Acotango is the central and highest of a group of

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...

es straddling the border of

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

and

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. It is high. The group is known as Kimsa Chata and consists of three mountains: Acotango,

Umurata Umurata is a mountain in the Andes, about 5,717 m (18,757 ft) high, situated in the Cordillera Occidental on the border of Bolivia and Chile. It is located in the Arica and Parinacota Region of Chile and in the Oruro Department of Bo ...

() north of it and Capurata () south of it. The group lies along a north–south alignment. The Acotango volcano is heavily eroded, but a lava flow on its northern flank is morphologically young, suggesting Acotango was active in the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

. Later research has suggested that lava flow may be of

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

age. Argon-argon dating has yielded ages of 192,000±8,000 and 241,000±27,000 years on

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

s from Acotango. Glacial activity has exposed parts of the inner volcano, which is hydrothermally altered. Glacial

moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

s lie at an altitude of but a present ice cap is only found past of altitude. The volcano is a popular hiking route in the

Sajama National Park Sajama National Park is a national park located in the Oruro Department, Bolivia. It borders Lauca National Park in Chile. The park is home to the indigenous Aymara people, whose influential ancient culture can be seen in various aspects throu ...

and

Lauca National Park Lauca National Park is located in Chile's far north, in the Andean range. It encompasses an area of 1,379 km2 of altiplano and mountains, the latter consisting mainly of enormous volcanoes. Las Vicuñas National Reserve is its neighbour to ...

. It is on the border of two provinces: Chilean province of

Parinacota Parinacota (in hispanicized spelling), Parina Quta or Parinaquta (Aymara, ''parina'' flamingo, ''quta'' lake, "flamingo lake", other hispanicized spellings ''Parinaccota, Parinajota'') may refer to: Lakes * Parinaquta (Carabaya), in Peru, Puno R ...

and Bolivian province of Sajama. Its slopes are within the administrative boundaries of two cities: Chilean commune of

Putre Putre is a Chilean town and commune, capital of the Parinacota Province in the Arica-Parinacota Region. It is located east of Arica, at an altitude of . The town is backdropped by Taapaca volcanic complex. Putre is on the edge of the Lauca Na ...

and Bolivian commune of Turco. To climb the summit from the Chilean side is dangerous due to land mines, however it is relatively safe to climb the summit from the Bolivian side. The southern ascent starts over a glacier and passes an abandoned copper mine.

First Ascent and human presence

Acotango's first modern ascent was by Sergio Kunstmann, Pedro Rosende and Claudio Meier (Chile) October 14, 1965. It is believed that Pedro Rosende, a Chilean explorer, found the remains of firewood at the summit of Acotango. Because of this, it is thought that the mountain might have been one of the high Incan Andean sanctuaries. However, more exploration is needed to verify this information.Chiles 6000 nd Volcan Acotango South Face http://www.los6000dechile.cl/pdf/bch_cumbres_03_acotango.pdf

Notes

References

Volcanoes of Arica y Parinacota Region Stratovolcanoes of Chile Subduction volcanoes Pleistocene stratovolcanoes Volcanoes of Oruro Department Mountains of Chile Bolivia–Chile border International mountains of South America Six-thousanders of the Andes {{AricaParinacota-geo-stub

First Ascent and human presence

See also

Notes

References