Geologically the Andes are the mountain ranges that were formed under the Mesozoic tertiary era and they were the belt of the mountains in the rings of the pacific zones formed by the volcanic activity that encompasses the pacific rim.
These was created by the subconduction of the pacific ocean plate and that of the South American plate and resultant convergent plate resulted to the formation of this zone.
<u>These subcontracting plates are those of the Nazca and the antarctic plate and the orogeny of the plate is a result of the several orogenies of the late paleozoic periods that date back to that of the Pangea supercontinent.
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<u>Thus the plate is a subduction zone of the entire western coast of South America and has experienced several areas of volcanism.</u>
