Beacon Valley Camp, Antarctica
by Peter SmithJanuary 05, 2008 -
Winds whip like the devil across the eastern Antarctic ice sheet, freezing cold blasts that force the meteorite hunters who work on the ice to stay battened down in their tents while the wind screeches through the guy wires like banshees in the Welsh highlands. A recent story from a team that had to be evacuated was that the wind was rolling their snowmobiles across the ice. Beacon Valley borders the ice sheet and we see it cresting the mountain ridges at the western end of our valley. Today ice blows in billowy clouds over the edge of the canyon and rushes along its malicious way finding a path to the sea.
Our tents, perched on a ledge about 150 feet above the valley floor are taking a terrific beating and we have been driving extra stakes into the tie down points and tightening the guy wires holding our few possessions in place. At the same time our water supply has diminished to the level where we need to hike up the hill to a permanent snow bank to collect chunks of frozen ice and snow to melt over our Coleman stove. Without our gear we would quickly freeze and starve in this barren valley, the chances of hiking back to the safety of McMurdo are slim.
These are the katabatic winds according to our Antarctic expert, Chris McKay. He explains that the drop in altitude from the actual South Pole at 11,000 feet to our current site at 4,500 feet causes the air to compress as it moves to lower altitudes and higher pressures. Unconvincingly, he tells us that compression heats the air and that theses are warm winds. I am wearing all the clothing that I brought with me and wishing that I had brought more.
Despite the blustery, "warm" conditions 3 members of our group are exploring the valley with shovels in hand, digging trenches and gathering samples. Sam has set up his MECA wet chemistry laboratory in our cook tent. He has discovered and solved a tricky chemistry problem associated with his calibration solution. Half of our single table is chemistry lab and the other the kitchen. Hopefully, they don't unintentionally get mixed. Aaron also has his TECP apparatus in the same tent although he doesn't venture further than out the back door of the tent into the nearest available soil.
Doug has brought an X-ray diffraction device that is analogous to the ChemMin instrument on the next Mars mission called Mars Science Lab (MSL) that launches in 2009. He has demonstrated the power of this instrument several times by quickly identifying the minerals in unknown samples using this portable field instrument. Therefore, a sub-sample of the collected specimens can be quickly evaluated in our base camp on Phoenix ledge.
Our small aerie starts at the southern end with the heliport, the flattest ground in this portion of the ice-mounded, rocky terrain. As one strolls from the heliport past the cargo area a colorful group of tents of various and sundry shapes is evident. The first pyramidal tent is the chamber of horrors called the "poop tent." With a roof height of about 4 feet, one goes about the necessaries on hands and knees, the target is a bucket called "human waste."
Outside this tent are the two 55-gallon drums for other waste - gray water and urine. The environmental treaty conditions require no wastes or garbage to be disposed within the dry valleys. We are also careful to conceal any trenches or other modifications of the local landforms and provide the exact GPS coordinates to authorities at McMurdo. Next, is our common tent where we gather for hot drinks and discuss the day's activities. It is also our cook tent. This is called an Endurance tent and is 16 feet long and just high enough that I can stand, 6 feet 4 inches.
Our kitchen consists of a Coleman propane stove, a pantry, and an anti-refrigerator. You might wonder why kitchens everywhere do not have the advantage of an anti-refrigerator; it's because the peak temperatures at Beacon Valley are below freezing and all our water freezes. Therefore, we put a bottle of hot water inside a cooler and put everything that we don't want frozen inside. Frozen foods are left outside the tent in a box. Coolers also serve as chairs as well as the wooden food boxes.
The kitchen is ringed with paper towel racks. Water, a precious substance here in its liquid form, is not used for washing. Dishes are wiped immediately after use with a paper towel and each of us has our own canvas bag for storing our personal dishes and silverware. All meals are eaten to completion and pots wiped clean. We alternate dinner chefs every night and there are demerits for any waste water produced; this makes pasta a rare dish. But you need to understand that our only source of water is the snow bank about 50 yards up a steep hill then a long process of melting on the stove. On the other hand, drinking lots of fluids is encouraged in this ultra-dry environment.
Surrounding the central kitchen/lab tent is the bedroom community of small sleeping tents. We each have an extra-warm sleeping bag on a small cot with two thermal protection mats underneath. Using a two-person tent for one person allows storage of all the cold weather gear that we brought from Christchurch. On the coldest days we wear our "Big Red," a thick extreme-weather coat with a fur-lined hood and wind pants that cover our clothes. Layer clothing is the common wisdom and I typically wear 5 to 6 layers.
Sam and Doug are digging trenches, Susanne is across the valley at the sandstone wall looking at endoliths, bacterial communities that live in the rocks. Chris gets a call on the radio and goes down to visit the latest trench while Aaron and I continue melting ice to prepare our water supply for the next few days. All of a sudden the sound of a helo tells us we have visitors. We contact them by radio and prepare the helipad.
Because the strong winds are coming down valley, the helo has to approach the landing site directly across our camp. This was not appreciated when we set up the camp and is definitely a mistake. The prop wash comes straight across our tents blowing out the poop tent supports and sending the rock-weighted urine funnel, the entrance to the 55-gallon drum, zinging down the hill at about 20 mph. We are in great danger of violating environmental protocols.
Scientists Ron Sletten and Birgit Hagedorn have arrived with their team of three. They are long-term dry valley experts and have studied the ground and soil characteristics and local weather conditions for years. We will have a unique chance to learn from their combined experience and share our interpretations with their group. But first we have to find the darn pee funnel.
Later, funnel retrieved, poop tent reconstructed and more wind-resistant, we discuss our experiences with the new group. Eventually, we have 11 people crammed into our cook tent, very cozy so we invite them to dinner later. We will tell them about our adventures in University Valley.
The soils of University Valley, a hanging valley upslope from our camp, are formed from the vertical cliffs of sandstone intruded with dolorite (a dark, igneous rock) that form a horseshoe with a permanent ice field at the far end. Trenches transecting from the base of the ice out about a kilometer away show soil originating from the local rocks and a progressively deeper ice table. Apparently, the snow blown into the valley from the ice sheet above disperses onto the valley floor starting from the ice field out to a region that never receives any snow. Perhaps this explains the greater depths to ice, Sletten and team can help us answer this question by measuring the salts and ice isotopes as they have done in other dry valleys.
We are getting close here to the type of science that we plan to do on Mars: to characterize the history of our site and source of the subsurface ice by measuring the chemistry (particularly the salt content), the mineralogy (those altered by the presence of unfrozen water), isotopic ratios of key elements, and the microscopic textures of the soils. Our discussions about the processes at work in the dry valleys are similar to those we will have once data is gathered from the Martian soils. Today there is so little known about Martian soils that it is hard to base hypotheses on facts.
In comparison, the Arctic permafrost is much warmer and wetter than here in the south, and the vegetation and animal life allow human communities to survive as they have for more than 10,000 years. The Antarctic coastal valleys are much more severe with no large plant life and few animals, the penguins can't even survive here; however, the ground is wet in the summer and lakes can form from local glaciers. As we move inland and up in altitude, the weather is even more severe and no lakes are found. The ground is dry even when below freezing - dry permafrost. There is occasional snowmelt in the summers that quickly seeps into the ground on the warmest days; this is the cause of weathering of the rocks as the water chemically alters the rock faces.
Water and ionized air can combine to make salts that are transported around to the underside of the rock eventually forming what are called horizons beneath the surface. The snowmelt water also oxidizes the iron in the rock and reddens the soil. The rocks weaken from this chemical attack and from the temperature cycles found in this environment. A walk around the valley is like touring a geology classroom with rocks shaped by the strong winds and broken along internal fractures that become wet then freeze. Salts also grow crystal inside the cracks and the force of their growth is stronger than the rock splitting them open and rocks can be turned to rubble in place. There is no central stream in this valley; all erosion happens slowly through subtle but ruthless processes.
From the wet Arctic to the range of conditions in the Antarctic to the much drier and colder conditions on Mars is a stepwise progression. The winter ice that covers our landing site is predominantly carbon dioxide ice as the atmosphere actually freezes onto the cold surface. We wonder if there is a small amount of water ice mixed in that may turn liquid under optimum conditions in the spring and begin an Antarctic-like process of weathering the rocks. Or can climate change on Mars over periods of 50,000 to 100,000 years create conditions more conducive for ice to melt? If so, we expect to see changes in the soil that are reminiscent of our trench studies in Antarctica.