A Wilder Time Page 12
AS LUNCHTIME ARRIVES, WE PACK UP our samples and head east, hoping to find a place where we can explore the actual ice front, for a little while. But about half a mile from that massive ice wall, the opaque fjord waters become thick with silt. Conditions like these can sometimes hide water-saturated mud shoals under a veil of water a few inches deep. Running into such a thing would ground us in the middle of the fjord, with a real possibility that we might not be able to get the Zodiac out. As a precaution, John turns sharply toward the northern shore and lands us there.
We find a small grassy ledge and settle in to eat lunch and watch the ice. Despite the distance, the view is spectacular. A buttress of broken ice blocks lies at the base of the ice face, testimony to a long history of icefalls and avalanches. From that jumbled chaos, small ice blocks float away at high tide, filling the water in front of us with an infinite variety of shapes lazily flowing with the current. Gulls are all around, bobbing in the frigid water. Every now and then, one of them takes flight and lands on an ice block and casually sails by us out into the fjord, then abandons its carrier and flies back for another ride. Many gulls do that repeatedly—whether it is some effort to entice us to feed them, which we don’t, or if they are just having fun, is never clear.
I have always wondered what it would be like to ride an iceberg—what the surface is like, how buoyant it might be, what the touch of one would feel like. I mention this to Kai and John and we debate what to do. Finally, it’s decided we will take a few minutes to try getting me onto one of the frozen blocks floating by.
We finish lunch and pack up.
But before we leave, John reaches into his backpack and pulls out his camera. Handing it to me, he asks in a slightly sheepish tone if I will take a picture of him in front of the ice. He walks over to the edge of the little bench we are on. In the background, the massive front of the Greenland ice sheet glares in brilliant white in the noontime sun. Standing tall, with his head back a bit, John stuffs his hands in his pants pockets, turns slightly toward the ice, and says, “Now.”
We each take turns posing.
Then we load up the boat and sail out into the fjord toward one of the ice blocks. It is about ten feet long and five wide. At the water’s edge, the melting of the small berg has carved a scalloped, rimming incision. Above that, a narrow ledge surrounds the block that bounds sculpted, delicately laced ice ridges, fingers, and hummocks. The surface is like an intentionally carved sculpture garden of abstract forms that are slowly, invisibly melting.
I ask John to get next to it so that I can see if I can get on it. Gingerly, he navigates the Zodiac to the edge and tries to keep it there.
The surface sparkles in the sun, carpeted with a network of tiny ice crystals that form an interlocking, fragile transparency. With care, I slide onto the Zodiac pontoon and put a foot on the tiny iceberg. The crystal network shatters under my boot and immediately the ice begins to roll, bumping into the boat. It is unexpectedly delicately balanced. Since we have no idea what its underwater form is like, and whether or not it can tip us if it rolls, we quickly back away and let it float off.
We spend the rest of the day on the south side of the fjord, then start back toward camp. A modest wind has come up, blowing against us, making for a slow and choppy journey.
ICE HAS NO PERMANENCE ON THIS PLANET, but its metamorphosis from snow to ice fields to massive calving ice walls is more than a shift in form. It alters light, shapes sounds using its own voice, and responds to touch. It is a separate world of experiences, one that is rich and deep. This I learned years ago, from a different setting, far from the water’s edge, at a place in Greenland where the ice sheet ended on land, miles from any fjord—a place where the experience of ice was more intimate. There, the distinction between ice and rock was, to some degree, arbitrary, and the experience of it a revelation.
It was a place miles east of Kangerlussuaq, a site I and a few other researchers had traveled to in an old army truck along a vague and winding dirt road. We drove to a small hill a few minutes’ walk from the edge of the ice sheet. The tundra biome carpeted the ground for some thirty feet in front of us, then abruptly ended where the advancing ice, a few years before, had scraped off the overlying soil and plants and then retreated, exposing a glistening rock surface that had been repeatedly sanded and polished by the ice for millennia.
We were at the southern end of a lobe in the ice cap. To our right, the ice was bounded by a moraine of rocks and dirt over fifty feet high that ran for many miles along the ice front. The moraine had been pushed up as the ice migrated over the land. But as climate change took hold and warmed the air, the ice was melting back and was barely in contact with its rimming moraine.
Directly in front of us was a huge ice amphitheater partially filled by jumbled blocks that had fallen from the ice face. To our left, hundreds of yards away, the amphitheater ended in another massive wall, in which there was an enormous ice cave. The cave extended back into the ice hundreds of feet. It was impossible to tell exactly how far back the ice cave reached, because its depths were blackened in deep shadow—it could have been a quarter of a mile or more. Inside the cave was a waterfall at least forty feet high that fed a river cascading down ice blocks covering the floor. The river rushed from the cave and flowed along the base of the wall in front us, a persistent liquid boundary between rock and ice.
Low rumbles, snaps and pops, and repeated booms came from the ice front. I walked closer to it, trying to figure out what was making the noise. I had imagined the place would be a silent whiteness, but the wall itself was a cacophony of sounds that pounded through a startlingly complex pattern in the ice of pale blues and ribbons of brown that laced through all shades of white.
The ice wall was water that had fallen from the sky thousands of years ago and hundreds of miles away to the east. After having been buried and compressed, it had recrystallized and sunk to near the base of the ice sheet, where it scraped up rock fragments from the bedrock and pulverized them to fine dust. Now, after slowly migrating a few inches per year, the frozen ice was exposed in the cliff in front of me, sunlight once again shining on the molecules of water that would soon be freed to flow in rivers to the sea and repeat the cycle. The booming, snapping, and popping was the voice of that frozen water as it scraped over the land, internally cracking into crevasses and fissures, preparing to be released.
After a while, we began to walk along the amphitheater. The maze of ice blocks was a jumbled chaos that would have been impossible to walk through. Some blocks were the size of fists, some the size of houses, and all of them were sharply angled and lying precariously in illogical arrangements. I turned to one of the researchers with me and started to say that I would love to see an icefall, when, at the back of the amphitheater, a loud cracking sound reverberated across the icescape.
Slowly, almost imperceptibly even, a huge section of the wall began to move. At first, the face simply seemed to shift slightly, with a few small pieces leaping in free fall off the wall. Time seemed to slow down, as it sometimes does when one is startled or threatened.
For what seemed like many seconds, but could not have been, I watched as the wall cracked and fractured and crumbled across the entire amphitheater’s face, cascading down in an accelerating free fall. With a tremendous explosion and roar, the ice smashed into the jumble of blocks at its base. Ice flew everywhere. Some of it bounced off blocks in the remnant pile of earlier collapses; some smashed into fragments and ricocheted off the ice front. A few pieces the size of baseballs flew out toward us, landing in the river and shattering on the polished bedrock around us. Then, within seconds, the drama was over and the roar from the fall died away. Ice dust, drifting as though it were fog carried in an early-evening breeze, drifted off in the air, and the scene, slightly rearranged, returned to the stillness it had been.
Scattered all around were sparkling jewels of shattered ice. I walked over to where there was a collection of them and picked one up. It was a single crysta
l of frozen water the size of a Ping-Pong ball, irregularly faceted by gently curved surfaces into a magical gem. It was perfectly clear, with fine trains of microscopic bubbles laced through it. The thinnest film of liquid water covered the smooth, irregular facets. I held the transparent nugget up toward the ice wall and looked through it like a lens, impressed by its brilliant clarity.
I put it in the palm of my hand and looked at it from all angles. The smoothness of the liquid surface begged to be tasted. I put it in my mouth.
Beyond the first impression of cold, the taste was almost exactly what the clarity of the ice implied it might be—clean, refreshing, soft. A feeling of calmness came with it. And then, startled, I realized there was an impression of smell. I breathed in and was immediately taken by a sensation of open sky, clean air, and earth. I took the ice out of my mouth and picked up another crystal. I brought it to my nose and smelled it. The experience was of something subtle but persistent, something that was fundamental—a thing that was nothing but its own essence. Flint and stones came to mind, along with graveled river edges and a very faint mustiness. It was a smell that brought out feelings deeply rooted in some old experiences of watery, lithic places. I kept inhaling, trying to capture the impressions, but they flitted away as quickly as they materialized.
The sense of smell is deeply imbedded in the wiring of the brain. The olfactory organs carry messages to the olfactory bulb, from whence information is transmitted that becomes part of our cognitive and subconscious experience. Although species-specific, the wiring of this circuitry is schematically similar for most animals. The wiring for smell seems to be something that evolution perfected early on—it has guided creatures for hundreds of millions of years. Could it be that part of that evolutionary schooling included learned lessons—that certain smells implied certain possibilities, good and bad, that would influence behavior? Was it possible that such sensitivities would be selected for, carried into future generations as a benefit for survival? Could one such lesson for humanity have been the smell of ice and its implications? Perhaps there is knowledge contained in that smell, knowledge of the danger of icefalls, of the possibility of woolly mammoths and food, of fish and berries, of marshy land and the annoyance of mosquitoes.
I imagined an ice wall bounding a Stone Age world. An Ice Age hunter would have tracked animals, searching for food in a primordial place. With others of his kind, he would have walked through places much like where I stood, and read the ice and the land, perceiving the dangers, and sensing where barren-ground caribou and mammoth and musk ox and fox might be. They would have found the right places to spend the night, protected from the wind and wet and cold, their tolerance for discomfort beyond anything I would ever know. They would have gathered plants on their journeys, and collected the right stones for shaping. They would have talked in some long-lost language.
It was a time of an unembellished Earth, when the wild character of land and life existed as an unconstrained stage across which humanity wandered and time was immaterial.
Seal
THE PURSUIT OF SCIENCE IS AN EXCAVATION. Insights gained through research expose unexpected layers of past histories richer in content than what we could possibly imagine.
After our third expedition, it was unequivocal that the shear zone was a scar, slashed across the northern edge of the collision terrain as a last act, a tectonic finale in a mountain-building drama. That scar was what the early researchers had claimed it was—a zone of major movement. Kai and John’s work was correct and the region reverted to the term they had used for it years before—shear zone replaced the straight belt moniker on later editions of geological maps and in publications.
But buried in the crystalline record, frozen in the minerals of a few rocks from small, scattered localities, was evidence that these rocks had descended into earth at least a hundred miles before the collision of continents began. That part of the story had been completely missed. Uncertainty had changed in form but not magnitude—new questions now had to be addressed.
One of those questions was the significance of the rocks that had been so deeply buried. Only a handful of places around the world had histories of so-called ultrahigh-pressure metamorphism—metamorphism under conditions where pressures were more than 400,000 pounds per square inch, a state that is achieved in the earth only at depths beyond sixty miles. The evidence in all those other locations came from ancient subduction zones. In every instance, those subduction zones marked locations where continents had collided and were thus consistent with the history that was suggested as a possibility in our study area in Greenland. But none of those other sites was older than 900 million years. Explanations varied for why all those other locations were so young compared to Earth’s four-and-a-half-billion-year age. Some believed that the inherent instability at the Earth’s surface of minerals formed at such high pressures would result in their slow but inevitable retrogression to other minerals, ones that were more stable at low pressure conditions. By that reasoning, it was concluded that about 900 million years was the maximum amount of time such unstable minerals could persist. Another explanation was that plate tectonics, with the ocean floor spreading and the subduction zones we see today, did not become completely established until about that time—earlier plate tectonics presumably were expressed through some other, and as yet unidentified, mechanisms, possibly involving much shallower convergence zones and no deep subduction. Whatever the explanation, we were faced with the challenge of explaining the uniquely old age of the ultrahigh-pressure rocks we had discovered. Since it was now clear that our samples had persisted for twice as long as their younger counterparts, they were either the products of some very unusual preservation mechanism or rare evidence of much older plate tectonics that has yet to be found in other settings. Given the unusual nature of the rocks we were studying, the answer almost certainly lay in a combination of both ideas.
Also clear was another puzzle. In a library of hundreds of samples that had been collected and studied by several different researchers over four decades, we had found two that preserved evidence of ultrahigh-pressure conditions. One reason why that evidence had not been previously recognized was that the mineral characteristics and compositions that indicate such conditions were not understood until recently. But the fact that we found a record of such conditions in only two samples out of the hundreds we reexamined raised another question. Did this mean that evidence of such extremes had been nearly completely obliterated by later events, like the late shearing, leaving a very small fraction of rocks that kept their history intact? Or was it evidence that the entire region was actually a tectonic jumble in which rocks from vastly different locations and histories had been forcefully interleaved with one another?
OUR FOURTH EXPEDITION IS AN EFFORT to better understand the new questions. We have decided we will spend a few weeks moving from campsite to campsite so that we can visit key localities that are scattered over a thousand square miles. Carsten, the owner of a small cabin cruiser in Aasiaat, has contracted with us to be our logistical support, moving us when we need to relocate, taking care of his boat at our campsites in the meantime.
One of the sites we’ve decided to visit is a place where John worked years before. It will be an eight-mile traverse; we will be hiking along exposures of marble that had been tectonically intermingled with very old gneisses. John had mapped this area while working on his doctorate, before plate tectonics models that embraced colliding continents were fully accepted. Back then, the conceptual paradigm was called “geosynclinal theory,” in which it was envisioned that huge basins hundreds of miles wide and thousands of miles long were scattered across the globe. Although they did not migrate across the face of the Earth as tectonic plates do, it was believed the basins would slowly subside, growing deeper and deeper with time. As they did so, they filled with sediments. Eventually, through unknown mechanisms, they reached an unstable state and compressed, with massive mountain systems growing out of them. Since the data
collected at the time were described using terms useful for the geosynclinal theory but incomplete for plate tectonic concepts, we wanted to look at the area in more detail to see how it might fit into the new picture of things.
Morning emerges gray and still. The cruise along the coast is calm and easy. We head toward the mouth of a small fjord, where we can land and start the traverse. The terrain will be uneven but not rugged—a hike that we can easily do in a day.
By the time we reach the fjord mouth, the tide is slack. The short trip from the boat to shore, using the small skiff that is tied to the stern, will be easy. Backpacks and hammers, food and water are tossed in. Then, just as we are getting ready to launch the skiff, the head of a seal pops up a few hundred yards off the starboard rail and somewhat astern. It watches us curiously, head high out of the water, keeping its distance. Carsten sees it immediately and becomes quite excited. He knows this could be dinner, a pelt and dried meat for his family.
He jumps off the skiff, runs to the cabin, and grabs a small-bore rifle that is mounted above the port door. He checks the chamber and loads the magazine, then runs back to the skiff and quickly takes us ashore. Although he attentively guides the skiff to our chosen landing spot, every few seconds he looks back over his shoulder, keeping an eye on the seal. Once we land, he races back to the boat and heads out after the seal, the rifle laid across the top of the instrument panel in front of the wheel. If all goes according to plan, we will meet up with him around suppertime, back at camp.
We immediately spot the marble outcrop we are looking for directly across the stony beach we have landed on. It is a medium gray color, about six feet thick, and sandwiched between brownish black gneisses. We hike along it, impressed by the intricately folded structures and stretched inclusions that embellish it—undeniable testament to extreme shearing. It is consistent with the strain rocks would go through if they were caught between massive continents grinding together in a collision zone—another stake in the ground.