Acotango is the central and highest of a group of

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

es straddling the border of

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

and

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. It is high. The group is known as Kimsa Chata and consists of three mountains: Acotango, Umurata () 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 geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

. Later research has suggested that lava flow may be of

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 (geology), 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 gla ...

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 and Lauca National Park. 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 ...

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 Lauc ...

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