Andes Mountain Range
Being the proud owners of three chinchillas (a mom and her
two babies), my daughters and I decided to take an adventurous trip to learn
more about their native location, the Andes Mountains in South America.
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| Chinchilla babies - Snowball and Sophie |
The Andes Mountain range is the longest mountain range, spanning
5,500 miles from Venezuela along Chile to Southern tip of South America, crossing
through seven countries; Venezuela, Colombia, Ecuador, Peru, Bolivia, Argentina
and Chile.
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Map of Andes Mountain range
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As we climbed the amazing mountain peaks, observing
chinchillas in their natural environment, my daughters asked our guide how this
amazing mountain range was created. Our guide explained that the Andes mountain
range was the result of two of the Earth’s plates colliding at a convergent plate
boundary. Specifically, the Andes are the result of an oceanic plate crashing
into a continental plate, otherwise known as convergent plate activity. As
illustrated in the picture below, when an oceanic plate and a continental plate
collide, the denser plate pushes downward under the lighter plate. This process
is called subduction. As the denser plate (in this case the Nazca plate) subducts
under the lighter plate (in this case the South American continental plate), a deep
marine trench is created. As the Nazca and the South American plates collided, folding
at the surface occurred due to the compression and squeezing of the surface
rocks; shortening the Earth’s crust horizontally. At the same time, beneath the
Earth’s surface, as the Nazca plate created friction and continued to push
under the continental plate, earthquakes resulted. Volcanoes also resulted from the heat
generated as the Nazca plate pushed downward causing a partial melting and
creation of magma which was released in explosive volcanic activity. The Andes
Mountain range is home to almost 50 volcanos in total.
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Oceanic to Continental Plate Convergent Activity
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As we hiked, our guide pointed out that the range is made up
of a variety of rocks due the expansiveness of the range. Extrusive igneous rocks
are present in the mountain range due to the extensive volcanic activity. The Andes
are known for andesitic rock which presents itself in a viscous form below the Earth's crust, resulting
in explosive volcanic activity. There are also sedimentary rocks present in the
Andes due to the plate moving and dragging of rocks along with the movement
from other locations, commonly found with thrust faults.
The compression and subduction of the plate collision, resulting
in the folding of surface rocks, earthquakes and volcanism (lifting) together permanently
deformed the Earth’s crust, creating the beautiful landscape and home to
chinchillas; the Andes Mountain range.
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Southern Andes
https://kids.britannica.com/students/assembly/view/159031
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