The Pali-Aike volcanic field is a volcanic field along the Argentina–Chile border. It is part of a family of back-arc volcanoes in Patagonia, which formed from processes involving the collision of the Chile Ridge with the Peru–Chile Trench. It lies farther east than the Austral Volcanic Zone, the volcanic arc that makes up the Andean Volcanic Belt at this latitude. Pali-Aike formed over sedimentary rock of Magallanes Basin, a Jurassic-age basin starting from the late Miocene as a consequence of regional tectonic events. The volcanic field consists of an older plateau basalt formation and younger volcanic centres in the form of pyroclastic cones, scoria cones, maars and associated lava flows. There are approximately 467 vents in an area of 4,500 square kilometres (1,700 square miles). The vents often form local alignments along lineaments or faults, and there are a number of maars and other lakes, both volcanic and non-volcanic. The volcanic field is noteworthy for the presence of large amounts of xenoliths in its rocks and because the maar Potrok Aike is located here, where palaeoclimate data have been obtained. The field was active starting from 3.78 million years ago. The latest eruptions occurred during the Holocene, as indicated by the burial of archaeological artifacts; the Laguna Azul maar formed during the Holocene. Humans have lived in the region for thousands of years, and a number of archaeological sites such as the Fell Cave are located in the field. Presently, parts of the volcanic field are protected areas in Chile and Argentina, and the city of Rio Gallegos in Argentina is within 23 kilometres (14 mi) of the volcanic field.
Name The name Pali-Aike comes from the Tehuelche language, where pale means "hunger" and aike means "location". Originally it was the name of a farm (estancia) and was later applied to the volcanic field.
Human geography The Pali-Aike volcanic field spans the border between Argentina and Chile, northwest of the Magellanes Strait. Most of the field lies in Argentina within the southernmost part of Santa Cruz Province, while the Chilean part is in the commune of San Gregorio, Chile. The cities of Rio Gallegos (Argentina) and Punta Arenas (Chile) lie northeast and southwest of Pali-Aike respectively. Unusually for Argentine volcanoes, Pali-Aike volcanoes are close to urban areas since the closest vent is only 23 kilometres (14 mi) or 30 kilometres (19 mi) away from Rio Gallegos; the vents are easily observed from the city. The Monte Aymond border pass lies next to the volcanic field and Argentine National Route 3 passes through the Pali-Aike volcanic field. The border crossing Paso Integración Austral lies next to the volcanic field. On the Chilean side there are hiking trails.
Geography and structure
Local The Pali-Aike volcanic field covers a surface area of 4,500 square kilometres (1,700 square miles), and extends over 150 kilometres (93 mi) from northwest to southeast. It is formed by a plateau of lava flows that is up to 120 metres (390 ft) thick (in its northwestern reach), with an average relief of 20–100 metres (66–328 ft). This plateau is formed by tables containing depressions and lakes, and whose margins are steep-dipping slopes that accumulate blocks at their feet. It includes remnants of individual volcanic centres, and some volcanic necks situated in the west–central part of the field may be the formerly underground components of now-eroded volcanic edifices. Among these volcanic necks are the Cuadrado, Domeyko, Gay and Philippi hills, which conspicuously stick out of the surrounding plains. The volcanic rocks were emplaced atop Cenozoic- to Tertiary-age sediments, which were smoothened by glacial action. The sediments are often unstable and prone to mass wasting and landslides.
There are 467 volcanic vents in the field. Monogenetic volcanoes are emplaced on the lava plateau at elevations of 110–180 metres (360–590 ft) above sea level and include maars, tuff rings and scoria cones. These various centres rise between 20–160 metres (66–525 ft) above the surrounding terrain. Nested craters, breached craters and fissure vents are common among the various vents, as are lava flows, but there has been little research on the scoria cones. Lava flows embedded in valleys reach lengths of 8 kilometres (5 mi). Pyroclastic cones in Pali-Aike include Aymond, Colorado, Dinero, Fell and Negro. The vent Cerro del Diablo, a pyroclastic cone, is the youngest volcano in the field and has emitted both ʻaʻā and pahoehoe lava, which have a fresh appearance and no soil cover. The vents were origins of lava flows, which sometimes breached the vents. Some flows are older and covered with soil while younger ones are not. Such young lava flows also have surface features including lava tunnels, hornitos, tumuli and a wrinkled surface. Some of these are heavily eroded while the southeastern part of the field features fresh-looking centres, where they form the "Basaltos del Diablo". The individual volcanoes are subdivided into three groups, which are referred to as "U1" (the plateau lavas), "U2" (the older centres) and "U3" (for the more recent vents).
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