Sierra Nevada, also known as Sierra Nevada de Lagunas Bravas, is a major ignimbrite-lava dome complex which lies in both Chile and Argentina in one of the most remote parts of the Central Andes. Activity in the complex started in Argentina and formed two stratovolcanoes. Later, 12 or more vents formed, some with craters up to wide. Lava flows up to long with flow ridges are also found. It covers a total area of 225 km². Radiometric dating has yielded ages of 1.7 ± 0.4 to 0.431 ± 0.012 million years ago. Together with Cerro el Condor and Peinado it forms the Culampaja line, a line of volcanoes that reaches Cerro Blanco. Strong seismic attenuation is observed beneath Sierra Nevada. Hydrothermally altered rocks in Sierra Nevada may be the source of sulfate and As in the Juncalito and Negro rivers.