Abstract

RODRIGUEZ-GARCIA, Gabriel et al. New ages, correlation and magmatic cycle of island arc plutons in the north of the Western Cordillera of Colombia. Bol. geol. [online]. 2023, vol.45, n.2, pp.15-33.  Epub June 15, 2023. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v45n2-2023001.

This paper presents new petrographic and U-Pb zircon geochronological data for plutonic bodies with island arc chemical affinity, located in the northeastern sector of the Western Cordillera of Colombia and composed by tonalites, quartz diorites, diorites, gabbros, plagiogranites and andesites from the Santa Fe de Antiquia Tonalite, Buriticá Tonalite, La Noque Tonalite and the Guarco Andesite, some of which contain mafic gabbro xenoliths and are cut by andesitic and basaltic dikes. These plutons yielded zircon U-Pb ages between 100.9 ± 0.85 Ma and 78.4 ± 6.4 and granofels that yielded crystallization ages between 91.6 ± 6.5 Ma and 84.71 ± 0.60 Ma, and is interpreted as the granulitic residue of the island arc. The results indicate that the crystallization cycle of the island arc began at ca. 100.9 ± 0.85 Ma and ended at ca. 78.4 ± 6.4 Ma. The arc plutons were emplaced in volcanic rocks with oceanic plateau affinity and vulcanites of the same arc. The spatial distribution analysis of the crystallization ages of the plutons, together with an analysis of the relative depth of melt generation shows that the ages become younger towards the east of the arc and that the depth of melting of these eastern plutons was greater, suggesting that subduction occurred in a west-to-east direction.

Keywords : Cretaceous; Volcanic Arc; Barroso-Sabanalarga Arc; Northern Andes..

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