the faults: Dabeiba -Pueblo Rico and La Cerrazón - Murri.. Basalto de El Botón is formed in a volcanic arc environment. It is composed by stocks such as Nudillales Monzonite, Carauta Monzodiorite, Jengamecodá Andesite and Cuarzodiorite from El Valle de Pérdida. All of them are the plutonic part of the magmatic arc which forms part of the basalt. Basalto de El Botón's rocks and its associated plutons are enriched in light rare earth elements and depleted in heavy rare earth. Its elements are from shoshonític character and have a kinship with volcanic arc environments. The ages obtained from basaltic rocks of El Botón and associated intrusive bodies indicate that the arc was formed between 9 Million of years and 12 million of years ago, in the Late Miocene (Tortonian) age.

Keywords : Basalto de El Botón; Cordillera Occidental of Colombia; shoshonite; Dabeiba; Antioquia; Colombia.

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