Perito Moreno Glacier
| Perito Moreno Glacier | ||
|---|---|---|
 Glacier end of the Perito Moreno Glacier (2004, two weeks before a breakthrough occurred from Brazo Rico (below), the cordoned off southern part of Lake Argentino ) |
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| location | Patagonia , Argentina | |
| Mountains | To the | |
| Type | Outlet glacier | |
| length | 30 km | |
| surface | 254 km² | |
| Exposure | east | |
| Altitude range | 2950 m - 185 m | |
| Coordinates | 50 ° 29 ′ S , 73 ° 3 ′ W | |
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| drainage | Lake Argentino | |
| particularities | periodically blocks and dams the southern arm of the lake. | |
The Perito Moreno Glacier is one of the largest outlet glaciers of the Campo de Hielo Sur , the largest glacier area in the South American Andes . It is located in Patagonia in southwest Argentina in the province of Santa Cruz . Glaciers is known primarily in that its in Lago Argentino ending glacier the southern arm of the lake shuts off and dams, which then emptied periodically. The glacier was named after Perito Moreno , an Argentine geographer who dedicated himself in particular to Patagonia. Today the glacier is one of the biggest tourist attractions in Argentina, it is the most visited place of the Los Glaciares National Park, which is classified as a UNESCO World Heritage Site . In contrast to most of the region's glaciers, the Perito Moreno Glacier is not retreating, and the mass balance shows no clear trend.
morphology
The upper limit of the glacier is drawn on the continental watershed , the ice divide has an average height of 2200 m , the highest point is at 2950 m at Cerro Pietrobelli . From there the glacier stretches for about 30 km eastwards to Lake Argentino . Based on satellite images from 1999, a glacier area of 254 square kilometers was determined.
The glacier reaches Lake Argentino at its southern foothills and separates two of the tributaries , namely Brazo Rico in the south from the Canal de los Témpanos further north . At times the glacier bridges the entire side arm of the lake and reaches the opposite bank, in the far west of the Magellan Peninsula. The calving front in the Canal de los Témpanos is 2.3 km long, that in Brazo Rico 2.1 km and the length of the front on the west side of the Magellan Peninsula is 0.5 km. The height of the calving front is 55 to 77 meters above the waterline. The deepest point near the front in Brazo Rico is 110 m, in the Canal de los Témpanos it is 164 m. At no point does the glacier form a floating tongue. The calving speed is greatest in the middle of the front in the Canal de los Témpanos, where a value of 795 meters per year was determined.
Periodic damming and eruption of Brazo Rico
The first usable photo of the glacier from 1899 shows that the end of the glacier was one kilometer above the current glacier front. In the following years he advanced until the first documented damming of the Brazo Rico occurred in 1917. In the meantime there have been more than 20 such impoundments and evacuations, and the process is typically repeated every two to four years. During the damming in 1965, a water level rise of 28.4 m in Brazo Rico is reported, but this seems exaggerated, since the vegetation in the area of the southern branch suggests a maximum rise of 23.5 meters. In addition, if the water rose more than 25 meters above the lower-lying areas in the north-eastern part of the Brazo Rico, it would flow away and thus prevent a further rise.
In the years between 1988 and 2003 the glacier reached the opposite bank several times, but there were no spectacular eruptions because the water could run off through channels in the ice. In 2003 the glacier front in the Canal de los Témpanos advanced by 100 to 120 meters, in the Brazo Rico it was 150 meters. In September 2003, the glacier finally blocked the flow of the Brazo Rico completely. The area of the southern parts of Lake Argentino - Brazo Rico and Brazo Sur - increased in the following period from about 150 km² to 172 km², the water level rose by 9.35 meters. On March 11th, the water began to break through, initially through cracks in the ice that enlarged. Two days later, a 60 meter high section of the ice front collapsed. Two years later, on March 13, 2006, the next such collapse of the ice dam occurred. The following eruption on July 9, 2008, Argentina's Independence Day, was the first known collapse in the winter months. This unusual timing could be related to global warming . The last outbreak so far occurred on March 12, 2018 at night.
Evolution of the glacier
Contrary to most of the region's glaciers, the Perito Moreno Glacier does not retreat. The mass balance of the last few decades shows no clear trend. The cause of this behavior could lie in the geometry of the glacier.
On the one hand, the end of the glacier in Lago Argentino plays a role. There the glacier meets the opposite bank of the lake on the Magellan Peninsula, and the water depth in front of the two glacier fronts to the right and left of it increases rapidly, which also prevents further advance of the glacier there, as the calving speed increases considerably with increasing water depth . The calving speed is unusually high for glaciers ending in fresh water, which suggests that this is one reason why the glacier's calving front has been so stable over the past few decades.
Another reason for the stability of the Perito Moreno Glacier could be that the glacier is relatively steep in the area of the equilibrium line ; increasing this by 100 meters means only a reduction in the size of the nutrient area by 4 percent.
history
The glacier was formerly called the Bismarck Glacier . In 1899, its discoverer, the German geologist Rudolph Hauthal , named it after the former Chancellor Otto von Bismarck , who died the previous year . It was only later named after Perito Moreno , in recognition of his merit as an explorer and anthropologist. In Germany, the name Bismarck Glacier was common until at least 1917.
Surroundings
The next larger town is El Calafate , around 80 km away , a popular starting point for tours through the national park and to the glacier.
Web links
Individual evidence
- ↑ a b c d e f g h i j Stuefer et al .: Glaciar Perito Moreno, Patagonia: climate sensitivities and glacier characteristics preceding the 2003/04 and 2005/06 damming events , 2007 ( online ; PDF; 685 kB)
- ↑ Spiegel Online : Argentine glacier bridge collapses on July 10, 2008
- ↑ Focus : Argentine glacier breaks away from July 5th, 2008
- ↑ El País: [1] , March 12, 2018