- What does it mean to be curious?

For my students, (cheerful music) curiosity creates opportunities for a bigger and brighter future.

(logo chimes) (upbeat music) - Have you been to Beacon Rock in the Columbia River Gorge?

You can walk all the way to the top of this thing.

It's more than 800 feet tall.

But are you aware that Beacon Rock used to be taller when it was a volcano erupting here in the gorge during the Ice Age?

(upbeat music continues) (water rustling) Welcome to Beacon Rock State Park on the Washington side of the Columbia River Gorge.

This monolith was named Beacon Rock by Lewis and Clark, who paddled down the Columbia River in the early 1800s, but they didn't know it was a volcano.

We now know that Beacon Rock was a cinder cone volcano that grew here inside of the gorge 57,000 years ago during the Ice Age.

And yet, when you climb to the top of Beacon Rock, there are no cinders anymore.

What happened to the red cinders of the Beacon Rock cinder cone volcano?

(upbeat music) (footsteps crunching) So Beacon Rock was a cinder cone volcano.

That doesn't look like a cinder cone to me, does it to you?

These are big, beautiful sheer walls of black basalt rock columns.

And yet when this cider cone was intact during the Ice Age, it was composed of red cinders on the top and on the sides.

Lots of these red cinders.

That's what a cinder cone volcano is.

These particles are full of holes, meaning gas was part of the cider cone eruption.

And these things are flying through the air from the volcanic vent, like popcorn flying through the air away from a hot air popcorn popper.

That's the cinder cone story, and yet the cinders are gone.

And these rock columns are very similar to other basalt rock columns throughout the Columbia River Gorge.

What's the difference?

(mysterious music) So it turns out there's two basalt stories here.

The basalt of Beacon Rock, 57,000 years old.

It's black, it's fine-grained lava, but the walls of the Columbia River Gorge, both on the Oregon side and the Washington side are made out of basalt as well.

It looks exactly the same kind of stuff.

But it's 16 million year old lava.

Each lava flow 100 feet thick, and each of those giant lava flows did not erupt here, they erupted inland over by Idaho, and then flowed 300 miles to the Pacific Ocean.

That regional basalt story is way older than the cutting of the Columbia River Gorge and therefore, way, way older than the basalt story here, the Beacon Rock cinder cone volcano.

(upbeat guitar music) Can we please visualize the cinder cone volcano at its maximum size?

Geologists have done that.

Add 200 vertical feet of red cinder to the top and to the sides of Beacon Rock.

Can you do it?

That's the original shape and size of the Beacon Rock cider cone volcano.

But during the Ice Age, during the Ice Age floods, the famous Ice Age floods that came down the Columbia River Gorge, there was so much water moving more than 40 miles an hour that the Ice Age flood water easily overtopped the cider cone volcano and took all the cinders away.

Those red cinders are now piled up downstream of here, and all we're left with is this beautiful majestic monolith made out of black basalt lava, the guts of the original cone.

And that cone is way younger than the Columbia River Gorge itself.

How about that for a geology lesson here in the Columbia River Gorge?

(upbeat guitar music) - [Presenter] This series was made possible in part with the generous support of Pacific Science Center.