[3] Los Frailes belongs to the Central Andean ignimbrites,[6] which cover parts of southern Peru, southwestern Bolivia, northwestern Argentina and northeastern Chile[7] and which contains the Altiplano–Puna volcanic complex.

They consist of mostly welded tuffs with column-like joint structures;[13] a total volume of 2,000 cubic kilometres (480 cu mi) has been estimated for the plateau, which is a large size.

[15] Cerro Villacollo in the western sector of the plateau[5] is am eroded composite volcano[14] with a 200–600 metres (660–1,970 ft) deep and 3 kilometres (1.9 mi) wide collapse structure, and is accompanied by dacitic lava flows,[4] whereas Cerro Pascual Canaviri and Nuevo Mundo are complexes of lava domes, the latter of which also contains ash deposits that have been in part transported away by wind.

[6] The basement beneath Los Frailes is of Paleozoic–Mesozoic age and covered by Miocene andesitic-dacitic volcanics; some of these have been dated to 11.6 and 20 million years ago.

The main ignimbrite is of rhyodacitic composition[22] and contains phenocrysts consisting of apatite containing monazite and zircon, biotite, ilmenite, orthoclase, plagioclase and quartz.

[23] Silver-tin deposits occur in the volcanic field, including the Cerro Rico stock that was a principal source of silver to the Spanish Empire.

[30] Nuevo Mundo is the youngest eruptive system of the Los Frailes plateau;[15] based on the position of its lavas with respect to moraines it must have been active within the last 11,000 years in the Holocene,[31] perhaps even in prehistoric time.