The Oregon Coast
Exotic Terrane, Geologically Speaking
Oregon’s coastal mountains plunge into the Pacific Ocean, creating wet temperate rain forests along the northern coastline. There you can walk the beaches observing ever-changing scenery as ocean fog rolls in off the Pacific, and coastal mist flows oceanward from the mountains. This back and forth opens up stunning views and just as quickly closes them again.
The road trip from Portland, Oregon, to the northern coast takes about ninety minutes. State Highway 26, aka Sunset Highway, is a popular route for a summer day at the beach. But take a jacket since 80 degrees F in Portland can often be 50 degrees on the coast. Slightly northwest of the city, you will find yourself on the winding roads of the coastal mountains, perhaps stuck behind a slow-moving truck. It’s a rugged, densely forested landscape, and you could be forgiven for thinking these mountains are part of the original North American Continent. However, they are not. Instead, they form what geologists describe as an exotic terrane, and they are, in essence, foreign land glued onto the edge of North America.
The core of the continent is a massive chunk of the earth’s crust referred to as the North American Craton. Craton is the terminology used to designate the geological core or nucleus of a continent. It constitutes a large, stable segment…
