The Noreán Formation (Spanish: Formación Noreán, J1-2n, J1n) is a geological formation of the Eastern Ranges of the Colombian Andes, the Serranía de San Lucas and as basement underlying the southernmost and northern Middle Magdalena Valleys. The formation consists of volcanic and pyroclastic lavas that range from andesites to rhyolites. Vitric, lithic and crystal tuffs and andesitic dikes and hypabyssal bodies are also present in the formation.