In the Upper Magdalena Valley, subvolcanic porphyritic andesite and latite rock bodies intrude volcanic lavas and tuffs of the Lower Jurassic Saldana Formation. These rock bodies are characterized by plagioclase phenocrysts up to 2 cm in diameter, together with pyroxene, olivine and sanidine crystals, floating in a hyalocrystalline matrix. They correspond to hypabyssal, alkaline plutons of the metaluminous series, with high alkali content, chemically classified as andesites and interpreted to be generated by subduction in an arc environment, in accordance with their negative Nb and Ti anomalies and LREE/HREE ratios in multielement diagrams. An Ar-Ar plateau age of 159.35 ± 3.55 Ma was obtained in plagioclase, which suggests, along with the chemical characteristics and stratigraphic relationships, that it corresponds to a magmatic event younger than the lavas of the Saldana Formation (186.8 ± 2.0–188.9 ± 1.6 Ma), the Pitalito Vulcanites (168 ± 2.5–172.4 ± 1.7 Ma) and the Jurassic plutons that crop out in the Upper Magdalena Valley (169.4 ± 3–195.8 ± 1.5 Ma).