Abstract

RODRIGUEZ-GARCIA, Gabriel et al. Redefinition, correlation and geotectonic implications of the batholith of Ibagué, Colombia. Bol. geol. [online]. 2022, vol.44, n.3, pp.65-93.  Epub Nov 21, 2022. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v44n3-2022003.

New fieldwork, pétrographie, geochemical, and zircon U-Pb geochronologic data allow us to identify new units and redefine the limits of the Ibagué batholith. The Ibagué batholith, located to the north of the Ibagué Fault, was divided into two geological units: the Anzoátegui Metatonalite (~194.7 km2) and Ibagué Tonalité (~278 km2). To the south of the Ibagué fault, the name Ibagué batholith is maintained, but its original extension changes to ~3200 km2 due to theoccurrence of the Carboniferous Belalcázar and Los Guayabos gabbros, the Permian Ortega and La Plata granites, and the early Jurassic Páez quartz-monzodiorite. The Anzoátegui Metatonalite and Ibagué Tonalite are composed of calc-alkaline and metaluminous metatonalites, tonalites, and granodiorites, yielding U-Pb crystallization ages between 158.2+1.2/-0.4 and 150.17±0.86 Ma, and between 145.71+0.72/-1.42 Ma and 138.48±0.95 Ma, respectively. The Ibagué batholith is constituted by calc-alkaline to high K calc-alkaline, metaluminous and peraluminous, tonalites, granodiorites, and monzogranites, yielding crystallization ages between 171.5±1.3 and 137.9±1.0 Ma. The Ibagué batholith, the Anzoátegui Metatonalite, and the Ibagué Tonalite are calcic granitoids generated in an arc environment, presenting Nb, Ti, and P negative anomalies. The geotectonic position, petrographic and geochemical composition, and crystallization ages allowed us to correlate the Ibagué batholith, the Anzoátegui Metatonalite, and the Ibagué Tonalite with the Segovia and Los Alisales batholiths, the Siapana granodiorite, the Payandé stock, and volcanic units such as the La Malena volcanic rocks, the Segovia and Chaparral vulcanites. This correlation also drives the separation of the Ibagué batolith from other units like the Carboniferous, Permian, and Early to Middle Jurassic plutons cropping out further east.

Keywords : Jurassic magmatism; Lithogeochemistry; U-Pb zircon dating.

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