Oregons Geology An Intro to Geological Forces

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Oregons GeologyAn Intro to Geological Forces
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Coast Range

• Cannon Beach includes Tillamook Head (background)
  and 235 foot tall Haystack Rock
• Tsunamis - subduction zone earthquakes have
  buried tidal marshes in sand along the Oregon
  coast many times
• Devils Churn

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Dissolution of sandstone. Oregon coast.
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Erosion of sandstone Seastacks, Oregon Coast.
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Klamath Mountains

• Seastacks on coast were once part of an
  underwater reef complex.
• Oregon Caves is actually one cave, about 1,600
  feet long carved out of marble.
• Rogue River-Siskiyou National Forest

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Willamette Valley

• Erosion has carved large amphitheatersbehind
  North and South Falls that areaccessible by
  trail at Silver FallsState Park near Silverton.
• Flood waters once stood 400 feet deep in parts
  of the Willamette Valley about 15,000 years ago.

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Cascade Mountains

• Oregon Orbital View
• Crater Lake

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Mt. Hood
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Mt. Jefferson
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Mt. Washington
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Three Fingered Jack
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North Sister
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Middle Sister
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South Sister
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Mt. Bachelor
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Diamond Peak Mt. Yoran
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Mt. Thielsen
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Mt. Scott
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Mt. McLoughlin
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Deschutes-Columbia Plateau

• Formations of columnar basalt can be found
  throughout the Plateau.
• The Clarmo Unit of the John Day Fossil Beds

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Blue Mountains

• Blue Mountains
• Hells Canyon
• Wallowa Lake is the result of glaciation.
• Wallowa Mts were carved by nine glaciers during
  last two million years.

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High Lava Plains

• Paulina Lake, near Bend, is part of theNewberry
  National Volcanic Monument.
• Lava Lands Newberry
• Fort Rock in Lake County is the remains of an
  ancient tuff ring that formed in a violent
  explosion.

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Basin and Range and Owyhee Uplands

• Owyhee River travels in remote areas in the
  Northwest
• Steens Mountain is a huge uplifted block .
• Now seasonal, Alvord Lake once stretched a
  hundred miles north on the eastern edge of Steens
  Mountain.