Purico Complex

The Purico volcanic complex consists of two ignimbrite sheets, separated by a short erosional interval, that were erupted about 1.3 million years ago, along with several stratovolcanoes and lava domes that define a postulated 10 x 20 km ring fracture. Cerro Toco volcano overlies the vent area of the Cajón Ignimbrite. A sulfur mine on its SE flank was mined until the early 1990s. The youngest lava domes, Cerro Chascón de Purico and Cerro Aspero are of Holocene age (de Silva and Francis, 1991). Both domes differ morphologically from many other flat-topped silicic Andean volcanic domes and have conical profiles. The Cerro Chascón de Purico dacitic dome was formed by a series of viscous lava flows and has a well-preserved summit crater and lava flows that show no evidence of glacial modification. The Cerro Aspero appears to be a single Pelean-type dome. The dacitic-to-andesitic Macon stratovolcano of Holocene age lies at the southern end of the complex, and the Alitar maar at the SE end displays constant solfataric activity.