Parinacota, a composite volcano, is located on the Chilean/Bolivian frontier and is one of two volcanoes that makes up the Nevados Payachata range. The other older volcano, Pomerape, is located to the northeast of Parinacota and makes up the northern part of this volcanic range.
Parinacota is made-up of an older dome which seams to have collapsed toward the southwest obstructing drainage with in the local area resulting in the formation of Lake Chungara. Seepage of water through this deposited avalanche debris feeds numerous smaller lakes within this terrain.
A pronounced crater of about 300m in diameter is located at the summit of the young cone that formed after the major cone collapse which is estimated to have occurred about 13,500 years ago. Pristine lava flows cover Parinacota's western flanks and hold testement to this volcanoe's continued activity that has continued into recent times.
Source of Information
De Silva, Shanaka & Peter W. Francis, Volcanoes of the Central Andes, Springer-Verlag, New York 1991, p.44-45.