One andesitic lava flow on the northwestern slope of Incahuasi has yielded two ages, one of 1.15 ± 0.5 million years ago and another of 710,000 ± 80,000 years ago. Based on their preservations, the lava flows appear to be of roughly comparable ages. Additional ages were obtained on the main edifice, 1.57 ± 0.1 million years ago, 1.14 ± 0.37 million years ago, and 1.00 ± 0.13 million years ago.