The Day the Dinosaurs Died Page #5

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'far away from the impact zone itself.'

Protected by the water, marine

creatures like the mosasaurs

may have been able to survive

these immediate events.

But for the dinosaurs on

land, with nowhere to hide,

this was the beginning of the end.

To show how the effects

might have played out

for dinosaurs on the ground,

we've enlisted palaeontologists

Steve Brusatte and Tom Williamson

to our international team.

They've come to New Mexico,

1,200 miles from the impact zone,

hunting for remains in one of the

richest dinosaur fossil sites

in the world.

- Yeah. OK.

- Whoa.

- Got a bone layer.

- Look at this. Check this out.

A lot of times, we'll just be

walking around in the Badlands,

looking for stuff that's

sticking out of the rock.

That's always the first clue.

This one's really sticking out.

We can tell from the shape of it

that it's part of the

backbone of a dinosaur.

It's a bone from the backbone

of a horned dinosaur.

This is probably Pentaceratops,

which means five-horned face,

two brow horns, a nasal horn and

then a cheek horn on each side.

Triceratops has three horns on its face.

This guy had two more

horns, so five horns total,

so an even gaudier dinosaur.

The ceratopsians, like

Pentaceratops and Triceratops,

were a large group of

plant-eating dinosaurs

that roamed the American landscape

for the 20 million years leading

up to the asteroid impact.

- There it is.

- Pretty good. Look at that. - Not bad.

This whole area here,

honestly, it's littered

with these kind of bones.

These were the cows of the Cretaceous,

they would've been everywhere

on this landscape.

66 million years ago, this area

would've looked very different.

Today, it's known as the San Juan Badlands.

Back then, it wasn't so bad at all.

This whole area was a lush jungle.

Dense vegetation.

Thick forests cut through

by flowing rivers.

When that day started, this whole

area here would've been teeming

with dinosaurs, and then,

about 2,000km or so,

1,200 miles in this direction to

the south-east, the asteroid hit.

And very quickly, the

dinosaurs would've realised

that something was wrong,

because there would've been

an enormous red glowing cloud

that would've filled up

much of the sky here.

The glowing cloud would've looked dramatic,

but this far from the impact zone,

the dinosaurs here would've

been safe... for now.

Now, their cousins down in Texas,

about 1,000 kilometers

closer to the impact site,

they were toast.

They were incinerated, they were vaporized.

By studying the Yucatan rock core,

we know the exact timing

of what happened next.

11 minutes after the impact,

the vapor cloud arrived in New Mexico.

The skies darkened and the

temperature started to rise.

It wasn't really a case

of fire and brimstone

raining down from the heavens.

It was more a case of all of that

stuff heating up the atmosphere

and turning the atmosphere

into a giant radiator.

The heat was so intense that,

over 1,000 miles away from the impact,

many animals would have been roasted alive.

Climate specialist Dr Brian Toon

is the first scientist ever to

theories what happened next.

A devastating global firestorm he's

studied for more than 20 years.

It wasn't falling on you, it was

60km above the ground or so,

and the glowing hot lava was

emitting an amount of energy

that's a few times larger than the sun.

This is not a normal fire.

The fire was started everywhere,

which causes what's called

a mass fire.

Mass fires can be much

hotter than a normal fire.

Well, the leaves on the ground caught fire,

leaves in the trees caught fire...

The underbrush caught fire.

There's winds at hurricane

speeds rushing into the fire,

drawing upward into the rising flames

and they consume everything.

And this vapor quickly

spread across the planet.

Probably only took a few hours

for it to reach the furthest

reaches of the Earth.

Thanks to our new model of what

happened after the impact,

we now know that fires spread

right around the globe.

But were these fires devastating

enough to cause the extinction

of all of the world's

dinosaurs in a single day?

'To find out, I'm traveling

far from the impact site

'to the very tip of South America

'and the remote wilderness of Patagonia.'

Over 4,000 miles away from

where the asteroid hit.

I am all the way down here in Chile.

Now, we tend to think of this asteroid

as being absolutely enormous,

and it was - 14km in diameter -

but in the context of

the size of the Earth,

that's like a grain of sand

impacting on a bowling ball.

And I want to understand

what kind of impact

the asteroid landing here

had on the dinosaurs

right down here at the

toe of South America.

Leading the hunt for clues is

palaeontologist Marcelo Leppe.

He's taking me to look for dinosaur remains

in a mountain valley that's

best accessed on four legs.

Marcelo, can you explain to me how

the geology of this valley works?

Actually, we are passing through time

and we are moving to the

end of the Cretaceous,

to the end of the age of the dinosaurs.

We are, at the moment,

in 80 million years ago,

this is Campanian.

So this is fantastic.

As we ride along the

valley, as we ride north,

we're riding from 80 million

to 66 million years.

Through time.

Getting closer to that extinction event.

We've reached the Valley of the Dinosaurs.

Now I want to see what sort of

dinosaurs lived here and find out

what happened to them in the

hours after the impact.

So, shall we get off and have a look?

- Yeah, let's leave the horses and look.

- Seems like a good idea.

The place is literally full of bones.

As you can see, this sunlight is the best

because the angular light

is reflecting the bones.

- Let's see if we can find a dinosaur,

then. - Yeah, let's... let's see.

Oh, for example, there.

Or here.

Look, just beside you.

- This, here?

- Yes, this is a dinosaur bone.

Oh. That's fantastic.

They're different color.

Greyish, or white.

Yeah, so what's that, then?

Oh, it looks like a vertebrae.

Probably the first one.

OK, so... yeah.

That looks like a facet, it looks

like the surface of a joint

and that would be where the skull sits.

Any ideas what species?

- Yeah, probably a hadrosaur. 99%.

- Really? - Yeah.

- That's your first hadrosaur, yeah?

- Yeah, it is.

'This valley is now a bone

bed, four miles long.'

Yes, that is a bit of fossilized

bone and they're everywhere.

Scattered across this hillside.

It's just extraordinary.

Once, it was home to herds of hadrosaurs.

Plant-eaters up to 30-feet long with

a distinctive duck-billed face.

But did the dinosaurs down in Patagonia

die on the day the asteroid hit?

Thanks to the team in Bremen,

we now know that once the asteroid

struck the Yucatan Peninsula

over 4,000 miles away,

it took 42 minutes for the

superheated cloud of debris

to reach Patagonia.

For much of the planet,

the fires triggered by the burning sky

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