Nevado Tres Cruces 1.84

Nevado Tres Cruces is a massif of volcanic origin in the Andes Mountains on the border of Argentina and Chile. It has two main summits, Tres Cruces Sur at and Tres Cruces Centro at 6629m and a third more minor summit, Tres Cruces Norte 6206m. Tres Cruces Sur is the sixth highest mountain in the Andes. The area was first surveyed in 1883 by Francisco San Román and the Nevado Tres Cruces National Park was established in 1994.The volcano has an extended history of activity, going back at least 1.5 million years. A number of lava domes surround the complex and a number of craters lie on its summits. The main volcano is of rhyodacitic composition and has generated two major ignimbritic eruptions, one 1.5 million years ago and a second 67,000 years ago. The last eruption was 28,000 years ago, but the volcano may become active in the future.Climate and glaciationThe area has a desert climate, with nighttime temperatures below freezing and precipitation less than 29±14 mm in the local summer that quickly sublimates away, resulting in a lack of surface runoff and a barren landscape. The mean annual temperature is -2±4 degrees Celsius. The area is persistently very windy. The snowline altitude in the area is 5800m, higher than the Pleistocene altitude of 5500m. Small relic glaciers with surfaces of less than exist above 5500m with moraines visible above 4400m. In 2000 a total ice surface of 1.1km2 was reported on Tres Cruces.