Geology | Galapagos Unbound

Geology

ECUADOR: THE LAND OF ICE AND FIRE

Ice and fire: a combustive combination well known to Ecuadorians who have seen their country repeatedly transformed, devastated, and brought alive by the geologic forces constantly churning beneath the earth and ocean crusts. Ecuador is replete with geology:  immense glaciated mountains and volcanoes remain sentinel over the country since the Pleistocene era; plateaus and valleys lend way to Amazonian rainforests; and coastline stretches down the west and looks over the Galápagos islands. The country is sure to ensnare anyone interested in geomorphology or anyone simply fascinated with the wonders of nature.

 

ECUADOR’S GEOLOGIC COMPOSITION

With the Andes Cordilleras trisecting Ecuador, the country provides various habitats that are each unique and incredible in their own right. With such geologic differentiation, it is little wonder that Ecuador is one of the world’s leading contenders in biodiversity per square kilometer.

Two Andean Cordilleras—the Western, or Cordillera Occidental, and the Eastern, or Cordillera Real—lie within the relatively small country. The two cordilleras partition the continental terrain into three regions: the Inter-Andean Corridor, or la Sierra; the Oriente, or Amazonian jungle; and la Costa, or the coastal lowlands along the Pacific. Of course, the Galápagos Islands are counted as Ecuador’s fourth geographic region although it lies off its shores.

Ecuador’s Cordillera Real also serves as the cornerstone to the South American Andes, traveling the continent from the Tierra de Fuego down to the Caribbean Sea. Though the continental chain is rather lengthy, Ecuador boasts of more reachable peaks than anywhere else the cordillera travels.

Perhaps of more interest is the Cordillera Occidental, which covers territory from the Gulf of Guayaquil to Colombia in the north. The Cordillera Occidental originates from the sea as it was formed when the Pacific Ocean’s ocean floor and marine crust—as well as the underwater cordillera known as the Macuchi Island Arch—converged with and were uplifted against the Cordillera Real. The Cordillera Occidental is also endowed with three impressive caldera volcanoes: Quicocha, Pululahua, and Quilotoa.

The Napo Uplift is also responsible for Ecuador’s unique geologic situation. The Napo Uplift is an elevated continental block found in the north Oriente that is an autonomous tectonic feature from Ecuador’s two other cordilleras. The Napo Uplift holds another two volcanoes, the Reventador volcano and the Sumaco volcano. The Reventador lies in the Oriente region and remains the Oriente’s easternmost active andesite volcano. Sumaco lies to the south of Reventador and as an alkaline volcano differs in lava composition. The geologic process involved in the uplift is responsible for a significant portion of Ecuador’s volcanic activity.  

 

GEOLOGIC HISTORY

Geologists estimate that South America was joined with the African continent around 150 million years ago before beginning the split from Africa in the mid-Cretaceous period around 100 million years ago. Over time, the western tectonic movement of the South American plate brought it into a collision course with the Pacific plates. This resulted in the uplift of continental rock that ultimately formed the Andes that run along South America’s western edge. The portion of the Andes that travel through Columbia and Ecuador are comparatively younger than the southern portion of the mountain range.

In relation to the volcanic activity riddling much of South America’s formative years, the volcanic activity resulting in the Galápagos Islands occurred recently—at least geologically speaking. Geologists estimate that while portions of the islands date back to 3 million years ago, some formations have only occurred over the last 1 million years, which make the islands very young indeed. Like other archipelagos such as the Hawaiian Islands, the Galápagos Islands were formed by volcanic activity deep under the earth’s ocean crust. Eruptions producing magma emitted from weak spots, otherwise known as hot spots, in the crust produce volcanic, oceanic archipelagos such as the Galápagos.

This tectonic movement has also resulted in a high amount of volcanic activity over the course of Ecuador’s geologic history. Ecuador is largely comprised of volcanic terrain, whereas the Galápagos Islands are entirely volcanic. The high number of volcanoes and continual volcanic activity is caused by the subduction of the Nazca Pacific oceanic plate under the South American continental plate. Although the volcanoes within Ecuador are part of South America’s Northern Volcanic Zone, within Ecuador itself the volcanoes have manifested in four distinct chains.

Perhaps the most famous string of volcanoes included in Ecuador’s terrain is the Ring of Fire, which follows the Pacific Ocean’s edges. The Ring of Fire is responsible for 90% of the world’s earthquakes, and its string of volcanoes includes 75% of the world’s active volcanoes. Although Johnny Cash wasn’t singing about the dynamic world of volcanoes, it’s easy to fall in love with Ecuador’s own still-burning Ring of Fire.

 

THE AVENUE OF VOLCANOES (Avenida de los volcanes)

During an 1802 expedition to South American, German explorer Alexander von Humbolt came upon a region in the Ecuadorian Sierra riddled with high summits and volcanoes. He dubbed the region “The Avenue of the Volcanoes,” an honorific that has lasted to this day. The Avenue of the Volcanoes travels along a 200 kilometer path between the Eastern and Western Cordilleras, a route which offers various opportunities to view fourteen of Ecuador’s volcanoes. These omnipresent witnesses of history are impressive to look at and humbling as well, for they formed much of Ecuador even as they hold the power to change it forever.

Cotopaxi

Cotopaxi stands high of 5,897 meters, making it the world’s highest active volcano. The glaciated summit and its surrounding terrain comprise the Cotopaxi National Park. With its imposing and impressive geological landscape, as well as its impressive elevation, Cotopaxi is favored as Ecuador’s favorite climb. It’s also readily distinguishable by its practically symmetrical cone that rises solidly above a highland plain.

In September 2015, Cotopaxi experienced its first major eruption since 1877. Prone to fast-moving mud flows and ash discharges, Cotopaxi has become known as one of the world’s most dangerous volcanoes. Its mud flows are a concern due to its glacier cover, which melt the ice caps. The 1877 eruption and subsequent mud flows devastated the neighboring town of Latacunga. Ash from the most recent eruption reached the Pacific Ocean, and earthquakes tremored the local communities and nearby national park. However, the rumbling volcano has not wreaked as much havoc as its last eruption as of yet.

 

Volcán Cayambe

Located in the Pichincha province and Ecuador’s Cordillera Central, the volcano Cayambe is Ecuador’s third highest mountain. The volcano is composed of consecutive lava domes formed on top of a previous, extinct volcano. Cayambe has a glaciated summit that’s the only summit in the world traversed by the equator. In fact, this glaciated summit is the equator’s only snow-capped mountain. With its snow suffused environment, Cayambe also earns the prestige of the coldest place on the equator. If you not only feel like a heady climb up a volcano but some respite from the South American heat, Cayambe is the volcano for you.

 

Tungurahua

Tungurahua translates to “Throat of Fire” in Kichwa, or Quichua, the language of the Incas. Nowadays, many people refer to it simply as “Mama.” Tungurahua gained its fiery name as a stratovolcano that was formed from three significant volcanic developments. Geologists refer to three installments of the volcano numerically as the initial edifice collapsed, as did a second constructed edifice until the Tungurahua III came about. With Tungurahua’s explosive history, it is not surprising that it remains one of South America’s most active volcanoes. The volcano continues to be characterized by its ash explosions and pyroclastic flows. As of 2000, the summit’s crater has also been showing signs of evolving a new lava dome.  

 

Chimborazo

Chimborazo is the highest mountain in Ecuador with a peak elevation of 6,268 meters—a peak elevation that also makes it the highest peak found near the equator. While this elevation does not make Chimborazo a prize compared to other mountains when considering elevation above sea level, its position at a point on the equatorial bulge allows for the summit to gain the fame of representing the farthest distance from the Earth’s surface to the Earth’s center.

 

Pichincha

The Pichincha volcanic massif rises above Quito’s foothills and is comprised of the Guagua Pichincha Volcano as well as the Rucu Pichincha. The Guagua Pichincha is a stratovolcano that lies 9 km west of Quito, whereas Rucu lies 1 km further west. Ecuador’s indigenous people must have read into their distance from Quito as being indicative of their age, as Guagua means “baby” while Rucu means “old” in Quichua. Fittingly, Rucu is no longer active while Guagu has taken over the volcanic lead.

Pichincha is another of Ecuador’s most active volcanoes with 25 eruptions under its belt. With its most recent eruptive activity being in 2008, Pichincha is very much an active force in Ecuador. Guagua Pichincha is also prized by the Ecuadorians as a historic site as Quito’s independence from the Spanish was won in its foothills.