Basalt Formations


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What:  A dark igneous rock known as Basalt covers southeastern Washington. Any Lava with less than 53% silicon is known as Basalt and the lesser amount of silicon allows this lava to flow miles from its source creating a variety of scenery unparalleled in the world. Different cooling rates due to weather, proximity of water, and the volume of the flow cause a seemingly uncountable variety of type of structure. The slideshow above attempts to show some of this variety. The rock is frequently weathered reddish brown, varnished by bacteria to a dark black, or covered with algaes to hues of green, yellow, and red.  This massive substance that can easily be seen on nearly all east-west highways with its massive layers, fluted columns, and fractured faces, welled up from subterranean chambers to spread over vast areas in the northwest basin.

As I find what I feel are significantly differing examples of basalt formation I will post their pictures and any descriptions here.

When you look at these formations, it might help to think of water erosion tearing at smooth rock walls with varying densities. The weak stuff crumbles, the strong dense stuff remains.

Another interesting thing that basalt lava flows do is if something is covered with water before the lava covers it, the item is not always burned up by the lave flow because the water and the temperature of the item cools the lava around the item and a cast of the item is then made that makes a three dimensional picture of the item which can be studied millions of years later if the item is eroded. The item that has erosion take place to expose it is then rotted out and the cavity or cast is left of the item. I have photographic evidence of 2 instances of this happening in this area: Devil's Well and Blue Lake Rhino.

One form of basalt not pictured above is the ash form like that which fell on Spokane in 1980 from Mt St. Helens.

In New Zealand there is a unique formation of basalt. Click here to see pictures and read about it.

 Where:  Nearly everywhere east of the cascades in Washington State.



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