Chiqllarasu lies north-east of the mountain Saywa Q'asa, between the villages Patawasi (Patahuasi) in the northwest and Kichkawasi (Quichcahuasi) in the southeast.

(Guillou-Frottier, Burov & Milési 2000, p. 352) The caldera was formed on a central volcano which erupted andesite and dacite.

The Atunsulla tuff was erupted from Chiqllarasu around 2.4 million years ago (Guillou-Frottier, Burov & Milési 2000, p. 342).

A long break in volcanic activity, during which the edifice was deeply eroded, may have occurred before this eruption(Noble & McKee 1982, p. 1895).

Hydrothermal activity occurred both before and after the eruption of the Atunsulla tuff, and the mineralization occurred 1.9 million years ago(Guillou-Frottier, Burov & Milési 2000, p. 342), This volcano is among the youngest in a Central Peru volcanic chain (Noble & McKee 1982, p. 1893); hot water indicate that the geothermal system may be still active (Noble & McKee 1982, p. 1897).