Methods for a large-scale scientific mission to a subglacial lake in
Antarctica were published earlier this month in the journal Reviews of
Geophysics. These plans, which involve drilling into Lake Ellsworth on
the Antarctic continent to collect a number of microbial and ice core
samples, are believed to constitute a relatively non-destructive
strategy for exploring what is currently unmapped polar terrain.
Researchers with the British Antarctic Survey expect to complete their
mission over the next two years, and an initial four-member exploratory
party has just returned this week after setting up an initial base camp
for the mission.
The lake, which is situated very close to both the Ronne Ice Shelf
and Vinson Massif at the base of the Antarctic Peninsula, lies under
roughly two miles of ice, making the logistics behind this project very
complicated. To succeed in their mission, the researchers hauled 70
tons of equipment overland by tractor-train for three days to arrive at
the lake, and will return to the location in November to begin drilling.
Because of the extremely short “summer” in Antarctica, the team can
only work between November and mid-January, and this season’s window
appears to be drawing to a close.
“This is a major milestone for the programme and we are delighted
that our complex logistical operations were a success this season.
Working within the short Antarctic summer season adds pressure to our
time on the continent, which is why we had to plan two stages of the
programme. The drilling season is nearly upon us, and we still have a
long way to go before we can access Lake Ellsworth, but the success of
the Advance Party this season certainly puts us in a good position for
November,” said Chris Hill, one of the group’s advance team members and
program managers.
“Lake Ellsworth is extremely remote, cold and hostile — ambient
temperatures dropped to −35°C and with wind chill they dropped further
still making living and working on site a physical challenge. We
deliberately located the equipment over a kilometer (1.7km) from the
drill site to protect it during the harsh Antarctic winter. We will move
it to its final position and set up the rig ready for drilling in
December,” said Andy Tait, one of the team’s engineers.
Several features make Lake Ellsworth more appealing for this type of
study than other subglacial lakes which have been discovered. Of the
386 lakes that have been previously mapped, the proximity of Ellsworth
to the nearest research station certainly constituted one of these
factors, as did the sheer size of the lake. Using radio echo sounding
techniques in 2010, the team has measured the lake to be 14 kilometers
long, 3 kilometers wide, and 160 meters deep. Typically, lakes of this
size are created when the bottom layer of a glacier starts to melt as a
result of geothermal heating; the melt water then pools in areas where
the underlying topography forms troughs or valleys, resulting in a lake
underneath a massive glacier or icefield.
continue>>>>
continue>>>>
No comments:
Post a Comment