Surface Vulcanology

by Benjamin Kase 7/12/00
Sophomore Physiology and Neurobiology Major, College Park Scholars-Life Sciences

The Galápagos Islands are world renowned for the vast diversity of their flora and fauna. What most people are unaware of is the geologic significance of the archipelago. The islands are actually a series of volcanoes whose formation began around 8 million years ago. Many of the islands have since disappeared into the ocean because of plate movement and erosion. The islands remaining above surface ages range in age from 3.4 million to less than 750 thousand years old, with several still classified as active volcanoes (the last eruption occurring on Isla Fernandina in 1998). Though the archipelago was built primarily by one type of lava, there are notable morphological differences (such as contrasting topography) from island to island. On the northeastern end of the archipelago the typical island morphology is called a shield volcano. This type of volcano gets is name from its long flat appearance. On the southwestern end, the typical morphology is classified as an "inverted soup bowl." This volcano also gets its name from its appearance as a turned over bowl. Yet on each of these islands there are many other geologic characteristics of important significance:

  • General Volcanic Information
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  • Large Volcanic Structures

    There is also another general type of island morphology found in the Galápagos Islands. The Inverted Soup Bowl morphology is found on the "newer", or younger islands of the Galápagos.
  • Inverted Soup Bowl

  • Smaller Volcanic Structures


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    This smaller lava tube, one of the many that we observed on Bartolomé, is far more typical.
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  • Post Volcanic Structures




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  • Lava Types



    Hopefully this page has helped to organize and clearly explain the seemingly complicated surficial geology of the Galápagos Islands. The analysis began on a massive scale but progressively decreased in size eventually leading to a hand sample scale. Though the analysis could continue to investigate on a microscopic or even molecular level, such a process was regrettably beyond the scope of our expedition.


  • Additional Reading

    Monroe, James S. and Reed Wicander.Physical Geology: Exploring the Earth.West Publishing Company.:St. Paul,1995.

    Murck, Barbara W. and Brian J. Skinner Geology Today: Understanding Our Planet. John Wiley & Sons, Inc.: New York, 1999

    Rachowiecki, Rob. Ecuador and the Galápagos Islands. Lonely Planet Publications.: Australia, 1997.

  • Links

  • Galapagos Geology on the Web-Cornell University

  • Galápagos Vulcanology

  • Origin of the Galápagos Islands, A Photo Essay