Category Archives: Geology

A Perspective of Time

Argillite Boulder – Rattlesnake Mountain, Washington

This image depicts an interesting perspective of time.  The rock in the foreground was deposited here on Rattlesnake Mountain around 15,000 years ago.  The Rattlesnake Mountain and the Horse Heaven Hills in the background were created as part of the Yakima Fold formation about 1.5 million years ago.  The bedrock of this area is basalt from basalt flows through eastern Washington from 6-15 million years ago. The argillite boulder in the foreground is metamorphic rock from western Montana formed 1.5 billion years ago.

So here I was, sitting on a rock created before life on earth existed, brought here by a humongous flood around 15 thousand years ago, deposited on mountains uplifted 1.5 million years ago, created by a series of gigantic lava flows about 2 miles thick 6-15 million years ago.  And I think I am old at 67 years. As many of my Whizzy friends would say, “It’s a thinker.”

What is a Bergmound?

Bergmound – Rattlesnake Mountain, Washington

As glaciers moved southward during the Ice Ages, they scoured the terrain picking up rock debris.  During the Missoula Floods, parts of the glaciers would break off forming ice bergs.  These were carried down through the Eastern Washington scablands into the Pasco basin.  As Lake Lewis formed, many of the ice bergs floated to the edges of the lake.  As the lake emptied, several of these ice bergs were left stranded on the surrounding ridges.  They melted leaving mounds of accumulated rocks, gravel, and sand. These are “bergmounds”.

Most bergmounds are found in the Pasco Basin at elevations of 600 – 850 feet.  They are 20 – 35 feet higher than the surrounding terrain.  The bergmound pictured above is on a plateau of eastern Rattlesnake mountain above Richland, WA.  The bergmounds are somewhat inconspicuous unless, one is looking for them.

Granite Erratic

Granite Erratic – Rattlesnake Mountain, Washington

The Missoula Floods carried large icebergs from the glaciers that dammed Lake Missoula or from the Okanagan lobe glacier that dammed Lake Columbia along with them as they made their way to the Pacific.  As the icebergs melted or became “stranded” against ridges that formed Lake Lewis, they dropped the rocks that the glaciers picked up as they scoured their paths southward.  Granite is present in Montana as well as northern Washington.  But it is not present in central Washington.  The origin of this single granite erratic on Rattlesnake Mountain is therefore not definite. It could have come from either Montana or northern Washington.

This chunk of granite is approximately 6′ in length.  It is located at about 800 feet elevation (my estimate).

Giant Ripples

  • Giant Ripples on the West Bar – Columbia River

This image is a close-up of the giant ripples on the West Bar near Crescent City on the Columbia River as showed on my previous entry.  These giant ripples were created during the Ice Age Floods as the Columbia River flowed over the gravel bar.  They are 35 feet high, spaced at 150 -200 feet apart.  It is amazing what water can do!

The Calm Columbia

Columbia River – West Bar

How calm the Columbia River looks.  Fifteen thousand years ago, during the Ice Age Floods,  it wasn’t quite like this.  At that time the Columbia was flowing at the top of the basalt cliffs seen in the distance.  The West Bar shown in the middle of this image is comprised of gravel. rock, and other sediments.  It was part of the backwater created as the Columbia raged toward the left and then back down through the gorge. The surface of the bar is covered with giant ripples around thirty feet high.

This image was taken above Crescent Bar looking southwest.

Sentinel Gap on Columbia River

Sentinel Gap Looking South from Frenchman’s Spring Coulee

This image was taken from the bottom of Frenchman’s Spring Coulee near where it enters the Columbia River.  Sentinel Gap was cut across the Saddle Mountains by the Columbia River and the Ice Age Floods.  During the floods, the Columbia River was at a level near the top of the eastern slope of the Gap.  On the north side of the Gap, the Vantage Bridge and Wanapum Dam are faintly visible.  Through the Gap, Umatilla and Rattlesnake Ridges are visible.  And of course, the clouds make the image.


Frenchman’s Spring Coulee

Frenchman’s Spring Coulee – near Vantage, WA

This image is taken from the top of the Frenchman’s Spring Coulee looking down toward the Columbia River.  The mountains in the far background are the Cascade foothills. This coulee was created during the Ice Age Missoula Floods.  It is the farthest south water path from the Quincy Basin to the Columbia River.  The flood waters in the Quincy Basin were split by the Frenchman hills, just south of this coulee.  The water flowed east into the Drumheller Channels toward Othello and west into the Columbia River via several coulees including Frenchman Springs.

The wind was howling, so I did not feel like getting too close to the edge.  I bet this will make a good sunset or sunrise photo.  I will be back.


Drumheller Channels Pano

Drumheller Channels – Othello, Washington

This image is a hand-held pano taken above the Goose Lake trail head at the northern part of the Drumheller Channels reserve, just below O’Sullivan Dam.  This was our final stop on our Sandhill Crane photo shoot.  We took a leisurely hike (walk) to cap off a great trip.  Spring is a beautiful time to visit the Channels.  I was hoping for some big white puffy clouds.  But it just did not happen this trip.  I will return …

More Ice Age Geology – Corfu Landslide

Corfu Landslide – Saddle Mountains, Central Washington

This image was taken from  Lower Crab Creek Road.  It is a small section of the Corfu Landslide. Lower Crab creek is in the foreground. This part of the landslide was probably post Missoula Floods.  It looked like the rocks at the base were not eroded, hence it probably occurred following the last floods.  The land slide extends upward to the Saddle Mountains crest.  A couple of weeks prior to taking this image,  I was at the crest of the Mountain looking down.  Refer to my post of 27 March.

Drumheller Channels: Missing a Tooth

Drumheller Channels – Othello, WA

The first thing I thought of when I looked up and saw this section of columnar basalt was that it was missing a tooth.  Columnar basalt is very susceptible to water erosion because of its many fissures.  The raging water of the Missoula Floods easily plucked the columns from their path.