El Cerro Campanario, un destacado hito natural en la divisoria continental cerca de Paso Pehuenche, es el remanente dejado por erosion glacial de un estratovolcano mafico mas joven de lo supuesto anteriormente. Tal como lo indican los analisis 40Ar/39Ar y K-Ar de sus bastante uniformes lavas de andesitas basalticas, ricas en olivina y plagioclasa, su edificio de 10-15 km3 crecio rapidamente hacia fines del Pleistoceno medio (150-160 ka).Cerro Campanario, a towering landmark on the continental divide near Paso Pehuenche, is a glacially eroded remnant of a mafic stratovolcano that is much younger than previously supposed. Consisting of fairly uniform basaltic andesite, rich in olivine and plagioclase, the 10-15 km3 edifice grew rapidly near the end of the middle Pleistocene, about 150-160 ka, as indicated by 40Ar/39Ar and unspiked K-Ar analyses of its lavas.