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Geologic sightseeing

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.

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.

Link:
Oregon Outdoors
Travel Oregon Online - Willamette Valley
Silver Falls State Park

map legendCoastal RangeKlamath MountainsDeschutes-Columbia PlateauBlue MountainsHigh Lava PlainsCascade RangeWillamette ValleyBasin & Range & Owyhee uplandsBasin & Range & Owyhee uplands

Graphic by Elizabeth L. Orr, Geology of Oregon,
available from Nature of the Northwest


map legendaBlue MountainsWillamette ValleyDeschutes-Columbia plateauKlamath MountainsCoast Rangemap legendbCascade MountainsBasin Range & Owyhee uplandsHigh Lava plainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee UplandsCascade MountainsBasin & Range & Owyhee UplandsHigh Lava PlainsOwyhee Uplands


back to Geology sightseeing

Willamette Valley
Flood waters once stood 400 feet deep
in parts of the Willamette Valley about
15,000 years ago.

Silver Falls
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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800 NE Oregon Street, Suite 965, Portland, OR 97232-2162
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