Aucanquilcha (pronounced: OW-kahn-KEEL-chuh) is a massive stratovolcano located in Antofagasta Region of northern Chile, just west of the border with Bolivia. It comprises a number of overlapping cones along a 10 km (6 mi) long ridge that forms the summit. There is weak, episodic fumarolic activity and voluminous sulfur deposits in the summit region. During the Pleistocene ice ages, an extensive ice cap with an area over 45 km² (17 mi²) mantled the upper slopes, extending down as low as 4,600 m (15,000 ft) and leaving large moraines.