Topo Base Maps

This week I want to talk about what has gone into the creation of the maps that are illustrated in The Roof at the Bottom of the World. The base maps were produced by the U. S. Geological Survey after the International Geophysical Year (1957-1958), in a rush of activity that charted the entire length of the Transantarctic Mountains at a scale of 1:250,000. Combining aerial photography with ground control, the first printed quadrangles were published in 1959. Topographic engineers who created the initial ground control accompanied overland traverses or utilized helicopter support in coastal areas. Over the next five years, six to eight new maps were added annually to the portfolio of the Transantarctic Mountains. In 1964, the Topographic Division produced an astonishing twenty-four 1:250,000 sheets, covering all the bedrock outcrops of the Transantarctic Mountains, except for five quadrangles, which were published the following year. This bonanza followed a remarkable pair of seasons (1961-1962 and 1962-1963), during which a crew of topographers supported by a pair of Army helicopters surveyed the entire 1,500-mile length of the Transantarctic Mountains. In the book, I tell the story of these campaigns for the first time. During the period of peak productivity, the personnel at the Topographic Division assigned to the Antarctic quadrangles grew to about 180 participants. The teams split the tasks that included careful measurement and marking of peaks on aerial photos, linking summits to ground control, transferring points to a scribe sheet, measuring and drafting in contour lines, distinguishing ice from rock, adding color, outlining crevasse fields and moraines, air-brushing shaded relief, and inserting geographic names--all the while checking and rechecking everything for accuracy. The contour interval (the elevation difference between lines on the map) of these maps is 200 meters. This interval is very coarse when it comes to reckoning on the ground, but cartographers added air-brushed, shaded relief depicting the landscape to a detail that far surpasses that which can be read from the contour lines alone. With burnt siena bedrock, pale blue ice, and the sun perpetually shining in a northwestern sky, the air-brush rendering has provided a magnificent base map for tracing of the routes of the explorers, showing precisely where they traveled into the mountains, through crevasse fields, around ridges, over passes, up outlet glaciers, and onto the polar plateau. In the 1990’s the USGS scanned all of the 1:250,000 quadrangles into digital format and made them available to the public.

Franklin Island Quadrangle, 1:250,000, U. S. Geological Survey. Note that only the southwestern corner of the quadrangle was used.

For the figures in the book I merged those quadrangles that covered the area that I wanted to show. The USGS provides digital copies of the quads with both the margins intact and with them stripped away so that one can collage the quads seamlessly. But even though the merger is quite exact, the colors of the original, printed maps varied in some cases, so this shows up in the scans.

The Granite Harbour area combining four quadrangles, clockwise from upper left: Convoy Range, Franklin Island, Ross Island, and Taylor Glacier.

Once the collage was complete, I cropped the map to the size that I wanted. The next step was to Photoshop out all of the geographical names, producing a clean base upon which to work.

Granite Harbour area, cropped and geographic names removed.

Next I re-inserted names for those places mentioned in the book.

Granite Harbour area with geographic names re-inserted. Note that the outline of the Mackay Glacier Tongue shows its size in 1910-11 according to the map by Taylor that follows.

Finally, I drew in the traverse routes of the explorers using Adobe Illustrator. In some cases I composed the routes by a careful reading of the original accounts, but in others I was able to follow maps made by the explorers that showed the routes they took; for example, the map that follows by Griffith Taylor.

Granite Harbour area with explorers' routes and legend. The missing line on the left side of the Legend was corrected during final editing at Yale University Press.

Granite Harbour as mapped by Griffith Taylor following exploration during the 1911-12 field season.

Gallery – Zipper Ice

Straddling the boundary between northern and southern Victoria Land, Terra Nova Bay is home to open water during a longer period of the year than anywhere else along the Victoria Land coast. This is due to persistent katabatic winds (cold, gravity-driven winds) that pour down David Glacier and open the bay. In November of 1980, I observed an unusual phenomenon in this area. A thin sheet of ice had recently frozen over the open water. (I don’t know how thick, since we were at about 30,000 feet, but probably only a foot or two at most.) Some sort of pressure (currents or wind?) pushed the ice to the point of fracturing, but instead of a clean line with one side of the ice overriding the other, in this case each side took turns at being the one that rode over the other. I have heard this called “zipper ice,” though a quick trip to Google produced no hits for this feature. If you have a reference to zipper ice or have seen it let me know.

Stump’s Tent Camp

For field work in the Transantarctic Mountains, whether you are placed there by helicopter from McMurdo Station, operate within the perimeter of a remote helicopter and Twin Otter supported field camp, or are placed in the deep field by fixed-wing aircraft, you will be living in some sort of camp. The design of a field camp varies with the size and requirements of the party and with the personal preferences of the occupants.

On their southery traverse in 1902-03, Scott, Wilson, and Shackleton shared the pyramidal tent that has come to bear Scott's name. (Photo from Scott's book, The Voyage of the Discovery, 1905.)

This is how I like to set up a camp. The centerpiece of the camp is a Scott tent, that stalwart of design that has been with us since Scott used in during the 1901-04 “Discovery” expedition. With their four-sided pyramidal shape, the Scott tents of today cover a footprint 9x9 feet square with a similar height. The poles are heavy-duty, single-pieced aluminum tubes, hinged together at the top. The tent is double-walled without a bottom, but with a flap that extends out as an apron onto the snow. You cover this with snow blocks (or in the worst case, rocks) to hold the tent down, which works splendidly in the hardest winds. The poles extend about a foot into the snow beneath the level of the flaps. The tunnel entrance to the tent is a circular hole encircled by a tube of fabric that can be cinched down once a person has gone through. To me, the ideal number for a deep-field party is four. Each party member has their own sleeping tent and a Scott tent serves as the communal cook tent. What I like to do is dig out the bottom and use rock boxes as seats. (Rock boxes are a USAP standard, 12x12x18-inch boxes made of 1/2 inch plywood, with rope handles at the end.) The party members face each other, two and two. Because the floor is sunken we do not have to lean in (as much) beneath the sides of the tent. An ensolite pad helps to soften the seat. At the end opposite the entrance is the kitchen, which amounts to a set of rock boxes used as shelves and support for a Coleman stove. At the top of the tent is a flue made of a three-inch plastic tube that lets out steam and heat produced on the stove.

Interior of cook tent. Paul, on the left, looks up from a little light readng. Mugs holds a spatula, about to take the pancake out of the skillet on the stove. (1987-88)

In the 1970’s and early 80’s the individual sleeping tents (Meade tents) had a low wall and were A-frames with four poles at the ends. By the late 1980’s the personal tents were domes made by Sierra Designs.

Camp in the Gothic Moutains, January, 1981, Meade tents, a Scott tent, Nansen sleds, and Alpine 660 Ski-doos.

During the 1987-88 season, Paul Fitzgerald and I had a project in the Scott Glacier area that required climbing and collecting peaks with the highest relief that we could find. (The science of it is a story for another time.) Paul was a New Zealander who had just finished a PhD at the University of Melbourne using a technique called fission-track dating to determine the uplift history of the Transantarctic Mountains in the McMurdo Sound area. Because of the amount of climbing that we planned to do, we had two mountaineers with the party instead of the usual one. One was my brother Mugs, the other Lyle Dean. After the Herc had left us we set up camp, all of the tents strung out in a line perpendicular to the direction of the prevailing wind, with the cook tent in the middle. After setting up the cooking area, I started to melt snow for a brew, Earl Grey if I recall. The others piled into the tent in turn. This was 1987, we each had a Sony Walkman, and even I had caught up with the times. But I hadn’t seen nothin yet. As they sat down, both Lyle and Mugs whipped out a pair of small speakers boosted by C batteries that played off the Walkman. We hung the speakers about 2/3 of the way up in the corners of the tent producing a stereo quadraphonic sound space. Picture it. There we were in the middle of Antarctica, 600 miles from McMurdo, listening to cassettes we'd brought from the outside world. One of the favorite albums that season was Graceland recently released by Paul Simon. A line from The Boy in the Bubble spoke aptly to our situation and has stayed with me ever since: "These are the days of miracle and wonder." In the lead-up to the 2000-01 field season, I was requesting gear for a camp to the south of Byrd Glacier. I had not been to the Ice in 10 years and the manager of the BFC (Berg Field Center, the field party staging area in McMurdo) suggested that I might want to substitute the new Endurance tent for the Scott. It was about the same weight (60-70 lbs) she said, but had a footprint that was about three times bigger. I said, Okay. However, when I arrived in McMurdo, we added four folding aluminum chairs and two folding tables, one for cooking, the other for eating and laying out maps. Then I was reminded that the floor of the tent might sag under the pressure of the tables and chairs, so we also had to take along several 4x8 sheets of 3/4 inch plywood for a floor. By the time everything was assembled, the tent set-up probably weighed three or four times more than a Scott tent. There had been a time when I’d had a reputation for travelling light.

Camp south of Byrd Glacier, December 2000. The large tent in the foreground is an Endurance. Food boxes ring the upwind side of the tent. My sleeping tent is in the background.

For sure having a table and chairs is more comfortable (and we all grow older and creakier), but the tent was a very large space to heat with a Coleman stove, especially if there was a wind blowing outside. On a typical day we would come in from fieldwork, and fire up the stove to make water. Steam would fill the tent and at the end opposite the stove it would condense and freeze on the ceiling. If we continued to heat the space the ice invariably would melt and drip down on dinner or our maps. Enough said. Give me a Scott tent any day.

Gallery – Rocks in Ice

When rocks find themselves on glacier ice or the ice of meltwater ponds, an interesting phenomenon occurs. Due both to pressure melting from the weight of the rock, and the absorption of heat from sunlight on the warmest days of the year, the rock will melt its way into the ice, tunneling so deep sometimes that you can see the rock a foot or more below the surface.

The Silence

The Antarctic silence is mentioned by many of those who have travelled to the deep field. For example, Edward Wilson, Scott’s trailmate on both the first and second expeditions penned a poem called The Barrier Silence, which was published in The South Polar Times, printed at the winter quarters at Cape Evans: The silence was deep with a breath like sleep As our sled runners slid on the snow, But the fate-full fall of our fur-clad feet Struck mute like a silent blow On a questioning ‘Hush?’ as the settling crust Shrank shivering over the floe. And a voice that was thick from a soul that seemed sick Came back from the Barrier –‘Go! For the secrets hidden are all forbidden Till God means man to know.’ And this was the thought that the silence wrought, As it scorched and froze us through, That we were the men God meant to know The heart of the Barrier snow, By the heat of the sun, and the glow And the glare from the glistening floe. As it scorched and froze us through and through With the bite of the drifting snow.

Sundogs (parhelia) frame the sun across McMurdo Sound. The atmospheric phemomenon is caused by defraction of light at 23 degrees from the sun through rod shaped ice crystals settling through the atmosphere.

My own take on the Antarctic silence comes from The Roof at the Bottom of the World. During my first Antarctic field season (1970–1971), I worked from a remote field camp on McGregor Glacier, a tributary to Shackleton Glacier midway along its east side. I arrived on a ski-fitted Hercules C-130 aircraft that set down on McGregor Glacier. When I got off the plane, I was ending a long series of flights that had begun three weeks earlier in Quonset Point, Rhode Island, on the other side of the world. Three navy helicopters arrived the next day. They would serve the camp, tasked with putting out field parties in the morning and then picking them up at the end of the day to bring us back to base camp, where we would sleep and eat. Two days after I arrived I was flying out to my first day in the field. My excitement was acute. I had picked a site about eight miles north of camp, a small island of rock on the eastern side of Shackleton Glacier named Taylor Nunatak. The helicopter dropped Phil Colbert and me, along with our survival gear, and flew away. Its rotor faded and then was no more. For the first time in weeks, I was without the audible vibe of engines, whether screaming from aircraft or just humming to themselves somewhere in the background, quietly unnoticed. It wasn’t apparent at first, for as Phil and I scurried over to the margin of the glacier, we generated sounds of our own—footsteps, the click of our ice axes, the swish of our clothes. We stopped on a terrace of rock and looked out at Shackleton Glacier across a spectacular ice fall that gave the appearance of rapids in a wild river, except that it was motionless. Standing there, I suddenly became aware of the silence. It was behind me just at my shoulder. It went beyond the icefall as far as I could see. It was out there everywhere. The stillness was profound. The soft rustling of my parka seemed amplified. I held stone still. The sound of breath issuing through my nostrils filled my ears. I held my breath. The silence pressed in on all sides. It was palpable In my state of auditory suspension the icefall before me was all the more dramatic. It occurred at a point where a small ridge of rock projected from Taylor Nunatak into Shackleton Glacier. The glacier margin first reared up over this obstacle, broke into a jumble of blue seracs (ice blocks), then plunged chaotically down a steep, two hundred–foot scoop at the margin of the glacier, before molding smoothly back into the flow. In human time the icefall was a static sculpture of Nature’s grand design, in glacier time (moving about five feet per day) it was a rapids in a smoothly flowing river. As Phil and I stood there savoring our solitude, a sudden thwack broke the silence, like the shot of a .22-caliber rifle. We jumped and looked around, but there was no apparent source of the sound. A couple of minutes later another shot rang out. This time we were sure that it had come from the direction of the ice fall. Then it happened again. The ice was popping, strained to its limit and fracturing, incrementally working its way down the gradient at less than a millimeter per pop. The ice fall defied the silence. The dead air sucked up its sound. At last I was really out there, out there in a state of extreme isolation, even grace, with raw Nature everywhere on display. It was time to see what secrets the rocks would tell, and we went clomping up the outcrop, challenging the silence at every step.

Silence pervades pressure ridges in ice at the margin of Ross Island. Mount Discovery stands mute across McMurdo Sound.

Gallery – Sastrugi

Sastrigi is the name given to wind-blown patterns in snow, formed by the continuing processes of deposition and erosion of snow. The phenomenon is pervasive, producing a limitless variety of windswept patterns, begging to be framed.

Sastrugi in the Duncan Mountains

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