- What does it mean to be curious?

For my students, curiosity creates opportunities for a bigger and brighter future.

(gentle music) - Anacortes, Washington, the gateway to the San Juan Islands here in Western Washington.

It's a beautiful spot and there's bedrock everywhere.

And the bedrock is incredibly old.

160 million year old bedrock from the age of the dinosaurs.

That's one reason to come here, but another reason to come here on Fidalgo Island is that there's a very young story.

15,000 years ago, everything got sculpted, beveled, fluted, streamed over.

What happened here 15,000 years ago to do that?

(gentle music) So driving to Anacortes does feel like you're driving on the mainland, but this is Fidalgo Island, part of the San Juan Islands.

Here in the Pacific Northwest, every island has a complicated set of bedrock that's right at the surface.

There's no cover.

And so this very old bedrock is generally brown, kind of junky looking rock.

But the true color of the rock is green.

It's peridotite from the upper mantle, 160 million years old.

And the kicker is this is not peridotite that came up here in North America.

It came up in the middle of the Pacific Ocean.

It's part of the old sea floor.

And a hundred million years ago, that old ocean basement was added to North America.

Plastered on.

It's here now forming the foundation of our story.

(gentle music) Well, yeah, that's the bedrock, the draw here in Anacortes.

But there is glacial till directly on top of the bedrock.

It's pretty wild.

This tan deposit with these individual stones, sand surrounding these pebbles, this is a classic look of glacial till and any glaciers around the world, deposit stuff that looks exactly like this.

These are Canadian rocks and Canadian sand that came across the border 15,000 years ago, not even one million years ago, including this incredible boulder, a glacial erratic.

This is a boulder of granite.

It's sitting right on top of green peridotite.

This had to be moved in and it was by the thick Canadian ice sheet 15,000 years ago.

So the erratic, the till, they're young, the bedrock is old.

And so what's in between?

What am I standing on?

An unconformity, which is a gap in the rock record that represents missing time.

How much missing time is here, I don't know.

You do the math for me.

160 million minus 15,000.

That's a lot of time that's gone here on Fidalgo Island.

(gentle music) Well, this place has it all.

It's got the peridotite, it's got glacial till it's got an erratic, but now we have striations on this surface.

So to set you up to enjoy these glacial striations, I can pull a rock right out of the till.

And this rock and many others have been dragged by the ice sheet over this surface.

And these rocks in the till have left these striations.

These perfectly linear and parallel striations, scratches that record perfectly the direction of the Canadian ice sheet flowing over this portion of the San Juan Islands.

It's not the ice that's leaving the scratches, it's the stones that are being carried by the ice.

This is the level of preservation we normally don't get a chance to see because the till was covering the surface and preserving these delicate scratches.

And it's only recently, maybe in the last decade that this till has been eroded back to reveal these very precise fingerprints of an ice sheet long ago.

(gentle music) So even though we're deep in the woods, we've got the same elements present.

The old bedrock from the middle of the Pacific Ocean, the beautiful glacial striations on a sculpted surface.

But what's the difference?

The difference is this is an almost vertical wall, and I don't understand it.

Is the ice creating this grooving?

I mean, the glacial striations definitely tell us that.

But the scale of the sculpting, I personally wonder how much water is present at the base of a thick glacier.

The ice sheet is more than a mile thick right here.

In the dark is the water surging through here to help create this vertical wall.

This isn't a lava tube.

This isn't the edge of a petrified log.

This is a glacially sculpted and delicately etched wall deep in the woods of Anacortes.

Plenty of open questions but our old and our young story here in Anacortes, beautifully on display.

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