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.  

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNsDvo_Yu55kuVDtxZRggZLOcvdgDvLVdOgFIzgzrkQwnr5tEDjWTZoTXCTzQJsEIwid4OFRUJH9YvK4RzDp21JL37fM02WqVxIjf0m2aqWCFkyB2ktRNDJ4yJx2BFK7gg0ypOzqtPW6M/?imgmax=800

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