It consists of a volcanic cone with a summit crater, surrounded at its foot by lava flows erupted from flank vents.

Peinado lies in Argentina's Catamarca Province,[4] close to the border with Chile and about 30 kilometres (19 mi) from the Paso San Francisco.

[5] They consist of lava flows, maars, scoria cones and tuff rings, with volumes reaching 0.8 cubic kilometres (0.19 cu mi), and were emplaced between 600,000 and 150,000 years ago.

[23] At the northern end of the basin, coastal terraces reach thicknesses of 30–40 centimetres (12–16 in) and lengths of several 100 metres (330 ft),[22] they extend to Laguna Turquesa.

[24] Lake sediments consist of an alternation of organic muds, calcite and travertine,[18] with limestones occurring in coastal areas and muddy deposits in deeper waters.

[26] They may be correlative with regional changes in humidity, but difficulties in dating lake deposits prevent the determination of a definitive causal relationship.

[27] The lakes of the Altiplano have drawn attention in the 21st century owing to the frequently extreme climatic and hydrological conditions they experience.

[32] Peinado is part of the Central Volcanic Zone of the Andes,[11] which in northern Argentina extends across the Cordillera Occidental and the Altiplano.

[15] Numerous volcanoes occur in the region, including Laguna Amarga, Sierra Nevada de Lagunas Bravas, Laguna Escondida, Cerro El Condor, Wheelwright caldera, Falso Azufre, Nevado Tres Cruces, Ojos del Salado, Incahuasi, Cerro Torta, Cerro Blanco, Cueros de Purulla and numerous other calderas with accompanying ignimbrites, and monogenetic volcanoes.

[11] Apart from volcanoes, tectonically-generated basins and ridges form a steep relief in the region;[17] the Laguna Peinado occupies one of several north-south trending tectonic depressions in the area.

[11] They define a potassium-rich calc-alkaline suite[33] and contain phenocrysts of clinopyroxene, iron-titanium oxides, olivine, orthopyroxene and plagioclase.

[35] Radiometric dating has yielded ages ranging between 80,000 and 40,000 years ago for the central cone and between 60,000 and 30,000 for the flank vents.

[37] Eventually, the cone reached a size at which further eruptions from the summit were impeded, causing volcanism to shift to the flank vents, which then built up the bulk of Peinado.

The volcano lies on an eastward younging trend of calderas including Laguna Amarga, and there is evidence of magma storage in the crust.

[51] A prehistoric copper and aragonite mine with well-preserved buildings lies at Tambería El Peinado, close to the volcano.