Nevado Ojos del Salado is a dormant complex volcano in the Andes on the Argentina–Chile border. It is the highest volcano on Earth and the highest peak in Chile. The upper reaches of Ojos del Salado consist of several overlapping lava domes, lava flows and volcanic craters, with an only sparse ice cover.
The Ojos del Salado lake in the Andes is the world’s highest lake. It is situated on the eastern face of Ojos del Salado, the world’s highest active volcano.
Ojos del Salado hosts the highest lake in the world in the form of the crater lake in the summit crater. Fed by permafrost and snowfields, it lies at 6,480 meters - 6,500 meters elevation. It is surrounded by fumaroles and covers an area of 6,000 square meters. Waters in a creek flowing into this lake reach temperatures of 40.8 °C.
There are two lakes at 5,900 meters elevation on the northeastern slope, 4 kilometers away from the higher lake. Each has an area of 2,500 square meters and an estimated depth of 1 meter. Ephemeral lakes occur at 5,900–6,000 meters elevation, when melt water from permafrost accumulates in closed depressions. Such ponds may form in depressions at 6,380 meters elevation. Some of the lakes may be permanently frozen. Lakes might disappear with climate change owing to the breakdown of permafrost.
According to wikipedia