Download Assignment 6

Geology 103
Name:
Assignment 6: Plate Tectonics and the Pacific Northwest
Due: Wednesday, May 21
Go to the Northwest Origins page at the Burke Museum of Natural History and
Culture site to answer the following questions.
http://www.burkemuseum.org/static/geo_history_wa/index.htm
0. What are the authors’ names for these pages? When did they write it?
1. When the supercontinent Rodinia broke up, what kind of margin was western
North America? How much of Washington was above sea level? What two
rocks are evidence for this?
2. As the supercontinent Pangaea broke up, what kind of margin was western
North America? Describe the tectonic interaction that was occurring here, and
name the plates involved.
3. What is a “terrane”? Why are these important to the story of western North
America? From oldest to youngest, what are the terrane names that build up
Washington? What are the terranes made of?
4. In addition to terrane accretion, what other tectonic event happened during
those accretionary periods? What rock still exists from this event?
5. Which of the four “episodes” described on the site fits the timing and
lithology of the Eocene rocks of western Washington?
6. During that “episode”, what kind of tectonic interaction was going on in the
Pacific Northwest? Name the plates involved.