Vilama (caldera)

Vilama caldera
Vilama caldera
Highest point
Elevation	5,340 m (17,520 ft)
Coordinates	22°24′S 66°57′W / 22.400°S 66.950°W / -22.400; -66.950[1]

Vilama is a Miocene caldera in Bolivia and Argentina. Straddling the border between the two countries, it is part of the Central Volcanic Zone, one of the four volcanic belts in the Andes. Vilama is remote and forms part of the Altiplano-Puna volcanic complex, a province of large calderas and associated ignimbrites that were active since about 8 million years ago, sometimes in the form of supervolcanoes.

The Vilama caldera was originally estimated to have a size of 40 by 65 kilometres (25 mi × 40 mi) but the size was later revised to be between 15–18 kilometres (9.3–11.2 mi) and 35–40 kilometres (22–25 mi) and is almost entirely buried beneath younger volcanoes that have grown along the margin of the caldera; volcanic activity on these volcanoes continued into the Pleistocene. Several lakes also developed on the floor of the caldera, which contains a resurgent dome.

Vilama is the source of the enormous Vilama ignimbrite, which was emplaced during an eruption with a volcanic explosivity index of 8 about 8.4–8.5 million years ago. A large amount of the Vilama ignimbrite is inside the caldera depression, while the part outside of the caldera covers a surface area exceeding 4,000 square kilometres (1,500 sq mi). The total volume of the ignimbrite is about 1,200–1,800 cubic kilometres (290–430 cu mi), possibly as much as 2,100 cubic kilometres (500 cu mi). Another large ignimbrite, the Sifon ignimbrite, may also have been erupted by Vilama, while the Granada ignimbrite was later attributed to a separate volcano.