During this week, our class traveled to
Svea located in Van Mijenfjord, southeast of Longyearbyen. Svea is a mining
settlement, originally founded in the early 1900s by a Swedish mining company;
in fact the name Svea is the old name for Sweden. The settlement accommodates
people working in the mine or in the nearby facilities; approximately 300
people live there but no one stays permanently. Miners work shifts of 12 hours
a day and live in the settlement since there is no public transportation in and
out of Svea. The workers commute on a company-owned aircraft from Longyearbyen
and stay for few days in Svea and then fly back home to Longyearbyen for a few
days off.
We had two main goals in Svea, the first
one was to look at glacial sediments deposited by Paula Glacier, a glacier that
ends directly in the water of Van Mijenfjord and has experienced glacial surges
since the last glacial maximum, approximately 20,000 years ago. A surge is a
rapid event during which the glacier advances at fast velocities while
“pushing” and depositing sediment at its front and flanks. The second goal was
to study modern Arctic tidal deposits in Braganzavågen, an enclosed bay just
east of Svea and connected to Van Mijenfjord by a short channel. The enclosed
bay formed during the last glacial maximum when Paula glacier was far out into
the fjord and formed an end moraine that blocked the exit of water from rivers
coming into the bay, forming a dam lake. Part of the end moraine is still there but
water can get in and out of Braganzavågen since the glacier has retreated. The
water depth is very shallow, close to 20cm deep, even shallower in some areas,
and here is where tides come into effect since the tidal range is close to 2 m
in this region.
“Welcome to Svea”
sign at airport. Miners use this airport several times a day to
travel to and from Longyearbyen.
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The invited lecturer for the week was
Dr. Eiliv Larsen from the Geological Survey of Norway. He is an expert on
arctic glacial deposits and geomorphology and has studied the Svea region. On
Monday, we only had a short morning lecture on glaciers and their deposits, as
well as a short introduction to the research area. The afternoon was used to
pack for our trip and to get all the necessary equipment from UNIS.
On Tuesday morning we took a short
flight, along with a few miners, to Svea. The flight was about 15 minutes long;
it took more time to load the plane than the time we spent on the air. We
arrived to a very small airport, with only one building and the control tower.
UNIS rents a house that has been modified as dorms and this is where students
and faculty stay when visiting Svea. In the afternoon, we drove around the area
to get familiar with the geology of the region. The most impressive feature was
Slak glacier that drains into Braganzavågen. Interestingly enough, the entry to
the mine is right next to the glacier.
Student gear, sampling devices, shovels,
and riffles to be used in the field.
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The following day we ventured into the glacial deposits right next to Van Mijenfjord. The area is characterized by hummocky structures and the surface sediments have been interpreted as reworked marine sediments. We had an interesting discussion on some glacial deposits that present folding, which is possible because the deposits are very stiff due to the compression of ice. One of the hypotheses for the folding of the structure was ice coming from two different sources and therefore compressing the rigid deposits in two directions.
Students and
professors describing and discussing
beach deposits, Braganzavågen on the background.
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At
the beach, coal fragments that have been carried by currents from the nearby
mine. In the background, hummocky structure of glacial deposits with no
vegetation cover.
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Students
describing intertidal bar deposits. This particular bar has not been covered by
water in a long time since vegetation is currently growing on it while the
surrounding channels are active.
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We spent Thursday all day walking on
mud, which is harder than it sounds, especially if the mud reaches up to your
knees; in Braganzavågen this is the case. We were divided into groups to study the
different aspects of the tidal flat environment; tidal channel, intertidal
bars, and supratidal bars. Relatively few studies on tidal systems in modern
glaciated areas have been completed; surface ice, permafrost, and the minor (if
any) biogenic activity are some of the features that differ from low latitude
regions. The end product of our observations this day was a term paper in which
we all worked over the weekend. Even with the limited time in the field area we
were able to identify key features for tidal flat environments like mud drapes
and sediment fining patterns. There were also a couple of interesting features
in the area; algal mats, that look like wet, wrinkled paper, and superimposed
ripples, these possibly formed by currents at 90° from each other creating a square
net-like configuration on the surface of the intertidal bars.
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