| Learn More About Oregon's Geology |
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Willamette Valley
The Willamette Valley province forms a catch basin between the Coast Range and the Cascades. The sediments collected into this basin record multiple Ice Age floods that originated in Montana, poured through the Cascades (via the Columbia River), and backed up in the valley before eventually draining to the Pacific Ocean. |
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| Flood waters once stood 400 feet deep in parts of the Willamette Valley about 15,000 years ago. |
Erosion has carved large amphitheaters
behind North and South Falls that are accessible by trail at Silver Falls State Park near Silverton. |
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Silver Falls State Park,
located on Highway 214 east of Salem: A 7-mile hiking trail takes you near or behind 10 waterfalls which cascade over steep cliffs of Columbia River basalt that flowed into this area as molten lava 14-16 million years ago. At North Falls, chimney-like holes in the overhanging rock are tree molds formed when hot lava flowed around and over standing trees. |
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