Geography and Geology of the Galapagos Islands

Caitlin Dempsey


The Galapagos archipelago is located about 1000 kilometers to the west of Ecuador in the Pacific Ocean.

The Galapagos Islands are made up of over 125 islands, islets, and rocks that are home to a wide range of wildlife.

What Islands are in the Galapagos

The Galapagos is formed by 13 main islands: Darwin, Wolf, Pinto, Marchena, Genovesa, Fernandina, Isabela, Santiago, Baltra, Santa Cruz, San Cristóbal, Floreana, as well as countless islands (that here are not mentioned).

The islands cover a total area of 7,882 square kilometers.

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How Were the Galapagos Islands Formed?

The Galapagos Islands, like many other oceanic islands, are the result of tectonic motion of the layers beneath the surface.

Satellite image of the Galapagos Islands,  Source: NASA.
Satellite image of the Galapagos Islands, Source: NASA.

The mantel’s feathers are 100-kilometer-diameter columns of hot rock that rise from the Earth’s depths. Because of the high temperatures, these mantels rise (up to 200 centigrade degrees). The rock rises 10 cm per year on average.

As a result, the islands are the summits of volcanic cones, some of which are still active. Galapagos is one of the world’s most volcanically active areas, with 55 major eruptions recorded in the past, the most recent of which occurred in Marchena in 1991 and Fernandina in 1995.

Types of Islands in the Galapagos

The islands have two types of volcanoes.

In the west, on the islands of Isabela and Fernandina, we find large volcanoes that resemble soup plates or deep boilers.

Smaller volcanoes with less defined slopes are more common in the East. The thickness of the litospheric layer distinguishes these two types of volcanoes. Volcanoes in the shape of a plate of soup are unusual, and scientists are unsure of their origin.

Highest Point in the Galapagos Islands

Isabela has the highest point in the Galapagos Islands. Located on Isabela Island, Volcán Wolf, also known as Mount Whiton, has an elevation of 1,707 m (5600 ft).

(Because of the islands’ rich history, many volcanoes have two or even three names)

Biological Diversity of the Galapagos Islands

The Galapagos Islands are home to nearly 9,000 different species, many of which are rare and unique to the Islands. Giant tortoises, land iguanas, flightless cormorants, and the only penguin species found north of the equator are among them.


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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.