National Geographic : 1998 Oct
Sometimes the nuances of scene and time were so immense they were staggering. Once, when I was hiking with Jamie Pierce, a moun taineer with experience on all seven con tinents, he stopped, looked around, and gave up trying to take it all in. "My mind's on over load," he said. "This is, like, nuts." Above us was a steep tumble of ice where the ice sheet of the Antarctic interior falls across the ridges and drops a blue puddle called the Wright Upper Glacier into the edge of the Dry Valleys. The falls are called Airdevronsix Ice falls after the Navy squadron that has worked in Antarctica since 1956. This was a Niagara of ice, but much bigger. It was over three miles wide and more than 500 feet high. Huge chunks of ice cascaded down the falls; it looked as if New York City had been turned into salt blocks and shoved into the Grand Canyon. But the thing that really got me was that no matter how long I looked at it, nothing moved. I watched and watched. The blocks were impossibly tilted, the angle impossibly steep. Things should be tumbling, crashing, thunder ing. But nothing moved. Time was roaring along out there, but we couldn't hear it. J IVE DEGREES RIGHT!" Dave Marchant said into his headset's mike as a National Science Foundation helicopter clattered up a valley tiled with polygons created in loose rock by the flexing of frost. "Five degrees left! There! That's all Pleistocene there. Ten left!" Marchant is a geologist from Boston Univer sity. He's a time detective. Marchant's current specialty is using volcanic ash to study the age of landscapes. Since ash can be dated more accurately than most other ancient materials because of the way isotopes in it mark the time passed since it was formed, any ash found where it fell is a tag marking the flow of time. Marchant's tags have become critical lately because of a new theory that the deep sheet of ice that covers East Antarctica melted away as recently as three million years ago. This may not seem exactly yesterday, but in the Dry Val leys context it's just a couple of moments past. This idea would mean that Antarctica's entire ice cover is much more unstable than previous theories would have it. The bottom line is this: If the Antarctic ice sheet, which holds as much as 70 percent of the TIMELESS VALLEYS OF THE ANTARCTIC DESERT world's fresh water, is that prone to melt, then global warming could raise sea levels by feet instead of inches, inundating coastlines around the world. Marchant and others do not agree with this theory. Because the ash has been where it landed for far more than three million years, he thinks the Dry Valleys-and the adjacent ice sheet-have been much as they are for a lot longer than the melt theory would allow. One morning when a blizzard kept us in camp, Marchant read me a short poem he wrote years ago: By the questions we pose Ourselves we deceive So limited in thought By what we choose to perceive. Marchant laughed at the poem but wanted me to take it seriously. Its edge-a warning about blind spots in science-is his reaction to the debate about melting. LaterheandIsatonarockinavalleyof polished desert stones, and he talked about how rocks here are shaped by the brush of wind and the slow interaction of moisture and chemicals. "A drop of water forms on the rock," he said. "Every drop carries dissolved salt from the sea. The drop slides under the rock and falls off. Thousands of years later, and there's a grain of salt. Any stone probably has millions of years of salt under it." I picked up a flat stone. Under it was a little heap of salt. I felt as if I had disturbed the sleep of something. I put the rock back. That salt was eerie. It reminded me of the dead seals and of the skull-shaped rocks behind Bruce Marsh's camp. This whole place is like an ancient skull, I thought, once a piece of the vibrant life of the Earth, now abandoned by the warmth and wetness that keeps the rest of the planet teeming with life. This skull is dried out and left to bleach, but we can pick it up off the ground where it's been lying for ten million years, stare like Hamlet into its strangely expressive shadow eyes, and know that there are many things hidden in time that we have yet to learn. Marchant grinned at my amazement. He'd seen the Dry Valleys do this to others too. "First you think there's nothing here, don't you?" he said. "Then there is too much."