The Geology of Waikiki Springs

If you’ve spent a lot of time on the hiking trails of Spokane, chances are you’re well accustomed to the sight of basalt! However, you might not know what it is–basalt, as it turns out, is actually the memory of lava. This might seem unlikely. After all, here in Spokane, we’re about as far away from the Cascade Volcanoes as you can get in the state of Washington. While that might be true, it actually turns out the geology of much of the Northwest, from Oregon all the way to eastern Idaho, is shaped by volcanic activity.

The basalt you see on the South Rim today is a product of millions of years of lava flows pouring from the Pacific fault lines. Perhaps the most influential was the Grande Ronde Basalt flow, which lasted well over a million years and shaped the geology of the Columbia Basin for millenia to come.

Basalt columns aren’t the only rock formations you’ll see on the trails today! On Rattlesnake Ridge, keep an eye out for gneiss, a product of high stress and temperature being exerted on igneous rock (like basalt). When igneous rocks are exposed to high temperatures over long periods of time, they create visually striking ribbons of color that we call gneissic banding! Take a look on the trails and see if you can spot any of our region’s volcanic history in the rocks.