Tronador ( es, Cerro Tronador) is an extinct stratovolcano in the southern

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

, located along the border between

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

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 ...

, near the Argentine city of

Bariloche San Carlos de Bariloche, usually known as Bariloche (), is a city in the province of Río Negro, Argentina, situated in the foothills of the Andes on the southern shores of Nahuel Huapi Lake. It is located within the Nahuel Huapi National Park ...

. The mountain was named ''Tronador'' (

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

for "Thunderer") by locals in reference to the sound of falling seracs. With an altitude of , Tronador stands more than 1,000 m above nearby mountains in the Andean massif, making it a popular mountaineering destination. Located inside two national parks,

Nahuel Huapi Nahuel Huapi National Park () is the oldest national park in Argentina, established in 1934. It surrounds Nahuel Huapi Lake in the foothills of the Patagonian Andes. The largest of the national parks in the region, it has an area of , or nearl ...

in Argentina and

Vicente Pérez Rosales Vicente Pérez Rosales (; 5 April 1807 – 6 September 1886) was a politician, traveller, merchant, miner and Chilean diplomat that organised the colonisation by Germans and Chileans of the Llanquihue area. Vicente Pérez Rosales National Park ...

in Chile, Tronador hosts a total of eight

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

s, which are currently retreating due to warming of the upper

troposphere The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...

.Bown, Francisca. 2004. Cambios climáticos en la Región de Los Lagos y respuestas recientes del Glaciar Casa Pangue (41º08’S). Tesis para optar al grado de Magíster en Geografía.

Universidad de Chile The University of Chile ( es, Universidad de Chile) is a public research university in Santiago, Chile. It was founded on November 19, 1842, and inaugurated on September 17, 1843.

Geography and geology

Cerro Tronador is in the Wet Andes, a zone of high precipitation of both snow and rain. The humid temperate climate of the southern Andes has allowed several glaciers to develop due to high

accumulation Accumulation may refer to: Finance * Accumulation function, a mathematical function defined in terms of the ratio future value to present value * Capital accumulation, the gathering of objects of value Science and engineering * Accumulate (hi ...

rates. Most of the precipitation is produced by western

frontal system A weather front is a boundary separating air masses for which several characteristics differ, such as air density, wind, temperature, and humidity. Disturbed and unstable weather due to these differences often arises along the boundary. For ins ...

s from the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

. Located in the middle of the Andean massif at a latitude of 41° S, Tronador is part of an alpine landscape of

fjord In physical geography, a fjord or fiord () is a long, narrow inlet with steep sides or cliffs, created by a glacier. Fjords exist on the coasts of Alaska, Antarctica, British Columbia, Chile, Denmark, Förden and East Jutland Fjorde, Germany, ...

s, glacial lakes, and

U-shaped valley U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight s ...

s. The forming of the landscape took place during the

Quaternary glaciation The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma (million years ago) and is ongoing. Although geologists describ ...

s, periods during which the whole area was covered by the

Patagonian Ice Sheet upright=1.4, Map showing the extent of the Patagonian Ice Sheet in the Strait of Magellan area during the last glacial period. Selected modern settlements are shown with yellow dots. Sea level was much lower than shown here. The Patagonian Ice S ...

. The volcano grew during the

glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

s and interglacials of the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological 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 finally confirmed in ...

but became practically extinct in the late Middle Pleistocene, approximately 300 ka ago, due to a shift in the active front of the Southern Volcanic Zone to which it belongs.Mauricio Mella, Jorge Muñoz, Mario Vergara,Erik Klohn, Lang Farmer, Charles R. Ster
Petrogenesis of the Pleistocene Tronador Volcanic Group, Andean Southern Volcanic Zone
Revista Geológica de Chile Since then, glaciations and other erosive processes shaped the mountain freely without new output of

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

tephra Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they re ...

. As in the case of nearby Lanín volcano, Tronador is composed mostly of

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

s, and has seen a decline in activity as the Osorno and

Calbuco Calbuco is a city and commune in southern Chile administered by the Municipality of Calbuco. Administratively Calbuco belongs to the Llanquihue Province of Los Lagos Region. The origin of the city was the Spanish Fort Calbuco founded in 1603, an ...

volcanoes grow further west.

Glaciers

Tronador is notable for the many glaciers covering parts of its flanks. Up to eight glaciers have been inventoried: Alerce, Ventisquero Negro, Casa Pangue, Castaño Overa, Río Blanco, Frías, Peulla, and Manso. Over the last decades the glaciers on Tronador, like the majority of southern Andean glaciers, have been retreating. The Casa Pangue glacier on the northwestern side of Tronador experienced a thinning between 1961 and 1998, with an increased rate of retreat between 1981 and 1998 at 52 m a⁻¹. The retreat and thinning is attributed to a decrease in precipitation and a warming of the upper

over the last several decades. Alerce Glacier, on the Argentinian side, can be visited from Refugio Otto Meiling, a mountain hut that is sandwiched between it and Castaño Overa Glacier. Castaño Overa, also on the Argentinian side, is smaller and relatively accessible by hike from Pampa Linda. Guided trekking tours allow visitors to cross Castaño Overa or walk to Tronador's peak. Ventisquero Negro ("black snowdrift" in Spanish) is a rather unusual glacier at the base of Tronador in

Nahuel Huapi National Park Nahuel Huapi National Park () is the oldest national park in Argentina, established in 1934. It surrounds Nahuel Huapi Lake in the foothills of the Patagonian Andes. The largest of the national parks in the region, it has an area of , or nearly ...

. Its unusual dark brown colour comes from dirt and sediment picked up in the glacier's accumulation zone, which is fed by the Río Manso Glacier several hundred metres higher up the mountain. Brown icebergs calve from the glacier and then float in a small lake until eventually melting.

Peaks

According to the Aoneker map, these are the named peaks on Tronador: Anon or Internacional (3484m), Argentino (3187), Chileno (3262), and Torre Ilse (2585). Named ridges include Filo Sur (3054), Filo Blanco (3146), Filo La Vieja (2715), and Filo Lamotte (2340).

Mountaineering and tourism

Tronador was first climbed by Hermann Claussen solo on 29 January 1934, after several attempts. A

mountain hut A mountain hut is a building located high in the mountains, generally accessible only by foot, intended to provide food and shelter to mountaineers, climbers and hikers. Mountain huts are usually operated by an Alpine Club or some organization ...

, Refugio Otto Meiling, is the destination of popular day hikes on the mountain, and is named after a German mountaineer who made dozens of ascents and spent years guiding people around it. The hut is located about 1200m vertically above Pampa Linda, at the mountain's base. Most summers the Internacional or Anon peaks (the highest of Tronador's three peaks) is climbable. However, an unusually hot summer increased

rockfall A rockfall or rock-fallWhittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984. . is a quantity/sheets of rock that has fallen freely from a cliff face. The term is also used for collapse of rock from roof or walls of mi ...

to dangerous levels during January and February 2008. The Argentine side risks becoming no longer accessible due to increasingly warm weather in the region destabilising the glaciers.

Gallery

File:Tronador from Pampa Linda Stevage.jpg, Seen from Pampa Linda. File:Cerro Tronador - cordillera de los Andes.JPG File:Glacier Alerce Stevage.jpg, Alerce Glacier, one of Tronador's 7 glaciers.

References