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| Molly Miller in Antarctica |
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On Monday, November 17, Nichole Knepprath and I left McMurdo Station, the main
U.S. base in Antarctica, and flew in a C-130 Hercules plane to the Beardmore
Glacier area in the Transantarctic Mountains. The C-130 is a fat, low-slung
airplane used by the Air National Guard. It is designed to carry cargo efficiently,
so there are few amenities for human passengers. We could barely squeeze into
the webbed seats because the piles of boxes containing our gear – tents, food,
stoves, geology hammers and picks, computers, etc. –
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| Molly Miller investigating rocks
on Mt. Bowers |
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were jammed in so tightly.
The C-130 is equipped with skis, so the landing on the snow at the Beardmore
Camp was smoother than many landings at American airports.
Once at the Beardmore Camp, half of our party set about
putting up tents while the other half took a reconnaissance flight in a small
Twin Otter aircraft to identify an area where we could work effectively for
the next six days. (The same small plane has been used in recent
years to
evacuate people taken ill at the South Pole during the winter.) The
area we chose was Mt. Bowers, located about 100 miles away, where ice of
the Polar Plateau squeezes into the Beardmore Glacier. The pilot was concerned
that the snow was too hard for the plane to land. To test the snow consistency
our pilot flew low, gently touched the snow surface, and quickly took
off. Fortunately, the snow was not hard enough to damage the plane.
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| Molly Miller leaving her Scott
tent at Mt. Bowers. Tents of this design were originally
used by Robert Scott on his failed expedition to
the South Pole in 1912. Many experts feel that the
Scott tent can withstand higher winds than any other
design. |
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Mt. Bowers: The next day the Twin
Otter ferried the six members of the Vanderbilt–University of Wisconsin–Milwaukee
team and our cargo to Mt. Bowers, where we spent the rest of the day
erecting tents. Tents must be attached securely to the snow with strong bamboo
poles and snow must be piled up along the sides to insure that they do not
blow away. At Mt. Bowers the snow was too hard to dig with a shovel so I
put heavy bags full of survival equipment on the flaps at the edge to hold
it down. We stayed at Mt. Bowers six days. We found some interesting things
in the rocks. In addition, the stay was a true introduction to Antarctica
for rookie team members.
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| Two party members, lower left,
examining rocks exposed at Wahl Glacier. Note ice
falls in the distance. |
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Beardmore Camp and Wahl Glacier: We returned to the Beardmore
Camp on November 24 and again set up our tents. Since then we have
been making day trips via snowmobile to Wahl Glacier, where ice cascading
over and between mountains creates spectacular scenery
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| Travel by snowmobile to Wahl Glacier.
The snowmobile is roped to the sled and snowmobile
in front of it, and the person is roped to both. |
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The trip to Wahl
Glacier is more than 26 kilometers (15 miles) of irregular snow and ice.
Traveling is particularly tricky because the snowmobiles, sleds and people
are roped together so drivers must be very careful driving.
The
purpose of the roping is to minimize injury and damage should a snowmobile
break through a snow bridge and fall into a crevasse. Mountaineer Tim
Cully discovered a number of crevasses near the Beardmore Camp. Although
they appear to be covered by strong snow bridges, the precaution is worth
the inconvenience because none of us relishes the thought of falling
into a crevasse, particularly while on a snowmobile.
The weather: Mt. Bowers' position near the Polar Plateau
makes it susceptible to strong katabatic winds. While we were there, the
temperature was -25 degrees Fahrenheit (F) or lower with winds of about
25 mph that created wind chill factors of about -80 degrees F. We noticed
each others' faces getting white from frost bite and made sure that we warmed
those spots. At Beardmore Camp and Wahl Glacier, by contrast, temperatures
have been high (0 to 10 degrees F) and the winds light. It feels almost
balmy!
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| LEFT: Fossilized trails and burrows
made by animals moving in the sediment at the bottom
of a lake approximately 280 million years ago. RIGHT:
Complex ripple marks made by water current moving toward
the top of photo |
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What we have found: In the oldest rocks exposed at
Mt Bowers we were able to use the marks left by animals moving in
the lake sediment to identify both the environment that the animals
preferred and the processes that filled the lake with sediment. Animal
trails and burrows are most abundant in the shales that were deposited
in the quietest water.
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| Trackway produced
by the appendages of an ancient animal
digging into the sediment as it moved
along a stream bottom or nearby floodplain.
Miller found the trackway in a block
of sandstone on Mt. Bowers. |
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The animals preferred the environment with the
least current activity. With time, the currents brought in
more and more sand, recorded in ripple marks that reflect strong current
activity. Eventually the lake filled with sediment from the rivers
that emptied into it.
Our biggest surprise at Mt. Bowers was finding
a fossil trackway made by an animal moving near the margin of an
ancient stream 250 million years ago.
This type of fossil has never
been found in rocks of this age in Antarctica. It is not clear whether
the producing animal was a reptile or whether it was an arthropod.
However, the absence of obvious “toes” makes it more likely that it
was an arthropod similar to a crustacean.
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| LEFT: Vanderbilt geology
graduate student Nichole Knepprat enjoying the fine
weather on the snowmobile trip to Wahl Glacier. RIGHT:
Sequence of rocks containing ancient plants and paleo “soils” that
existed 240 million years ago just before the largest
mass extinction ever recorded that caused the demise
of an estimated 90 percent of marine species. |
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Rocks at the Wahl Glacier show more evidence of
plant life than animal life. The distribution of the plant fossils
within the strata is of particular interest to Nichole Knepprath,
who is doing her master's thesis
research on the Antarctic record of the world
wide disappearance of coal about 240 million years ago. She is documenting
the distribution of plant material in layers exposed at Wahl Glacier
and finding that plants were abundant close to the time that coals
were no longer being formed
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| Miller and colleagues
relaxing over a meal in the cook tent. |
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Starting December 1, two helicopters
will begin operating out of the Beardmore Camp. They will greatly
enhance our ability to get to exposures of different rock units.
Stayed tuned for what we find
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