GENERAL GEOLOGY

Detailed explanation-1: -The Andes were formed by tectonic activity whereby earth is uplifted as one plate (oceanic crust) subducts under another plate (continental crust). To get such a high mountain chain in a subduction zone setting is unusual which adds to the importance of trying to figure out when and how it happened.

Detailed explanation-2: -Geoscientists agree that a subduction zone offshore of the west coast of South America somehow promotes mountain building in the Andes. The oceanic Nazca plate dives beneath the South American plate, creating a trench in the seafloor and generating the compressive forces that build mountains.

Detailed explanation-3: -The Andes Mountains are part of the Southern Cordillera formed from subduction zone volcanism at the convergent boundary of the Nazca plate and the South American plate.

Detailed explanation-4: -The breakup of Pangaea dispersed these plates outward, and the collision of two of these plates-the continental South American Plate and the oceanic Nazca Plate-gave rise to the mountain-building activity that produced the Andes Mountains.

Detailed explanation-5: -Most of the Andes are located above the subducting Nazca plate except for the southern Andes, which are located above the subducting Antarctic plate. The mountains merge with ranges in Central America and the West Indies in the north, and with ranges in the Falklands and Antarctica in the south.