Welcome to Vancouver Island, British Columbia, Canada.

That's Nanaimo right over my shoulder.

And this is Wrangellia.

We're paying our respects to the OG, the original exotic terrain that showed up in the scientific literature more than 50 years ago.

There's three distinct stories coming from the bedrock of Vancouver Island.

And more interesting than the bedrock sometimes is where the rock is missing.

There's more than 200 million years of missing time right here.

What's the story with that?

We start our geologic story with the bedrock of Vancouver Island, with the Karmutsen basalt.

Two thirds of this island is this basalt.

It's 230 million years old.

That's way, way older than the Columbia River basalt, which is 16 million years.

So this Karmutsen stuff is way older and it's way more voluminous.

The pile of Karmutsen basalt is more than four miles thick compared to the Columbia River basalts.

And it's got a longer history out in the Pacific Ocean.

That's another big difference.

How do we know we were out in the Pacific?

Look at the size of these pillows.

This is pillow basalt.

And the pillows tell us that we had eruptions under the ocean.

We had orange, runny lava getting themselves to the base of the sea.

And these lavas are crackling their way up into the water and forming these shells.

This is from the age of the dinosaurs and we still have these original forms of these lavas that were erupting.

That's pretty wild.

But was there an older history of Vancouver Island?

Is it possible that these flood basalts erupted onto even older rock that was already out in the Pacific Ocean?

So if the basalts make up two thirds of the island, it's pretty rare to get a chance to see what's underneath the basalts.

This is a look.

These rocks are 300, even 400 million years old, and they are very difficult to break open.

Can you hear that?

It's mud turned to stone, but then baked a few times, and you can maybe see that there's these pages in a book essentially.

These are the layers of mud that have been turned on their sides.

And we're going back 400 million years with this mud that formed out in the Pacific Ocean, tied to an oceanic island arc long before the basalts.

Think the Aleutian Islands off the coast of Alaska today.

A whole line of these erupting volcanoes where we have a subducting oceanic plate.

These muds are tied to that story.

So we have this as chapter one.

The basalts are chapter two.

Is there a chapter three?

Are there younger than the basalt layers here on the island?

There are.

And they're right over there.

There is an ending to our story, the youngest of our three major And this is what it looks like.

This is the Nanaimo group.

A collection of sedimentary deposits, river cobbles and sand.

The cobbles and the sand are glued in here, this is 80 million years old.

I can't take this stuff out.

But the round nature of these cobbles tells us we had North American, that's right, North American rivers decorating the top of the earlier two chapters, that was a Pacific story, correct?

So we're done with the Pacific stuff by the time we get to 80 million years ago, because the exotic terrane, Wrangellia, has been accreted, it's been added to the edge of North America.

Very good.

So Sicker Group, the oldest oceanic island arc, Karmutsen basalt, the middle chapter, and now the Nanaimo sandstone and conglomerate.

So where is this big gap I talked about at the beginning of the episode?

So even if you knew nothing about geology, maybe you would notice this face on Vancouver Island and wonder if there's a story.

Because below this boundary, everything's at sharp right angles.

And this is the Sicker 300 plus million year old material.

And then you'll notice that everything above is not that.

It's a bunch of river cobbles, sands and other blocks.

That's the Nanaimo, 80 million years ago.

What's missing here?

What we started the episode with.

Where is the Karmutsen basalt.

I thought it was four miles thick, covering most of the island of Vancouver Island.

It's not here.

It was likely here at least a couple miles of the basalt.

But it's gone.

And unconformity is a gap in the rock record representing missing time.

I'm putting my finger on a boundary that represents more than 200 million years of time, and there's no rock to show it.

There's no rock record to represent that amount of time.

That's crazy.

So there's mystery here.

The basalt was here.

It's no longer here.

It had to be stripped out of here before the Nanaimo was deposited.

Why?

We don't know.

The research continues here on Vancouver Island.