Origin of Cascade Mountains?

Question

What is the origin of the cascade mountains in Washington and Oregon?

Answer 1

rock? granite? the origin=they are located in Washington...map? http://www.gonorthwest.com/Washington/cascades/map_cascades.htm volcano's have erupted there? http://academic.emporia.edu/aberjame/tectonic/cascade/cascade.htm

Answer 2

FORMATION OF THE MODERN CASCADES
1. Prior to formation of the Cascades, W. Oregon had been a deep marine basin with deltaic sedimentation (middle Eocene) on a coastal plain.

2. During the late Eocene, a volcanic arc complex erupted (~40 Ma) in central Oregon and north and south from this point.

3. Late Oligocene-earliest Miocene volcanoes of the Ancestral Cascades deposited major quantities of volcanic ash in Oregon.

4. Volcanism increased in late Oligocene, basaltic flows form lava plateau.

5. By the end of the Miocene a high region with a variety of eruptons.

6. Increased uplift and composite volcano building during the Pliocene-Holocene, frequent eruptions built modern peaks which have been modified by glaciation.

CAUSE
1. Deepening of Laramide suduction of Farallon Plate initiates arc volcanism

2. Subduction of Juan de Fuca Plate (remanent of Farallon Plate) under the North American Plate at 1 1/2 inches/year causes the modern Cascade volcanism to begin about 4 mya.

3. Volcanism shuts off from south to north as the transform boundary migrates northward. Note: Mt. Lassen is just north of the shut-off zone.

Answer 3

The development (growth, or uplifting) of the Cascades has nothing to do with the weather, and everything to do with Plate Tectonics and volcanism. There is a complex pattern of movement of plates in the area or nearby. Weather plays a major part in erosion, of course, which has the opposite effect of uplifting and volcanism. This is geological, and I would personally think that palaeontology would be restricted to fairly recent times, geologically speaking. But I could be wrong.

Answer 4

There are fault lines running along the plates of the earth surface. when the edges are pushed together, one generally rides on top of the other and gets pushed up to forms hills and mountains. If you check, the layers of rock will not be horizontal, but nearly virtical.