Tuesday, November 14, 2006

Some Local Geology

McMurdo station is located on Ross Island. Ross Island is formed by three volcanoes: Mt. Erebus (see below), Mt. Terror, and Mt. Byrd. The area in and around McMurdo station is geologically governed by these volcanoes, and all the rocks here are volcanic in origin. Mt. Erebus is a stratovolcano, meaning that its cone is composed of layers of lava as well as layers of pyroclastic (or ejected) material. The majority of the rocks you see at McMurdo station are pyroclastic bombs, or tephra. In this case, the word “bombs” denotes size; they are the largest type of pyroclastic material.
Mt. Erebus, as seen from Observation Hill
The volcano is active, so you can see the gas/steam plume rising from the top.

A pyroclastic rock found near McMurdo. The holes you see are formed by gases during formation and ejection.

1 comment:

George said...

Is Mt. Erebus the highest mountain, or just the highest volcano in Antarctica? Do climbers ever attempt to summit it, or is it too active for that to be safe?