Category Archives: Geology

Missoula Floods: This Was Once a Lake

Pasco Basin and Columbia River, Washington

This image was taken from the top of Saddle Mountain looking south toward the Pasco Basin. (Yesterday’s post was from the same location looking north toward the Othello Basin.)

Can you believe that this was once a 800 foot deep lake?  During the Missoula floods, water entered the Pasco Basin northeast from the Palouse, north from the Drumheller/Othello Channels and northwest from the Columbia River through Sentinel Gap.  Wallula Gap blocked the water from flowing freely through the Columbia Gorge to the Pacific Ocean.  The result was the temporary Ice Age Lake Lewis.  Today, the Columbia River meanders through the basin.  The Hanford Nuclear Research facility is located south and east of the river.  Rattlesnake Ridge is visible in the background.

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Missoula Floods: Facing Drumheller Channels

Drumheller Channels in Distance from Top of Saddle Mountain

This image was taken from the top of Saddle Mountain (~1,300 ft elevation) looking north east over the Othello basin toward the Drumheller Channels.  Imagine a wall of water 200 – 300 feet high racing over an 8-11 mile stretch over the Drumheller Channels at over 60 miles per hour.  This was the amount of water that was released (multiple times) when the Lake Missoula glacier dam broke releasing the water over the Eastern Washington basin.  Saddle Mountain broke the onslaught of water.  Some flowed west through the Crab Creek Coulee to the Columbia River and Sentinal Gap.  The remainder rushed around the eastern edge of the Mountain and into the Pasco Basin and Lake Lewis.

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A Day in the Canyon: Vertical Basalt Columns

Vertical Basalt Columns – Yakima River Canyon

A couple of miles up the road from my last post, I saw these basalt columns protruding vertically upward.  They were located on a different ridge.  The forces driving the uplift were different than the ones from the first ridge.  I ask why, what caused the difference? Did this ridge lift at a different time or were the forces just different from the ridge in the first post.  My curiosity kills me.  I think I need to do more research on how these “Yakima Folds” evolved.

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A Day in the Canyon: Tilted Basalt

Tilted Basalt Columns – Yakima River Canyon

This tilted basalt was the result of a plate fold being pushed up from a diagonal force.  Throughout the Yakima River Canyon the basalt columns show displacement in various directions.  This illustrates that forces were lateral pushing toward each other creating a “fold”.

The basalt shown here is in a “columnar” formation.  Basalt formed like this cooled very slowly, creating a soother texture.

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