La Negrillar

The basaltic andesite La Negrillar cone and lava flow complex (also known as Aguas Perdidas) covers a roughly 50 km2 area along the SW margin of the Atacama basin about 35 km WNW of Socompa volcano between the small Sierra San Juan and Sierra Almeida ranges. It was interpreted to be Holocene by de Silva and Francis (1991), though Gardeweg (1993, pers. comm.) did not consider it to be of Holocene age. Additionally, de Silva (2007, pers. comm.) noted that it was not as youthful looking as the El Negrillar complex to the N, although it did show leveed lava flows and pristine craters.