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Sneak Peeks from Frenchman Coulee

Greetings from the dry side! B and I crossed the Cascades in search of lotsa lava for you, and we found plenty. Here’s a sneak peek! There’s a delightful juxtaposition between fire and water over here.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Greetings from the dry side! B and I crossed the Cascades in search of lotsa lava for you, and we found plenty. Here’s a sneak peek!

There’s a delightful juxtaposition between fire and water over here. First, you’ve got yer Columbia River basalts, which are one of the world’s great large igneous provinces. Fifteen million or so years ago, basalt poured out of rifts in the ground right around the Washington-Idaho line, and flooded ginormous parts of the state.

Fast forward to around 10,000 years ago or so, when the Cordilleran Ice Sheet was nosing down from Canada, damming the Clark Fork River and creating a mega-sized lake. There’s a good reason ice dams are a terrible idea: water floats ice. Every time the water backed up to a great enough depth to make the ice dam float, mind-boggling amounts of water gushed out and hurtled toward the sea, scouring the land down to basalt bedrock, and ripping up great chunks of that bedrock when the momentum slowed. Oh, look, here’s one of those chunks now!


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I was so excited to finally make it to Frenchman Coulee and Babcock Bench – I’ve been meaning to get out there for years. I’ll have lots more awesome pics for you soon, and we’ll be getting our hot LIP action very soon – after pyrite, o’ course, geological disasters in the world allowing. And I’ll bring you some sneak peeks from Day 2 as soon as we get back home. In the meantime, check out the post that made me yearn for Babcock Bench all those years ago. Enjoy!