00:00 Ariel
view of Antarctic coast
As
above, closer to the ground
As
above
Guide Voice: The Antarctic – one of the
most inhospitable regions on the planet; not the first place that
most people would think of as a location to study volcanic activity
– but that’s exactly where scientists from the
UK’s Durham University went, as part of an international
expedition under the auspices of the Johns Hopkins University, in
an attempt to unravel some of the more complex problems associated
with volcanic activity.
00:24 SOT: Jon Davidson, Chair of Earth Sciences,
University of Durham – “One of the
objectives of the research is to try to understand what happens
underneath volcanic systems, to understand what the plumbing system
is doing, what the timescales are over which it is operating,
what’s actually happening down there and ultimately how that
might be related to what happens at the surface like eruptions
which have implications for all of us”.
00:45 Ariel
view - snow on mountain peaks, Antarctic
Pan
across Dry Valley floor
Guide Voice: But why go to Antarctica? The
answer lies in one of the strangest areas of this strange
landscape.
00:53 SOT: Dr. Dougal Jerram, Total
Lecturer, Department of Earth Sciences, University of
Durham – “It’s certainly one of the
geological wonders of the world, the locality known as the dry
valleys in Antarctica. It’s basically where the
trans-Antarctic mountains, between the trans-Antarctic mountains
and the coast, they essentially block off the ice shelf from
advancing any further. That combined with the fact that the area
doesn’t have much precipitation at all, it’s
effectively a desert, means that any ice material starts to
sublimate and that means it’s essentially turning to gas and
evaporating away.’’
01:26 Helicopter
landing in Dry Valley
Wide,
scientists in Antarctic Dry Valley
Wide,
JD & DJ at High Force Waterfall
Guide Voice: It’s here, in this bizarre
landscape, that scientists are able to gain access to volcanic rock
in a way that isn’t possible anywhere else on earth.
01:35 SOT: Jon Davidson (with Dougal
Jerram standing at High Force Waterfall in Teesdale, Northern
England) – "This is High Force in Teesdale
and the reason High Force is here is because there is a sill that
forms a resistant rock behind the waterfall, and the sill is part
of the Whin Sill which is forming the top part of the waterfall and
towards the bottom of the waterfall you can see there’s some
layers which are sedimentary rocks into which the sill has been
intruded horizontally."
01:58 Pan
across Dry Valley (from helicopter)
Scientific
expedition on valley floor
Scientists
examining rock sill
Durham
scientists viewing crystal on 3D screen
Reverse
of above
c.u.
projection of crystal
c.u
researcher preparing samples for analysis
c.u.
hands handling samples as above
Guide Voice: Working in the Dry Valleys of
Antarctica these volcanic sills are completely exposed.
There’s no vegetation or layers of sedimentary rock to impede
access to the outcrops, giving the scientists the opportunity for
close study that doesn’t exist in other locations - they can
more easily access what they refer to as the plumbing system that
transports magma to the earth’s crust.
Their research uses new techniques from a range of disciplines,
such as this three-dimensional imaging in Durham University’s
E-Science Research Laboratory, to look at the textures formed by
crystals contained in volcanic rock. By analysing these crystals
the researchers hope to be able to put more accurate time scales to
a range of volcanic activity.
02:41 SOT: Jon Davidson -
“One of the ways I’ve often thought of these
crystals is in the same way as you study tree rings, you look at
the cores of the crystals and the progressive growth rings of the
crystals and they give you a record through time as to what
the magma was like as the crystal grew. So its very similar to the
record you get from a tree ring, you’re looking at the
history of the evolution of magma, by looking at the various growth
rings on these crystals”.
03:03 Researcher
at laboratory desk
Pan
– magazine of crystal samples being placed in
spectroscope
c.u.
of above
Wide,
researcher at spectroscope
JD
calls researcher to computer terminal
Over
shoulder shot of computer screen
Hand
on computer mouse
Pan
from JD to researcher
c.u.
data on computer screen
Zoom
in from wide of volcanic activity, Montserrat, 1996 (archive)
Guide Voice: Recent technological advances mean
the scientists can analyse single crystals or even make several
analyses of a single crystal. Isotopic compositions act as a sort
of rock DNA to tell what the origins of the crystal or parts of the
crystal are By analysing isotopic compositions from core-to-rim
they can recover a history of the changing environment in which the
crystal grew.
It’s their hope that this information will help them to
better understand the cycles of volcanic activity as these can have
significant effects for human society, not least in their impact on
climate change. It’s this volcanic impact on climate that has
been linked with some of the major extinctions of species that
we’ve seen in the past.
03:45 SOT: Jon Davidson –
“Now the sorts of eruption that would have been
associated with the magma systems we were looking at in Antarctica,
are actually different from even the super volcanoes, they would
tend not to have been very big explosive eruptions, but very big
eruptions over large areas from which the main product would have
been lava, very, very, very extensive flows of lava, bigger than
we’ve ever seen historically erupted. Associated with that
though is a lot of emission of gases like sulphur dioxide, and
it’s really sulphur dioxide that’s one of the problems
in climate change”.
04:18 Plumes
of gas rising from slopes of volcano (Montserrat archive)
As
above
Wide
ariel view across Antarctic Dry Valley
Guide Voice: Can we expect another period of
major volcanic activity? No one really knows, but perhaps the
secrets locked in Antarctica’s frozen deserts will help these
scientists to prepare for just such a possibility.
04:31 End
of cut
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