Cerro Negro de Mayasquer is an andesitic to dacitic stratovolcano on the Colombia-Ecuador border. It contains a caldera open to the west.
An historical eruption reported in 1936 is probably false and may have been from Reventador volcano.
Solfataras are found on the shore of a small crater lake.
The higher and glacier-covered summit of the extinct Chiles stratovolcano lies only 3 km to the SE. Chiles last erupted about 160,000 years ago, but still has hot springs and an active hydrothermal system at its eastern flank.
