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Volcan Lanin, Andes Mountains
Credit & Copyright: Dr. Bruce G.
Explanation: Towering some 12,388 feet (3,776 meters) into the clouds is this massive extinct volcano that straddles Argentina and Chile in the southern Andes Mountains of South America at nearly 40 degrees south latitude below the equator.
Volcan Lanin itself is actually a composite of four major geological periods of eruption and a number of layers, and is termed a compound stratocone.
But although the eruptions have subsided -- with the last eruption in the Holocene -- the ice is alive with daily meltwater. The glaciers are melting.
a few decades ago,
Studies have shown significant "retreat" of glaciers in the Andes Mountains in recent decades, apparently because of the warming of the atmosphere and lessening precipitation. Research on a nearby volcano, Volcán Mocho-Choshuenco, showed a 40% reduction in the area of glacier cover between 1976 and 2003.
glaciers melt, there is often a positive feedback effect leading to even
faster melting. The melting first uncovers darker-colored rock which
then absorbs sunlight and heat far more effectively than did the reflective
white of the ice and snow, so the land warms even
more quickly. In these photos of Volcan Lanin, compare the dark
exposed slopes to the white of the glacial ice.
Next week's picture: The Dancing Deer of Asia
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