Friday, December 26, 2008

Beacon Valley

The last stop of our field season is Beacon Valley which is an E-W striking Valley of 900 to 1200 m elevation. In the east it is bounded by the Taylor Glacier, in the west it is constraint by mountain ridges (e.g. Mount Feather) which hold back the ice flows from the Antarctic Ice Sheet. Beacon Valley has two different types of ice. In its upper part buried glacial ice is overlain by a thin layer of sublimation till and soil. Further down towards the Taylor Glacier ice cement is the common type of ground ice. Debris covered glacier originating from nive's in Mullen and Friedman Valley flowing into Beacon Valley. The picture above shows a view from the helicopter above Mount Feather into Beacon Valley; it shows the flow of debris covered glacier from side valleys into Beacon Valleys and Taylor Glacier in the east. In Beacon Valley we have two camp sites one at the Taylor Glacier and one about 6 km further up Valley. The Taylor Glacier (below) creates a 20 m ice cliff and provides us with ice for melting drinking water.

In Beacon Valley surfaces are older than in Victoria Valley and rocks which have been scoured by wind for thousands of years form ventifacts (see below).

The wind also removes the fine sand from the surface leaving behing wind scoured smaller rocks which form desert pavement as shown in the picture below. This desert pavement protects the soil before further wind erosion.

Saturday, December 20, 2008

Victoria Valley

From Taylor Valley we moved to Victoria Valley which is further north at an elevation of 400m. Victoria Valley has two glacier at either end and there is evidence that it was covered by a very large lake about 10,000 years ago. We also have a climate station here and we will drill in the permafrost to investigate the nature of the ice in the ground.
It is much dryer in Victoria Valley than in Taylor Valley. Snow only occurs occasionally in polygon cracks and depressions. The polygonal pattern ground in Victoria Valley is very impressive. Some of the polygon shoulders are 1 to 1.5 m high.

In addition to taking long cores we also use a small rock drill to take samples from the upper 15 to 20 cm of the groundice. The picture below shows Ron and David opening a pit at the shoulder of a polygon from which they retrieve a small ground ice core (see second picture below). The ground ice here occurs in two different forms: as ice cemented sand and pure ice (light part). Ice cemented sand has only small fraction of ice and consits mostly of sand while the pure ice contains only little or no sediment.

The last days we have strong katabatic winds which generate on the Antarctic Ice Sheet. They warm up due to increasing atmospheric pressure from the Ice Sheet (3000 m elevation) to the valley at 400 elevation; temperature increases can be 10 to 20 degrees. The lenticular cloud in the picture below indicats the winds.

Thursday, November 20, 2008

More from Taylor Valley

Last year we installed an automated station that measures wind speed and direction, air temperature, incoming radiation and relative humidity. We also installed temperature probes and moisture probes in the soil. The probes are all connected to a data logger which takes a reading every hour and saves it to a storage module. This year we can download the data and see how temperature and water content changed in the air and the soil. Using these data we want to find out if water is accumulating in the soil or if the soil is loosing water.

This year we are drilling permafrost cores. We will analyze these cores to look at the history of the ice. Some of the ice may be as old as ten thousand years. Analyzing this ice may give us an idea about the climate and environmental situation at this time. In addition it may give us a clue if meltwater from snow is infiltrating into the ground. We use the stable isotope signature of water molecules in the ice to identify climate conditions when the ice formed and other processes like evaporation that affected the ice in his historic or modern time. The pictre below shows a setup of the drill with the tent that blocks the wind and the drill mast sticking out at the top. The tent is important since wind chill temperatures here are about -30 to -40°C (-30 to -40°F). While two drillers are working in the tent to take the core, Ron and Tom are describing the core in detail outside the tent. After description the core is packed and stored at -20 C temperature. It will be shipped back to the laboratory at the University of Washington, Seattle.

Working all day outside in this cold environment consumes a lot of energy. A good breakfast like butter-fried bagels with jam, peanut butter, or Nutella is a good start for the day.

At the end of our stay in Taylor Valley we visited a research group that works in the ocean at New Harbor. Below is a picture from a pressure ridge near the coast at New Harbor and the diving hole (behing Ron). Diving in this water is very cold, the water temperature is -2 C (28.4 F).

Saturday, November 15, 2008

The Research Project

The Dry Valleys are a cold desert. Water in its liquid and frozen form is very rare. Streams only occur as glacial melt water streams. A few lakes exist at low elevation of the Dry Valleys but at higher elevations they disappear. The entire Dry Valleys are underlain by permafrost. Permafrost is ground that has temperatures below 0° C for the entire year. This frozen ground is often a mixture of sediment and ice and is called ice cemented permafrost. During winter when soil temperature drop below -40 to -60°C this ice shrinks and cracks form on the surface. Such cracks are arranged in polygonal pattern. Below is a picture that shows such pattern, the polygons have a diameter of about 20 to 30 m.
Such patterns only form because ice is present in the ground that contracts at cold temperatures. Therefore, everywhere were we are observing polygons at the surface we know that ground ice is present at depth. Our research is tight connected to the ground ice. Since very little snow falls during the year and relative humidity often drops below 10%, it is very surprising that ice is stable in the ground. We want to understand why ice is pervasive in the Dry Valleys (we know this because we can see the polygons at the surface when we fly with the Helicopter). Understanding the nature of ground ice has multiple applications. One is its relation to Mars. Researcher observed the same polygonal pattern on Mars and they know from the Dry Valleys that this indicates ground ice. Understanding the nature of ice in the Dry Valleys will also help understanding if there is ice on Mars and how it may be formed. Actually the Dry Valleys are a lot like Mars (or vise versa) and are called the best Mars analogue on Earth. Secondly, if ice is present it may indicate that liquid water is present which is essential for life. Liquid water could be one mechanism to fill the ground with ice. If we understand this mechanism in Antarctica we may also be able to better understand and prdict the occurrence and persistence of water/ice on Mars.
So here we are and start our investigation. During this field season we will take 10-20 m log cores out of the polygon. The cores will be shipped back home and analyzed for their composition. We hope this will tell us something about the history of the ice.

Thursday, November 13, 2008

First stop: Taylor Valley

At November 11th we arrived at our first location in the Dry Valleys. We flew in with a two 12 Helicopter and it took two trips, one with a sling load to get all of our equipment out.
Our destination is Taylor Valley where we stay close to the coast at New Harbor. We set up the tents and get settled in. Now we are finally ready to start with our research.

Friday, November 7, 2008


Today we are pulling our food. The food that is available for field camps is displayed on shelfs. Here we have to select the kind and quantity of food we want to eat for the next 5 weeks. This is not so easy, since it has to be enough for everybody and should also b easy to prepare on a two-flame gas stove. So we made a list of food we want. Now we have 2.5 hours to collect the items, to pack them in wooden boxes (called rock boxes), weigh the boxes and get them ready for the transport with the helicopter.

After the food pull we go in our cage where personnel from the Berg Field Center (BFC) stored our camping equipment. The BFC is the place were all camping/outdoor gear is stored and maintained. After returning from the field camp the equipment is checked and repaired if necessary. Then it is ready for the next field party.

Our field equipment includes kitchen box, stoves, tents, sleeping bags, waste buckets, shovels, and more. Everything has to be packed into boxes and duffel bags, inventoried and weighted. All equipment goes to the helicopter port ready to be loaded when we fly out. It is important to have the weight of the gear since there is a limit on how much a helicopter can transport.

Wednesday, November 5, 2008

Snow School

Tom and David attended snow school, a two day, overnight campout course to learn and practice camping, survival, and other skills necessary to live and work in conditions of Antarctica. The class begins with a couple hours of classroom learning before catching a shuttle vehicle out to a spot on the ice shelf, where the real fun begins. The day is spent setting up different types of tents, building various snow shelters, and constructing a camp suitable for spending the night. It's all hard work in cold temperatures, so the campers must remember to keep eating and drinking throughout the day in order to maintain warmth and energy. Water is obtained by melting snow over a camp stove.
After spending the night in either a tent or a snow shelter, the campers spend the second day learning how to operate the radios used for communication in Antarctica. With the high frequency (HF) radio, they were able to contact the South Pole station!Over the next couple days we will continue to get our equipment and food ready to fly out to our field camp.