Geology of Patagonia | Patagonia Unbound

Patagonia is located at the southernmost tip of South America. The region includes the southern section of the Andes Mountains. To the east of this southern portion of the Andes are deserts, steppes, and grasslands. To the south are the ice fields and the climate grows colder. Patagonia has two coasts; a western one towards the Pacific Ocean and an eastern one towards the Atlantic Ocean.

The Colorado and Barrancas rivers run from the Andes to the Atlantic; these are generally considered the northern boundary of Argentine Patagonia. Tierra del Fuego, and sometimes the Falkland Islands are included as part of Patagonia. The Reloncavi Estuary is said by most geographers and historians to be the northern border of Patagonia on the Chilean side.  

For centuries Patagonia was known as the end of the world. It is not hard to imagine that you are indeed standing at the end of the world as you watch glaciers recede and break apart.


Patagonia Ice Fields


The ice field is an incredible phenomenon unique to the region. The massive ice feeds dozens of glaciers in the area. The glaciers going to the west flow into the fjords of the Patagonian channels of the Pacific Ocean. Those going to the East flow into the Patagonian lakes Viedma and Argentino, and eventually, through the rivers de la Leona and Santa Cruz, to the Atlantic Ocean.

An important part of the ice field is protected under different national parks, such as the Bernardo O'Higgins and Torres del Paine in Chile, as well as Los Glaciares in Argentina.

There are two known volcanoes under the ice field: Lautaro and Viedma. These are among the least researched volcanoes in Chile and Argentina because of how inaccessible they are.

The ice field has 28 exit glaciers. The largest two are San Quintin and San Rafael and they nearly reach sea level to the west at the Pacific Ocean. Smaller exit glaciers, like San Valentin and Nef, feed numerous rivers and glacially carved lakes to the east.

Patagonia Steppes


Patagonia is known for its steppes on the Argentine side of the region. These steppelike plains rise 330 ft in 13 terraces. The steppes are mostly bare of vegetation. Ponds or lakes of fresh and brackish water lie in the hollows of the plains. Towards the Andes animal life becomes more abundant and vegetation more luxuriant.

Patagonia Volcanoes


Patagonia is a geologist’s dream. Between glaciers, steppes, and volcanoes, Patagonia offers a little bit of everything.

The Andean Volcanic Belt runs through the southwestern part of South America. It is split up into four volcanic zones. The zone in Patagonia is known as the Austral Volcanic Zone or AVZ. The AVZ arcs from south of the Patagonian Volcanic Gap to the Tierra del Fuego archipelago, totaling a distance well over 600 miles (1,000km).

It is a volcanically active area though full blown eruptions are rare. Having said that, there were two major volcanic eruptions in 2015.

On March 3, 2015 Villarica erupted at 3am, spewing a stream of lava 3,000 ft. into the air. This symmetrical volcano sits on the shores of Lake Villarica. This area is a tourist hotspot, popular for hiking in the nearby hills and surrounding forests. The week before its eruption Villarica had been acting up. Over 3,000 people were evacuated from nearby towns including locals and tourists.

A month later on April 23, 2015 Calbuco surprised locals and experts with two eruptions in just a few hours. Calbuco had been dormant for decades and this volcano caught officials off guard. Ash smothered nearby towns and a plume of large smoke and ash could be seen from miles away. Over 4,000 people were evacuated in a 12 mile radius. Officials considered this eruption to be more serious than the one from Villarica the month before.

The volcanoes of Patagonia are not usually this active. Typically the area is popular among tourists for hiking, biking, mountain climbing, and even kayaking.