:12:04
Beneath us, the American plate
and the Eurasian plate are born
:12:08
and slowly grow apart
:12:11
lceland grows
from the center outward
:12:14
at the rate at which
the Atlantic widens-
:12:17
slower than
a human fingernail grows.
:12:21
Yet in 1 80 million years.
:12:24
this slow spreading of
the plates created the Atlantic
:12:29
and in the last 1 3 million years
:12:32
it built
this great volcanic island
:12:34
straddling this boundary
of creation.
:12:45
Far from lceland
and the mid-Atlantic ridge
:12:48
the rifting process
:12:49
which splits continents
and creates oceans
:12:52
has only begun.
:12:55
Yet is has created
a geologic feature so enormous
:12:58
it can be seen from the moon-
the Breat Rift Valley of Africa.
:13:05
This great crack
in the Earth's crust
:13:07
extends for 4,000 miles,
from Mozambique in the south
:13:12
to Lebanon in the north.
:13:15
Where the continent fractured
some 20 million years ago
:13:18
an escarpment plunges 2,000 feet
to the sunken rift floor.
:13:25
The remains of great volcanoes
dominate the Rift Valley
:13:29
eroding monuments to
the continent-splitting forces
:13:33
still at work beneath.
:13:38
On the floor of the Rift Valley
:13:40
roam remnats of the great
animal herds of Africa.
:13:44
They run where valley floor
did not yet exist
:13:47
ten million years ago...
:13:49
where a sea may exist
in ten million more...
:13:52
or a great ocean
in a hundred million.