A great expanse of ice
by Guest Blogger
August 1, 2005
Today I had an interesting experience. I accompanied a scientist up onto
the ice sheet to drill for ice core samples. I’ll make the distinction
between glaciers and ice sheets by saying 82% (at least) of Greenland is
covered by a massively thick layer of ice. At its centre it’s 3
kilometres (1.9 miles) thick. That’s the ice sheet.
When the ice sheet
gets close to the coast, it squeases out between the coastal mountains.
What is squishing out between the mountains are glaciers. So a glacier,
big as it is, pales in comparison to the immensity of the ice sheet.
We were on the ice sheet on the east coast of Greenland. Just a big
sea of featureless ice white landscape, stretching away all the way to
the west coast hundreds of miles away. It was blindingly white. The
helicopter pilot complained that the landscape was so featureless that
he had a hard time landing, as it was hard to tell how far above the ice
he was. There was no reference point. Just a smooth white surface as far
as the eye could see.
The ice coring machine was driven by a small two stroke engine and
consisted of a hollow tube which was called the auger and pipes which were
added above it as it’s depth increased. The auger was 1.5 metres (5 feet)
long and cut a cylinder of ice about 10 cm wide x 1.5 metres (4 inches
x 5 feet) long. Sections of pipe were added above the auger as it went
As it went deeper it became heavier and more difficult to
retrieve. Once we drilled down a further 1.5 metres we stoped and pulled
everything out of the hole to retrieve the bottom auger section.
auger section contained the core sample. We carefully pushed the sample out
of the auger. Then we measured it, weighed it, photographed it, sectioned it
into 20 cm lengths, quarterede the sections, then recorded and bagged the
quartered section. There were usually 5 to 6 sections per core sample.
Then we would reassembled the auger and drilling pipe, adding another
metre of drill pipe and started the process again.
We woke up at 05:00 a.m., got to the ice sheet at 05:30, and got back to the
ship at 13:00 p.m. We worked steadily during our time on the ice and
managed to drill to a depth of 11 metres. According to Jason Box (Ohio
State Geography/Byrd Polar Research Center), the scientist for the ice
sampling, we ended by drilling ice from the summer of 2003. Eleven
metres of compressed snow and ice in two years!
I’m impressed. But then again everything thing about Greenland leaves an
impression on me.
peace and love,