Basalt columns - Spokane, WA
Posted by: 
T0SHEA
N 47° 38.578 W 117° 29.216
11T E 463427 N 5276733
These particular basalt columns were spied along West Sunset Highway north of I90 and northwest of the Spokane Airport.
Waymark Code: WMJHDE
Location: Washington, United States
Date Posted: 11/19/2013
Views: 13
These basalt columns themselves are rather unremarkable. However, what they are part of
is remarkable. Over the course of about 11 million years, ending about 6 million years ago, lava poured over the landscape in the Pacific Northwest, covering about half of Washington, and parts of western Idaho and northern Oregon. Most of this area of over sixty thousand square miles was covered with basalt to a depth of one mile. This is the largest outflow of lava to occur anywhere on earth.
When basalt cools it shrinks, causing it to break into more or less hexagonally shaped columns, much as large crystals. For close to 6 million years they slowly became covered with the detritus and vegetation that natural processes will cause to accumulate. Then, suddenly, after the last ice age, the failing of huge ice dams caused water trapped behind these dams to suddenly surge toward the sea. And there was a lot of water. This caused a sufficiently large flood to scour the land, once again exposing the upper portions of the basalt columns. These are what we all know as The Missoula Floods.
What we can infer from this is that, had it not been for these large floods, the elevation here would be somewhat higher, and it would likely have been pretty good farmland, given 6 million years of soil building.
These columns are extremely common in this area. They are used extensively for landscaping - they're seen throughout Spokane.
Great article on the subject here.
Parking coords are essentially the same as the waymark coords.
