Northwest US Cascade range geology

From: Eigenvector (m44_master_at_yahoo.com)
Date: 12/13/04 

Date: Sun, 12 Dec 2004 20:25:45 -0800

As an avid hiker living in the Seattle area, I've covered quite a bit of the
Cascades. I'm curious as to how the range itself formed. The volcanoes are
obvious, but what about the surrounding peaks? From how I see it as a
hiker, you have a series of small broken mountains (5 to 6,000 feet in
height) with a couple three massive volcanoes here and there. Where did the
small mountains come from? Was it from the local plate getting pushed up?
Are they volcanes themselves? Are those mountains the remnants of previous
volcanoes (tummulus I think I heard it called)?

Are the Olympics part of the same mountain chain, with Vancouver Island
thrown in there for good measure - separated from the main range body by
some other techtonic process?

The area is facinating to me, very rugged in a very narrow band, with huge
flat basaltic seas on one side and the ocean (well a strait anyway) on the
other.

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