Geological Features of Mt. Rainier

Mount Rainier geological make up is both that of fire and ice, which is a combination of both volcanism and glaciation. Being affected by both fire and ice has drastically contributed to the volcanoes transformation in appearance since its existence. Approximately 5700 years about the summit of Mount Rainier was destroyed due to a violent explosion that resulted in large pieces of both glacier and rock being launched miles away. This explosion caused mudflows to burn down the valleys. This violent explosion created caldera, which occurs after a violent volcanic explosion and results in a large basin.  After all the commotion of the explosion was over it wasn’t long before the glaciers were able to rebuild themselves. The rebuilt glaciers once again began the erosion process, yet it wasn’t until thousands of years later that the summit was rebuilt due to ash falls and lava flows. Although a new cone could be created, lava continues to over then cone and create vents. The map below shows a map of these lava flows and the glaciers that make up Mount Rainier. 

Map of Mount Rainier Lava flows and Glaciers
(Decker, and Decker)
 

Even though Mount Rainier remains to be an active volcano, an extraordinarily large portion of its’ eruptions are attributed to lava flows and only 10% of its’ eruptions being pyroclastics. (Harris, Tuttle, and Tuttle 513-514)

Information and pictures from this post are credited to the following sources:

Harris, Ann G., Esther Tuttle, and Sherwood D. Tuttle.Geology of National Parks. sixth ed. . Dubuque,Iowa: Kendall/Hunt Publishing Company, 2004. 513-514. Print.

Decker, Robert, and Barbara Decker. "Dartmouth." Road Guide to Mount Rainier National Park. Double Decker Press, 1996. Web. 18 Feb 2012. <http://www.dartmouth.edu/~volcano/texts/DekRainier.html>.