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Patagonian Desert


The Patagonian Desert, also known as the Patagonia Desert or the Patagonian Steppe, is the largest desert in America and is the 7th largest desert in the world by area, occupying 260,000 square miles . It is located primarily in Argentina with small parts in Chile and is bounded by the Andes, to its west, and the Atlantic Ocean to its east, in the region of Patagonia, southern Argentina.

Geography and climate

The Patagonian Desert is the largest continental landmass of the 40 parallel and is a large cold winter desert, where the temperature rarely exceeds 12C and averages just 3C. The region experiences about seven months of winter and five months of summer. Frost is not uncommon in the desert but, due to the very dry condition year round, snow is. The Andes, to the desert's west, are the primary reason for the Patagonian's desert status as they inhibit the westerly flow of moisture from the southern Pacific from reaching inland. This creates a rain shadow that accounts for the formation of the desert and is why, despite approximately half of the desert being only about 200 miles from the ocean, such a large desert is found in the region. The cold Falkland Current off the Atlantic coast of South America also contributes to the area's aridity.

Before the Andes were formed, the region was likely covered by temperate forests. However, after the formation of the Andes, ash from nearby volcanoes covered the forests and mineral-saturated waters seeped into the logs, thus fossilizing the trees and creating one of the world's best preserved petrified forests in the desert's center. The Patagonian is mainly composed of gravel plains and plateaus with sandstone canyons and clay shapes dotting the landscape, sculpted by the desert wind. The region encompassing the desert, however, has many diverse features. Ephemeral rivers, lakes, and drainage deposits from the Andes' spring melt form annually, hosting a variety of waterfowl and aquatic grasses. A variety of glacial, fluvial, and volcanic deposits are also found in the region and have significantly affected the desert's climate over time, especially contributing to the gravel sediments covering parts of the Patagonian.

The desert is quite windy as well, a result of the rain shadow effect and descending cool mountain air. This wind helps make the Patagonian one of the largest, if not the largest, sources of dust over the South Atlantic Ocean.

Fauna and Flora

Despite the harsh desert environment, a number of animals venture into and live in the Patagonian. Some only live on the more habitable and geographically-varied outskirts of the desert, where food is more abundant and the environment less hostile, but all are found within the region encompassing the Patagonian. The burrowing owl, lesser rhea, guanaco, tuco-tuco, mara, pygmy armadillo, Patagonian weasel, puma, Patagonian gray fox, desert iguana, Jumping Cow Spider, and various species of eagle and hawk are a few of the variety of animals living in the region.

The flora of the region is quite common for its climate and includes several species of desert shrubs like Acantholippia and Benthamiella and tuft grasses like Stipa and Poa. Aquatic grasses and larger flora exist on the outskirts of the desert and around the ephemeral lakes that form from the Andes' runoff.

Human Influence

The desert has hosted various indigenous peoples in its past, as evidenced by cave paintings in the area. The area is sparsely populated today and those that do live here survive mainly by the raising of livestock such as sheep and goats. Resource mining, especially of oil, gas, and coal in parts of the region, is another way humans interact with and influence the desert environment. Poaching and hunting of some of the animals, like the various species of foxes, has further pressured the already fragile ecosystem.

See also

Patagonia

Desert

Rio Negro

Chubut

Santa Cruz

References

Gasso S. and Stein A.F., Does dust from Patagonia reach the sub-Antarctic Atlantic ocean? Geophys. Res. Letters, 34 (1): Art. No. L01801 JAN 3 2007.

Joseph R. McConnell, Alberto J. Aristarain, J. Ryan Banta, P. Ross Edwards, and Jefferson C. Simo, 20th-Century doubling in dust archived in an Antarctic Peninsula ice core parallels climate change and desertification in South America, Published online before print March 26, 2007, 10.1073/pnas.0607657104

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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Patagonian Desert


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