Activity at Chullkani commenced in the upper Miocene with the cryptodome Ch'ankha Muqu. This lava dome is formed by porphyritic andesite and has dimensions of at an altitude of . Later, southeast of Chullkani formed the rhyolitic Yapu Qullu lava dome. Crystalline flows named Thuwas Qalani (Tobas Khalani) are up to thick and contain lithic fragments and pumice. Chullkani proper formed 6.13± 0.12 Ma from andesites. Another group of five peaks stretching northeast are lava domes and named Jitiri, Picha Qullu (Picha Kkollu), Llallawi (Llalahui) (or Llallani), Jach'a K'uchu and Wila Lat'arata. A dacite lava dome named Liyun Ikiña was erupted 6.2±0.4 Ma.