Arizaro volcanic field

The volcanic field lies above the western shores of the Salar de Arizaro. It consists of numerous Pleistocene basaltic andesite lava flows, as well as cinder cones with Holocene basaltic lava flows. Most centres are roughly aligned in northeast–southwest direction;^[1] they are named Estación Caipe, Panqueque, Chuculaqui y Samenta, Medialuna, Puesto Flores, Vega de Samenta and Pie de Samenta. Most of them lie on the slopes of the terrain west of Salar de Arizaro, except Medialuna which is in the salar and Panqueque which is on its edge.^[2] Panqueque is 60 metres (200 ft) high and covers an area of 3 square kilometres (1.2 sq mi); it consists of a body of lava flows emitted from several centres—the westernmost centre being the most important—overlying pyroclastic deposits that crop out at the edge of the lava flows.^[3] The lava flows have well-developed flow shapes like ogives.^[4] When it erupted, Panqueque tore up rocks from the underlying substrate, like sediments, which are now mixed in the volcanic rocks.^[5] Medialuna is a 15 metres (49 ft) high, 390 metres (1,280 ft) long crescent-shaped volcanic structure that opens to the east.^[6] Both centres formed in phreatomagmatic eruptions, which in the case of Panqueque transitioned over time into effusive activity.^[7]

The volcanic field lies in the Puna, a high plateau generated by the subduction of the Nazca Plate beneath the South America Plate.^[8] The terrain consists mainly of Miocene volcaniclastic rocks with a single outcrop of Ordovician granodiorite. Parts of the area are covered by Quaternary alluvium and conglomerates. The basement rocks are influenced by normal faulting^[1] and the region is criss-crossed by ridges.^[9]