The age and constitution of Cerro Campanario, a mafic stratovolcano in the Andes of central Chile

 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.