How the Earth Was Made

>> Earth. A 4.5-billion-year-old

planet, still evolving. As

continents shift and clash,

volcanoes erupt, and glaciers

grow and recede, the Earth's

crust is carved in countless,

fascinating ways, leaving a

trail of geological mysteries

behind.

In this episode, Europe's

greatest mountain chain, the

Alps, is explored. Home to some

of Europe's highest peaks,

longest glaciers and sheerest

rock faces, the Alps are one of

the most dynamic and dangerous

mountain ranges on the planet.

A mysterious land where whole

mountains collapse in on

themselves, and where its rock

once lay entombed at the bottom

of the sea. Scientists have been

hunting for clues hidden inside

the rocks, deep within the ice,

and upon some of the most famous

summits in the world to

understand how the Alps formed

and continue to evolve.

Clues which also provide a

window into the formation of

the Earth itself.

S01x13 The Alps Original Air Date on May 12, 2009

== sync, corrected by elderman ==

With more than 100 peaks rising

higher than 12,000 feet, the

majestic Alps tower over Europe.

The mountains are a huge

physical barrier. 750 miles

long, 125 miles wide, and

spanning seven countries,

the Alps divide Northern and

Southern Europe. Home of the

iconic Matterhorn and Western

Europe's tallest mountain, Mont

Blanc, the Alps are one of the

world's highest mountain ranges.

But the majority of these peaks

formed only 30 million years

ago, making it one of the

youngest mountain ranges on

Earth. And for centuries,

geologists have red over these

fabulous rock formations to

figure out how mountains are

made.

But the first person to uncover

a crucial clue to the Alps'

formation was, surprisingly, a

16th-century Renaissance man,

Leonardo da Vinci. He was not

only a great artist, he also had

a brilliant scientific mind.

Da Vinci was a natural detective

who saw the world around him as

a huge mystery waiting to be

solved.

He focused his inquisitive,

scientific mind on the Alps at

a time when most scholars

believed the Earth was flat.

Da Vinci had heard tales of an

extraordinary discovery

embedded in the rocks, and in

1510, he trekked high into the

mountains to take a look.

At 7,000 feet, he found what

he'd been looking for.

Fossils. He knew these creatures

came from the sea, that they

could not have lived in the

Alps. So how did they get there,

more than 100 miles from the

nearest ocean and thousands of

feet above sea level?

The 16th-century explanation

provided by the powerful

Catholic Church decreed that the

marine fossils must have been

washed up during the time of

Noah in 2300 BC.

The holy scriptures describe how

God, sickened by the wickedness

of mankind, inflicted a

terrifying deluge of water upon

the Earth. All forms of life

were annihilated, except those

sheltering on Noah's Ark.

The great torrent of water that

flooded the Earth must have

washed some of the sea

creatures 100 miles inland.

But da Vinci did not believe

this explanation and continued

his investigation as to how the

fossils got there.

In the Säntis Mountains,

northern Switzerland, 500 years

later and 7,000 feet above sea

level, it's still possible to

see the fossilized remains of

sea creatures that so intrigued

da Vinci.

>> Here we have a rock which is

almost covered with fossils,

for example, here, a

cross-section of a clam.

Here below, we have the skeleton

of a coral.

>> Poring over the fossils, da

Vinci carried out an ingenious

piece of detective work. He

found the fossilized remains of

two-shelled creatures that

amazingly still had both halves

intact. If the Church's

explanation of a cataclysmic

flood were true, then the

torrent of water would have torn

these delicate creatures apart.

Da Vinci proposed that these

fossils had formed under the

ocean, and that some other force

had brought them high into the

mountains.

Modern-day scientists have

identified the species

fossilized in these rocks, and

can accurately pinpoint when

they lived.

>> The fossils we see here

actually lived 100 million

years ago in a warm, tropical

sea.

>> This ancient, tropical sea

teemed with life and rich coral

reefs. The sea floor was covered

in urchins, clams and other

species, many now extinct.

Just as da Vinci had imagined,

when some of these creatures

died, they were preserved

intact. Their shells then became

buried in the sediments at the

bottom of the sea and preserved

as fossils when the sediment

turned to rock. But what could

these fossils reveal about the

formation of the Alps?

Again, it was da Vinci's

exceptional powers of

observation that helped unravel

the mystery. He noticed that the

spectacular fossil-bearing rock,

known as limestone, was laid

down in layers several thousand

feet deep. 400 years later, it

was discovered that, along with

the fossils, hidden in the

microscopic structure of

limestone is an essential clue

to solving the mystery of how

the Alps formed--remains of

trillions upon trillions of

seashells. Limestone forms as

tiny sea creatures sink to the

bottom of the ocean. Piling on

top of one another, they compact

together under their vast

accumulated weight, forming

layer upon layer of sedimentary

rock. The Säntis Mountains, like

large areas of the Alps, are

made almost entirely of the

shells of dead sea creatures.

Beds of limestone here are

several thousand feet high--

evidence of the extraordinary

amount of sediment that was

laid down on the ancient sea

floor.

>> We have here a massive

package of limestone, layer

above layer of sea floor, and

this was brought up in an

upright position during the

building of the Alpine mountain

chain.

>> Ancient clues reveal the

origin of the Alps.

Marine fossils are evidence that