Showing posts with label Patagonia. Show all posts
Showing posts with label Patagonia. Show all posts

Tuesday, May 3, 2011

Patagonia

Glaciers are found in Patagonia near the Andes Mountains.   

Along with bringing in tourism to Argentina, the glaciers provide water
for drinking and irrigation for the communities that live nearby. 

Despite global warming, Argentina's Perito Moreno glacier is
one of the few icefields that has withstood rising global temperatures. 

 

Glaciers form in the accumulation zone and begin to move across the surface by 
internal deformation and basal slip. In the ablation zone, glacial ice is 
lost due to calving, melting, and sublimation. 

Figure 1. The video below shows glacial ice calving from the "Perito Moreno Glacier."


U-shaped valleys are formed from erosion as the glacier ice moves through the floor of the valley, smoothing and plucking rocks. Aretes are knife-like ridges that can usually be seen on the sides of a glacial trough.

Figure 2. This picture shows a U-shaped valley in Argentina formed by a glacier. 
http://www.google.com/imgres?imgurl=http://glacierchange.files.wordpress.com/2010/12/glaciar_seco_chica2.jpg

 Figure 3.  Drumlins are seen running parallel to each other in Patagonia
after being formed by bed deformation beneath the ice sheet.
http://www.google.com/imgres?imgurl=http://farm1.static.flickr.com/193/484490627_f64b7686fb.jpg


Figure 4.  Many kettle lakes can be found in the outwash plains of Patagonia.
 http://www.google.com/imgres?imgurl=http://farm4.static.flickr.com/3594/3448102248_c447cc3d29.jpg

Figure 5.  Kettle lakes are formed when a block 
of buried glacial ice in the outwash plains melts

http://www.google.com/imgres?imgurl=http://pbisotopes.ess.sunysb.edu/esp/Science_Walks/carmans/kettle-hole.gif

When till (mixture of boulders, gravel, sand and clay) is left behind in the ablation zone by the glacier, moraines are built on the sides and middle of the glacier. 

Figure 6. Several people hike the lateral moraine of Perito Moreno Glacier.  
http://www.google.com/imgres?imgurl=http://farm6.static.flickr.com/5263/5566180523_86dbecc3d2.jpg


When accumulation of ice is equal to ablation, 
the front is stable and a terminal moraine is built.  

Figure 7. This picture shows a terminal moraine of "Perito Moreno" 
along with many glacial crevasses.


http://www.google.com/imgres?imgurl=http://cache2.allpostersimages.com/p/LRG/54/5480/EONKG00Z/posters/oxford-pete-perito-moreno-glacier-and-terminal-moraine-los-glaciares-national-park-argentina.jpg

 As a glacier melts, streams form in front and deposit outwash.

Figure 8.  This alluvium is carried by meltwater streams far into the outwash plains.  
 http://www.destination360.com/south-america/argentina/patagonia



As a result of glaciers, fluvial landscapes surround the Andes Mountains. 
As a meandering river's amplitude increases, deposition occurs on 
the inside of the river bend while the outside cut banks are eroded. Overtime 
as the erosion continues on the outside of the river bend, the river shifts course. 

Figure 9.  Taken from space with remote sensing, the Rio Negro in Argentina 
demonstrates alterations of the meandering channel within its floodplain. 

http://rst.gsfc.nasa.gov/Sect17/Sect17_4.html

Works Cited
http://news.mongabay.com/2005/0907-wwf.html
http://www.msnbc.msn.com/id/31363631/ns/us_news-environment/
http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/glacial_systems/glacier_movement.html

Tuesday, February 15, 2011

The Andes Mountains

Patagonia is a main attraction for the tourists, and a home for the locals in Argentina.  Surrounded by glaciers and volcanoes, this vast region is found in the Andes Mountains.  These mountains were formed by the process of convergence and subduction.  In these processes, ocean crust (composition of basalt) collided with continental crust (composition of granite).  As a result, the Andes mountains were thrust upwards from the oceanic and continental plate's collision.

 http://cartinafinland.fi/en/imagebank/image/84/84223/Andes%2Bmountains,%2BArgentina.%2B84223.jpg&imgrefurl


      The Andes continue to grow as the lithosphere begins "rafting" on the asthenosphere.


                         Caption:  A aerial view shot of Patagonia taken from Chile.

http://en.wikipedia.org/wiki/File:Patagonia_aerial.jpg



Caption:  The picture above shows a fault-line scarp of a normal fault in the Andes.

This normal fault was formed by the process of extension.



http://www.google.com/imgres?imgurl=http://ic.ucsc.edu/~casey/eart150/Lectures/3NormStrkSlpFlts/AndesNrmlFlt.mod.jpg&imgrefurl




The Copahue Volcano below is an active stratovolcano.  It is composed of andesite and has a composite cone with a caldera of twelve miles in diameter.  Since this volcano is near a lake, many geysers exist due to the geothermal activity.  During an eruption, this stratovolcano expels lava with high viscosity.  In the last eruption of Copahue, pyroclastics such as tephras, cinders, and bombs were emitted.  Being near the eruption, locals and tourists inhaled this dangerous ash.  With this volcano surrounded by snow, it is probable that there were lahars.




http://travellingboard.net/wp-content/uploads/2008/06/copahue.jpg

Caption Below:  The video below gives a great 360 degree view at the solfatara field of the Copahue volcano and shows numerous, basalt-lava flows and dikes.


http://www.youtube.com/watch?v=SdwU3QGWtWg&feature=player_embedded#at=13




Caption Below:  A great example of isostatic balance is shown in the glaciers near Patagonia.





http://www.google.com/imgres?imgurl=http://portraithouse.net/wp-content/uploads/2010/01/Perito_Moreno_Glacier_Patagonia_Argentina_Luca_Galuzzi_2005.jpg&imgrefurl


            As the glacier recedes and the ice melts, the crust (lithosphere) shows isostatic rebound.           


               Below: Perito Moreno Glacier


http://www.google.com/imgres?imgurl=http://www.hostelbloggers.com/wp-content/uploads/2008/08/argentina-perito_moreno-glacier.jpg&imgrefurl


Works Cited
http://www.patagonia-argentina.com/i/
http://www.blueplanetbiomes.org/andes.htm
http://volcano.oregonstate.edu/vwdocs/volc_images/south_america/chile/copahue.html
http://www.volcanolive.com/copahue.html
http://science.jrank.org/pages/6300/South-America-Andes.html
http://www.wesleyan.edu/ees/JCV/vlsa1.html