Mass Wasting and Erosion in the Galapagos

Much of the Galapagos is composed of volcanic rock.  Since the Galapagos has frequent volcanic eruptions, we must consider the effect of these eruptions on the land.

The Galapagos Islands are made up of a specific chemical composition that makes up its rock formations. The composition of these rocks is an important factor that determines the types of erosion that occur. 

The typical rock composition found in the Galapagos is basalt rock. Basalt rock, also called mafic rock, is found on the majority of the islands. These rocks are created by lava as it hardens.
                                                         
                                                           Photo: Basalt Rock

http://www.geol.umd.edu/~jmerck/GEOL388/images/03/basalt.jpg

Rock Formations:
Pinnacle Rock was formed when lava reached the sea which then created a phreatic explosion. The two extremes in temperatures (hot lava and cool ocean water) created an explosion and formed Pinnacle Rock. This type of land formation contributes to frequent additions to the islands.


                                                Photo: Pinnacle Rock

http://www.google.com/imgres?imgurl=http://www.photoseek.com/86GAL-10-16_Pinnacle-Rock-beach-Bartolome-Island.jpg&imgrefurl=http:

Additional factors are involved in shaping the rock formations that we see today in the Galapagos including erosion and mass wasting.

Factors that cause erosion:
1Wind
2Water
3 Ice
4 Gravity

                                       Wind can give new shape to existing rocks.  

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Phenomenons like Pinnacle Rock and wind erosion (seen above) highlight how the islands are in constant change.

Mass Wasting is the rapid downslope movement of angular slope material. (source, Mass Wasting of Slopes class notes). One example of mass wasting is slope failure which typically occurs in the Galapagos. The type of slope failure that most often takes place in basalt rock is a slump (also called a rotational slide). Slumps are common along river banks and sea coasts, where erosion has under-cut the slopes.  Heavy rains and earthquakes can also trigger slumps. All of these factors are present in the Galapagos leading to slumps that we see in the rock formations of these islands.

http://www.tulane.edu/~sanelson/geol204/masswastproc.htm

Volcanoes

Volcanoes in the Galapagos:

Volcanoes have played a huge role in the physical formation of the Galapagos. Consistent volcanic eruptions lead to island formation over time.

There are many factors that make the Galapagos unique. Below are some of the worlds volcanic hot-spots Hot-spots are located in the earth's mantle where magma is formed from volcanic activity.

                                         http://pubs.usgs.gov/gip/dynamic/world_map.html

Fernandina Island is the largest island of the Galapagos, which is home to La Cumbre Volcano. This volcano is still active and last erupted in 2009.

                                          Photo: La Cumbre Volcano

NASA images of the Fernandina Plume (NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center

The Cumbre Volcano is considered a Basalt Shield volcano. Basalt Shield volcanoes can be identified by their oblique shape. Other characteristics of shield volcanoes are their low gently sloping side. They are usually found at constructive or tensional boundaries.

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They are formed by eruptions of thin, runny lava. Eruptions tend to be frequent but relatively gentle.

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Frequent Volcanic Eruption Dangers:

The unique species of wild life and plant life that live on the Galapagos are one of a kind.  Volcanic eruptions often kill many plants and animals that only exist in the Galapagos. It's rare forms of species would be difficult to replace. Another long term impact of frequent volcanic eruptions is that it may affect tourism. The volcanoes of the Galapagos including La Cumbre are major attractions for tourism, which is a major source of revenue for these islands.