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Yesterday after work I took a walk out to Hut Point, which lies to the west of McMurdo Station. The point is named for the presence of Discovery Hut, built by Robert Falcon Scott for his Discovery Expedition of 1901 to 1904. It was built to serve as a land base for sledging treks on Ross Island and onto the ice shelf. Ernest Shackleton and three companions used the hut in 1909. The hut later served as a supply depot for Scott’s ill-fated trek to the South Pole (Terra Nova Expedition) in 1911-1912, when he and his companions died on their way back to base after reaching the South Pole. They were within 11 miles of a food depot that would have saved their lives, which illustrates Antarctica’s harsh climate. I was unable to go inside (one needs to be accompanied by a guide), but I understand that it is just as it was left almost 100 years ago.
The Discovery Hut was prefabricated in Australia and brought in by ship. Insulation was provided by felt placed between the inner and outer wood plank walls. Apparently, this was insufficient, and the expeditioners preferred to live aboard their ship, which was ice-bound nearby. The hut was heated using seal blubber, which stained the interior walls, the contents of the hut, and probably also the epeditioners’ lungs! The mummified corpse of a seal, presumably brought to the hut to use as a fuel source, still lies outside. It’s extremely well preserved, given that it’s been lying exposed to the elements for over a century. It almost looks like it’s smiling.
On a knoll that overlooks the hut is Vince's Cross, a wooden cross erected in 1902 to commemorate Seaman George T. Vince. He died after falling down a steep slope and into the water during a blizzard.
I’ve had some questions about what it is we’re trying to achieve here, so I thought I’d say a few words about that. The purpose of our work here is to establish a robust, long-term history of past Antarctic ice sheet variation and climate evolution. Results will provide a context, or a baseline, for understanding current and future climate change. The Antarctic was chosen because the poles are most sensitive to climate change. In other words, global climate changes are typically seen first and most obviously at the poles and later and less obviously at the lower latitudes.
To achieve our objective, we are drilling a 1000 meter deep drillcore into the sedimentary layers that lie in the Ross Sea. The figure above shows the type of drilling rig we’re using. It’s set up on the sea ice about 35 km from McMurdo Station (I’ll be visiting it later this week, and will post pictures then). We anticipate sampling sediments that range in age from 0 to 17 million years. Environmental conditions in the spot where we’re drilling will be reflected in the sediments we recover. As will drill more deeply and back through time, changes in the types of sediments we recover will record things like changes in the amount of sea ice, the proximity of glaciers and, by proxy, climate.
Our team includes the following types of geologists:Sedimentologists, who describe the core and provide an interpretation of depositional environment;
Petrographers and geochemists, who examine the chemical composition of the sediments and the waters contained in the sediments. These data provide information about the source regions of glaciers and the type of weathering regime; Paleontologists, who examine the fossils contained in the core. Their data will provide information about the age of the sediments and changes in local ecology that often relate to climate change; and
Geophysicists, who study the physical properties of the core.
I am part of the geochemistry team. My role is to extract and analyze the waters that are contained in the sediments. These are waters that are buried along with the sediments. Most often, the water is seawater. However, we know that the glaciers have advanced and retreated several times in this region. As such, we also expect to find glacial meltwaters buried in certain sediment layers. I extract the water, which is held in the pore space of the sediment, by squeezing samples of the sediment in a metal piston using a hydraulic press. The water comes out a small hole in the base of the piston, and it is collected in a syringe. Yes, that’s me in the second picture, squeezing the bejeezus out of a sediment sample. Using the press, I can apply up to 40,000 pounds of pressure. So far I’ve been getting about 30 ml of water out of sediment sample that is 125 cc. I’ll get less and less as we drill more deeply and the sediment becomes more and more compacted.
Do you like the lab coat? I found it in the supply closet and just had to have it. With everything down here white and gray, a little color is a nice thing.
I thought I’d take the opportunity afforded by having to stay up all night to fill you in on the local geography. The image above, assuming it is readable on your screen, is a landsat image of the local region. The inset of Antarctica shows the approximate location of the landsat image. McMurdo Station sits on the end of a southward-pointing peninsula of Ross Island.
Ross Island comprises three volcanoes, namely Mt. Erebus (3794 m), which is still active, Mt. Terror (3230 m), and Mt. Bird. Ross Island served as the base for many of the early Antarctic expeditions, as it is the southernmost island that can be accessed by sea. Some of the huts built by the early expeditioners (Scott and Shackleton) still stand and are preserved as historical sites. McMurdo Station looks out across the sound toward the Royal Society Range.
I have a fantastic view to the south out of my lab/office window, from which I can see Black Island, White Island, Mt. Discovery, Mt. Warning, and up toward the Scott Coast. The view changes daily. Sometimes it’s so clear that I can see beyond Mt. Discovery and Mt. Morning. There have been other times, however, when blowing snow makes it difficult to see anything beyond the shoreline, which is located about 400 m from my window. The photo above doesn't do the scene justice, but gives a general idea of the view on a clear day. Just try to look beyond the buildings in the foreground.
