The Nevados de Sollipulli mountain chain west of the Sollipulli caldera are a chain of volcanoes which is heavily eroded. They are formed by breccia and lava flows; glacial action has left cirques. Closer to the caldera they are better preserved, with individual flows issuing from fissure vents. This chain is one of several east-northeast striking volcano alignments in the Southern Volcanic Zone, the regional tectonics favour magma ascent along such alignments.