Terrane Tectonics AND GEOLOGICAL HISTORY of the North Cascades and San Juan Islands, Washington

TONY IRVING, University of Washington

August 7-10, 2003 in northwestern Washington and Seattle, Washington


            Note:  This course has a participant fee of $120 (in addition to the registration fee) to cover costs of van transportation, ferry fares, lodging and meals while at sites remote from Seattle.  Lodging in Seattle can be arranged at dormitories on the University of Washington campus or at nearby hotels for two nights, but costs are not included.  

Course Description

One of the most important corollaries of the concept of plate tectonics has been the development of a cogent explanation for the origins of the diverse rocks of western North America.  Prior to the 1970s, numerous geologists had mapped a bewildering array of rock formations in the region west of the Rocky Mountains without a satisfactory model for how these so-called terranes had come to be juxtaposed and assembled.  The solution to this geological puzzle continues to involve an integration of many diverse subdisciplines in geology, and collaboration among scientists who traditionally did not interact very much.  Fine examples of how tectonic analysis is applied can be found in a relatively small region of northwestern Washington.  We now understand that a series of small, unrelated lithospheric plates were docked and compressed against the North American continent about 200 million years ago when the large Wrangellia Terrane (now exposed on Vancouver Island and in Alaska) arrived.  The key rock formations are well exposed on the San Juan Islands, and furthermore can be correlated with other formations exposed in the mountains of the northern Cascade Range (often referred to as the North American Alps).

This 4-day program combines field expeditions to both the North Cascades and the San Juan Islands with classroom instruction and activities on the University of Washington campus to give educators a better understanding of how the complexities of ancient rocks can be unravelled and interpreted.  After an introductory campus session, participants will examine and discuss outcrops of the major terranes in spectacular mountain and marine island settings before returning to campus for further lecture and discussion.  Lodging and instruction during the 2-day field portion of the program will be at Skagit Valley College in Mount Vernon.  Topics to be addressed include: plate tectonics, stratigraphy, age dating, metamorphism, rock deformation, paleomagnetism, terrane accretion, and tectonostratigraphic correlation.

Suggestions about how to apply the information from this program to classroom activities and field trips in your own area will be included.  Limit: 20 participants. 

For college teachers of: all disciplines, but particularly natural sciences

Prerequisites:  none

Dr. Irving, currently a Lecturer in the Dept. of Earth and Space Sciences at the University of Washington, has extensive experience in college and public education in many aspects of geology.  He has taught numerous undergraduate and graduate classes in volcanology, petrology, mineralogy, geochemistry and historical geology.  During the past 22 years he has led many workshops for educators on the diverse regional geology of the Pacific Northwest.