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In Suspect Terrainby John Mcphee
In Suspect Terrain
The paragraph that follows is an encapsulated history of the eastern United States, according to plate-tectonic theory and glacial geology.
About a thousand million years ago, a continent of unknown dimensions was rifted apart, creating an ancestral ocean more or less where the Atlantic is now. The older ocean has been called Iapetus, because Iapetus was the father of Atlas, for whom the Atlantic is named. Some geologists, who may feel that their science is dangerously clever, are snappish about Iapetus. They prefer to say proto-Atlantic. The ancestral ocean existed a great deal longer than the Atlantic has, but gradually, across some two hundred and fifty million years in the Paleozoic era, it closed. Moving toward each other, the great landmasses on either side buckled and downwarped the continental shelves and then came together in a crash no lessbrutal than slow--a continent-to-continent collision marked by an alpine welt, which has reached its old age as the Appalachian Mountains. In the Mesozoic era, two hundred million years ago, rifting began again, pulling apart certain segments of the mountain chain, creating fault-block basins--remnants of which are the Connecticut River Valley, central New Jersey, the Gettysburg battlefields, the Culpeper Basin--and eventually parting the earth's crust enough to start a new ocean, which is now three thousand miles wide and is still growing. Meanwhile, a rhythm of glaciation has been established in what is essentially the geologic present. Ice sheets have been forming on either side of Hudson Bay and have spread in every direction to cover virtually all of Canada, New England, New York, and much of New Jersey, Pennsylvania, and the Middle West. The ice has come and gone at least a dozen times, in cycles that seem to require about a hundred thousand years, and, judging by other periods of glaciation in the earlier history of the earth, the contemporary cycles have only begun. About fifty more advances can be expected. Some geologists have attempted to isolate the time in all time that runs ten thousand years from the Cro-Magnons beside the melting ice to the maternity wards of the here and now by calling it the Holocene epoch, with the implication that this is our time and place, and the Pleistocene--the "Ice Age"--is all behind us. The Holocene appears to be nothing more than a relatively deglaciated interval.It will last until a glacier two miles thick plucks up Toronto and deposits it in Tennessee. If that seems unlikely, it is only because the most southerly reach of the Pleistocene ice fields to date stopped seventy-five miles shy of Tennessee.
Anita Harris is a geologist who does not accept all that is written in that paragraph. She is cool toward aspects of plate tectonics, the novel theory of the earth that explains mountain belts and volcanic islands, ocean ridges and abyssal plains, the deep earthquakes of Alaska and the shallow earthquakes of a fault like the San Andreas as components of a unified narrative, wherein the shell of the earth is divided into segments of varying size, which separate to form oceans, collide to make mountains, and slide by one another causing buildings to fall. In a revolutionary manner, plate-tectonic theory burst forth in the nineteen-sixties, and Anita Harris is worried now that the theory is taught perhaps too glibly in schools. In her words: "It's important for people to know that not everybody believes in it. In many colleges, it's all they teach. The plate-tectonics boys move continents around like crazy. They publish papers every year revising their conclusions. They say that a continental landmass up against the eastern edge of North America produced the Appalachians. I know about some of the geology there, and what they say about it is wrong. I don't say they're wrong everywhere. I'm open-minded. Too often, though, plate tectonics is oversimplified and overapplied.I get all heated up when some sweet young thing with three geology courses tells me about global tectonics, never having gone on a field trip to look at a rock."
As she made these comments, she was travelling west on Interstate 80, approaching Indiana on a gray April morning. She had brought me along to "do geology," as geologists like to say--to see the countryside as she discerned it. Across New Jersey, Pennsylvania, and Ohio, she had been collecting, among other things, limestones and dolomites for their contained conodonts, index fossils from the Paleozoic, whose extraordinary utility in oil and gas exploration had been her discovery, with the result that Mobil and Chevron, Amoco and Arco, Chinese and Norwegians had appeared at her door. She was driving, and she wore a railroad engineer's striped hat, a wool shirt, bluejeans, and old split hiking boots--hydrochloric acid for testing limestones and dolomites in a phial in a case on her hip. With her high cheekbones, her assertive brown eyes, her long dark hair in twin ponytails, she somehow suggested an American aborigine. Of middle height, early middle age, she had been married twice--first to a northern-Appalachian geologist, and now to a southern-Appalachian geologist. She was born on Coney Island and grew up in a tenement in Williamsburg Brooklyn. There was not a little Flatbush in her manner, soul, and speech. Her father was Russian, and his name in the old country was HerschelLitvak. In Brooklyn, he called himself Harry Fishman, and sometimes Harry Block. According to his daughter, English names meant nothing to Russian Jews in Brooklyn. She grew up Fishman and became in marriage Epstein and Harris, signing her geology with her various names and imparting some difficulty to followers of her professional papers. With her permission, I will call her Anita, and let the rest of the baggage go. Straightforwardly, as a student, she went into geology because geology was a means of escaping the ghetto. "I knew that if I went into geology I would never have to live in New York City," she once said to me. "It was a way to get out." She was nineteen years old when she was graduated from Brooklyn College. She remembers how pleased and astounded she was to learn that she could be paid "for walking around in mountains." Paid now by the United States Geological Survey, she has walked uncounted mountains.
After the level farmlands of northwestern Ohio, the interstate climbed into surprising terrain--surprising enough to cause Anita to suspend her attack on plate tectonics. Hills appeared. They were steep in pitch. The country resembled New England, a confused and thus beautiful topography of forested ridges and natural lakes, stone fences, bunkers and bogs, cobbles and boulders under maples and oaks: Indiana. Rough and semi-mountainous, this corner of Indiana was giving the hummocky lie to the reputed flatness of the Middle West. Set firmly on the craton--the Stable Interior Craton, unstirring core of the continent--the whole of Middle America is structurally becalmed. Its basement is coated with layers of rock that are virtually flat and have never experienced folding, let alone upheaval. All the more exotic, then, were these abrupt disordered hills. Evidently superimposed, they almost seemed to have been created by the state legislature to relieve Indiana. Not until the nineteenth century did people figure out whence such terrain had come, and how and why. "Look close at those boulders and you'll see a lot of strangers," Anita remarked. "Red jasper conglomerates. Granite gneiss. Basalt. None of those are from anywhere near here. They're Canadian. They have been transported hundreds of miles."
The ice sheets of the present era, in their successive spreadings overland, have borne immense freight--rock they pluck up, shear off, rip from the country as they move. They grind much of it into gravel, sand, silt, and clay. When the ice melts, it gives up its cargo, dumping it by the trillions of tons. The most recent advance has been called the Wisconsinan ice sheet, because its effects are well displayed in Wisconsin. Its effects, for all that, are not unimpressive in New York. The glacier dumped Long Island where it is (nearly a hundred per cent of Long Island), and Nantucket, and Cape Cod, and all but the west end of Martha's Vineyard. Wherever the ice stopped and began to melt back, it signed its retreat with terminal moraines--huge accumulationsof undifferentiated rock, sand, gravel, and clay. The ice stopped at Perth Amboy, Metuchen, North Plainfield, Madison, Morristown--leaving a sinuous, morainal, lobate line that not only connects these New Jersey towns but keeps on going to the Rocky Mountains. West of Morristown, old crystalline rock from the earth's basement--long ago compressed, distorted, and partially melted, driven upward and westward in the Appalachian upheavals--stands now in successive ridges, which are called the New Jersey Highlands. They trend northeast-southwest. With a notable exception, they have discouraged east-west construction of roads. When the last ice sheet set down its terminal moraine, it built causeways from one ridge to another, on which Interstate 80 rides west. Over the continent, the ice had spread southward about as evenly as spilled milk, and there is great irregularity in its line of maximum advance. South of Buffalo, it failed to reach Pennsylvania, but it plunged deep into Ohio, Indiana, Illinois. The ice sheets set up and started Niagara Falls. They moved the Ohio River. They dug the Great Lakes. The ice melted back in stages. Pausing here and there in temporary equilibrium, it sometimes readvanced before continuing its retreat to the north. Wherever these pauses occurred, as in northeastern Indiana, boulders and cobbles and sand and gravel piled up in prodigal quantity--a cadence of recessional moraines, hills of rock debris. The material, heterogeneous and unsorted, has its own style of fabric, in whichgeologists can see the moves and hesitations of the ice, not to mention its weight and velocity. Scottish farmers, long before they had any idea what had laid such material upon Scotland, called it till, by which they meant to convey a sense of "ungenial subsoil," of coarse obdurate land.
"This would be a good place for a golf course," Anita remarked, and scarcely had she uttered the words than--after driving two thousand yards on down the road with a dogleg to the left--we were running parallel to the fairways of a somnolent St. Andrews, beyond reach of the sea wind, with natural bunkers and traps of glacial sand, with hummocky roughs and undulating fairways, with kettle depressions, kettle lakes, and other chaotic hazards. "If you want a golf course, go to a glacier" is the message according to Anita Harris. "Golf was invented on the moraines, the eskers, the pitted outwash plains--the glacial topography--of Scotland," she explained. "All over the world, when people make golf courses they are copying glacial landscapes. They are trying to make countryside that looks like this. I've seen bulldozers copying Scottish moraines in places like Louisiana. It's laughable."
On warm afternoons in summer, the meltwater rivers that pour from modern glaciers become ferocious and unfordable, like the Suiattle, in Washington, coming down from Glacier Peak, like the Yentna, in Alaska, falling in tumult from the McKinley massif. Off the big ice sheets of the Pleistocene have comemany hundreds of Suiattles and Yentnas, most of which are gone now, leaving their works behind. The rivers have built outwash plains beyond the glacial fronts, sorting and smoothing miscellaneous sizes of rock--moving cobbles farther than boulders, and gravels farther than cobbles, and sands farther than gravels, and silt grains farther than sands--then gradually losing power, and filling up interstices with groutings of clay. Enormous chunks of ice frequently broke off the retreating glaciers and were left behind. The rivers built around them containments of gravel and clay. Like big, buried Easter eggs, the ice sat there and slowly melted. When it was gone, depressions were left in the ground, pitting the outwash plains. The depressions have the shapes of kettles, or at least have been so described, and "kettle" is a term in geology. All kettles contained water for a time, and some contain water still. Rivers that developed under glaciers ran in sinuous grooves. Rocks and boulders coming out of the ice fell into the rivers, building thick beds contained between walls of ice. When the glacier was gone, the riverbeds were left as winding hills. The early Irish called them eskers, meaning pathways, because they used them as means of travel above detentive bogs. Where debris had been concentrated in glacial crevasses, melting ice left hillocks, monticles, hummocks, knolls, braes--collections of lumpy hills known generically to the Scots as kames. In Indiana as in Scotland--in La Bresse and Estonia as in NewEngland and Quebec--the sort of country left behind after all these features have been created is known as kame-and-kettle topography.
The interstate was waltzing with the glacier--now on the outwash plain, now on moraine, among the kettles and kames of Scottish Indiana. Roadcuts were green with vetch covering glacial till. We left 80 for a time, the closer to inspect the rough country. The glacier had been away from Indiana some twelve thousand years. There were many beds of dried-up lakes, filled with forest. In the Boundary Waters Area of northern Minnesota, the ice went back ten thousand years ago, possibly less, and most of the lakes it left behind are still there. The Boundary Waters Area is the scene of a contemporary conservation battle over the use and fate of the lakes. "Another five thousand years and there won't be much to fight about," Anita said, with a shrug and a smile. "Most of those Minnesota lakes will probably be as dry as these in Indiana." Some of the larger and deeper ones endure. We made our way around the shores of Lake James, Bingham Lake, Lake of the Woods, Loon Lake. Like Walden Pond, in Massachusetts, they were kettles.
The woods around them were bestrewn with boulders, each an alien, a few quite large. If a boulder rests above bedrock of another type, it has obviously been carried some distance and is known as an erratic. In Alaska, I have come upon glacialerratics as big as office buildings, with soil developing on their tops and trees growing out of them like hair. In Pokagon State Park, Indiana, handsome buildings looked out on Lake James--fieldstone structures, red and gray, made of Canadian rocks. The red jasper conglomerates were from the north shore of Lake Huron. The banded gray gneisses were from central Ontario. The sources of smaller items brought to Indiana by the ice sheets have been less easy to trace--for example, diamonds and gold. During the Great Depression, one way to survive in Indiana was to become a pick-and-shovel miner and earn as much as five dollars a day panning gold from glacial drift--as all glacial deposits, sorted and unsorted, are collectively called. There were no nuggets, nothing much heavier than a quarter of an ounce. But the drift could be fairly rich in fine gold. It had been scattered forth from virtually untraceable sources in eastern Canada. One of the oddities of the modern episodes of glaciation is that while three-fifths of all the ice in the world covered North America and extended south of Springfield, Illinois, the valley of the Yukon River in and near Alaska was never glaciated, and as a result the gold in the Yukon drainage--the gold of the richest placer streams ever discovered in the world--was left where it lay, and was not plucked up and similarly scattered by overriding ice. Miners in Indiana learned to look in their pans for menaccanite--beanlike pebbles of iron and titanium that signalled withsome consistency the propinquity of gold. The menaccanite had come out of the exposed Precambrian core of Canada--the Canadian craton, also known as the Canadian Shield. There were garnets in the gold pans, too--and magnetite, amphibole, corundum, jasper, kyanite. Nothing in that list is native to Indiana, and all are in the Canadian Shield. There is Canadian copper in the drift of Indiana, and there are diamonds that are evidently Canadian, too. Hundreds have been discovered--pink almondshaped hexoctahedrons, blue rhombic dodecahedrons. Weights have approached five carats, and while that is modest compared with twenty-carat diamonds found in Wisconsin, these Indiana diamonds have nonetheless been accorded the stature of individual appellations: the Young Diamond (1898), the Stanley Diamond (1900).
The source of a diamond is a kimberlite pipe --a relatively small hole bored through the crust of the earth by an expanding combination of carbon dioxide and water which rises from within the earth's mantle and moves so fast driving magma to the surface that it breaks into the atmosphere at supersonic speeds. Such events have occurred at random through the history of the earth, and a kimberlite pipe could explode under Moscow next year. Rising so rapidly and from so deep a source, a kimberlite pipe brings up exotic materials the like of which could never appear in the shallow slow explosion of a Mt. St. Helens or the flows of Mauna Loa. Amongthe materials are diamonds. Evidently, there are no diamond pipes, as they are also called, in or near Indiana. Like the huge red jasper boulders and the tiny flecks of gold, Indiana's diamonds are glacial erratics. They were transported from Canada, and by reading the fabric of the till and taking bearings from striations and grooves in the underlying rock --and by noting the compass orientation of drumlin hills, which look like sculptured whales and face in the direction from which their maker came--anybody can plainly see that the direction from which the ice arrived in this region was something extremely close to 045°, northeast. At least one pipe containing gem diamonds must exist somewhere near a line between Indianapolis and the Otish Mountains of Quebec, because the ice that covered Indiana did not come from Kimberley--it formed and grew and, like an opening flower, spread out from the Otish Mountains. With rock it carried and on rock it traversed, it narrated its own journey, but it did not reveal where it got the diamonds.
There is a layer in the mantle, averaging about sixty miles below the earth's surface, through which seismic tremors pass slowly. The softer the rock, the slower the tremor--so it is inferred that the lowvelocity zone, as it is called, is partly fluid. In the otherwise solid mantle, it is a level of lubricity upon which the plates of the earth can slide, interacting at their borders to produce the effects known as plate tectonics. The so-termed lithospheric plates, in otherwords, consist of crust and uppermost mantle and can be as much as ninety miles thick. Diamond pipes are believed to originate a good deal deeper than that--and in a manner which, as most geologists would put it, "is not well understood." After drawing fuel from surrounding mantle rock--compressed water from mica, in all likelihood, and carbon dioxide from other minerals--the material is thought to work slowly upward into the overlying plate. Slow it may be at the start, but a hundred and twenty miles later it comes out of the ground at Mach 2. The result is a modest crater, like a bullet hole between the eyes.
No one has ever drilled a hundred and twenty miles into the earth, or is likely to. Diamond pipes, meanwhile, have brought up samples of what is there. It is spewed all over the landscape, but it also remains stuck in the throat, like rich dense fruitcake. For the most part, it is peridotite, which is the lowest layer of the subcontinental package and is suspected to be the essence of the mantle. There is high-pressure recrystallized basalt, full of garnets and jade. There are olivine crystals of incomparable size. The whole of it is known as kimberlite, the matrix rock of diamonds.
The odds against diamonds appearing in any given pipe are about a hundred to one. Carbon will crystallize in its densest form only under conditions of considerable heat and pressure--pressures of the sort that exist deep below the thickest parts of theplates, pressures of at least a hundred thousand pounds per square inch. The thickest parts of the plates are the continental cores, the cratons. All diamond-bearing kimberlites ever found have been in pipes that came up through cratons. Down where diamonds form, they are stable, but as they travel upward they pass through regions of lower pressure, where they will swiftly turn into graphite. Only by passing through such regions at tremendous speed can diamonds reach the earth's surface as diamonds, where they cool suddenly and enter a state of precarious preservation that somehow betokens to human beings a touching sense of "forever." Diamonds shoot like bullets through the earth's crust. Nonetheless, they are often found within rinds of graphite. Countless quantities turn into graphite altogether or disappear into the air as carbon dioxide. At room temperature and surface pressure, diamonds are in repose on an extremely narrow thermodynamic shelf. They want to be graphite, and with a relatively modest boost of heat graphite is what they would become, if atmospheric oxygen did not incinerate them first. They are, in this sense, unstable--these finger-flashing symbols of the eternity of vows, yearning to become fresh pencil lead. Except for particles that are sometimes found in meteorites, diamonds present themselves in nature in no other way.
Kimberlite is easily eroded. A boy playing jacks in South Africa in 1867 picked up an alluvial diamond that led to the discovery of a number of pipes,one of which became the Kimberley Mine. From that pipe alone, fourteen million carats followed. The rock source of diamonds had never before been known. The Regent, the Koh-i-noor, the Great Mogul had been eroded out by streams. As the ice walls of the Pleistocene moved across Quebec, resculpting mountains, digging lakes, they apparently dozed through kimberlite pipes, scattering the contents southwest. The ice that plucked up the diamonds not only brought questions with it but also obscured the answers. How many pipes are there? Where are they? How rich are they in diamonds? If one tenmillionth of their content is gem diamond, they would be worth mining. They are somewhere northeast of Indiana. They are in all likelihood less than a quarter of a mile wide. They may be under glacial drift. They may be under lakes. A few have been discovered--none of value. Presumably, there are others, relatively studded with diamonds. Many people have searched. No one has found them.
"In Siberia, a few years ago, a couple of diamond pipes were located after diamonds were discovered in glacial drift," Anita told me.
I said, "Possibly some Russian geologists could be helpful here."
Looking out across the water of Lake James at a line of morainal hills, she chose to ignore the suggestion. The hills screened the outwash plain beyond. After some moments, she said, "Rocks remember. They may not be able to tell you exactly where inCanada to look for a diamond pipe, but when you have diamonds in this drift you'd better believe it is telling you that diamond pipes are there. Rocks are the record of events that took place at the time they formed. They are books. They have a different vocabulary, a different alphabet, but you learn how to read them. Igneous rocks tell you the temperature at which they changed from the molten to the solid state, and they tell you the date when that happened, and hence they give you a picture of the earth at that time, whether they formed three thousand million years ago or flowed out of the ground yesterday. In sedimentary rock, the colors, the grain sizes, the ripples, the crossbedding give you clues to the energy of the environment of deposition--for example, the force and direction and nature of the rivers that laid down the sediments. Tracks and trails left by organisms--and hard parts of their bodies, and flora in the rock--tell whether the material came together in the ocean or on the continent, and possibly the depth and temperature of the water, and the temperature on the land. Metamorphic rocks have been heated, compressed, and recrystallized. Their mineral composition tells you if they were originally igneous or sedimentary. Then they tell you what happened later on. They tell you the temperatures when they changed. At one point, I wanted to major in history. My teachers steered me into science, but I really majored in history. I grew up in topography like this, believe it or not. Looking atthese lakes and hills, you'd never think of Brooklyn. For that matter, you'd never think of Indiana. I didn't know what bedrock meant. I remember how amazed I was to discover, in learning to read rocks, how much history there was. All the glacial stuff arrived just yesterday and is sitting on the surface. Most of Brooklyn is a pitted outwash plain. Brooklyn means broken land."
A day would come when I would pick up Anita Harris at the home of a cousin of hers in Morganville, New Jersey, and drive across the Narrows Bridge to Brooklyn. She had not seen her neighborhood for twenty-five years. Her cousin, Murray Srebrenick, who gave us coffee before we left, was more than a little solicitous toward us, and even somewhat embarrassed, as if he were in the presence of people with an uncorrectable defect. He, too, had grown up in Brooklyn, and now, as an owner and operator of trucks, he supported his suburban life hauling clothes to Seventh Avenue. On runs through the city to various warehouses, he and his drivers knew what routes to avoid, but often enough they literally ran into trouble. Crime was part of his overhead, and as he rinsed the coffee cups he finally came out with what he was thinking and pronounced us insane. He spoke with animation, waving a pair of arms that could bring down game. Old neighborhoodor no old neighborhood, he said, he would not go near Williamsburg, or for that matter a good many other places in Brooklyn; and he reeled off stories of open carnage that might have tested the stomach of the television news. I wondered what it might be like to die defending myself with a geologist's rock hammer. Anita, for her part, seemed nervous as we left for the city. Twenty-five years away, she seemed afraid to go home.
It was an August day already hot at sunrise. "In Williamsburg, I lived at 381 Berry Street," she said as we crossed the big bridge. "It was the worst slum in the world, but the building did have indoor plumbing. Our first apartment there was a sixth-floor walkup. The building was from the turn of the century and was faced with red Triassic sandstone." Brooklyn was spread out before us, and Manhattan stood off to the north, with its two sets of skyscrapers three miles apart--the ecclesiastical spires of Wall Street, and beyond them the midtown massif. Anita asked me if I had ever wondered why there was a low saddle in the city between the stands of tall buildings.
I said I had always assumed that the skyline was shaped by human considerations--commercial, historical, ethnic. Who could imagine a Little Italy in a skyscraper, a linoleum warehouse up in the clouds?
The towers of midtown, as one might imagine, were emplaced in substantial rock, Anita said--rock that once had been heated near the point of melting,had recrystallized, had been heated again, had recrystallized, and, while not particularly competent, was more than adequate to hold up those buildings. Most important, it was right at the surface. You could see it, in all its micaceous glitter, shining like silver in the outcrops of Central Park. Four hundred and fifty million years in age, it was called Manhattan schist. All through midtown, it was at or near the surface, but in the region south of Thirtieth Street it began to fall away, and at Washington Square it descended abruptly. The whole saddle between midtown and Wall Street would be underwater, were it not filled with many tens of fathoms of glacial till. So there sat Greenwich Village, SoHo, Chinatown, on material that could not hold up a great deal more than a golf tee--on the ground-up wreckage of the Ramapos, on crushed Catskill, on odd bits of Nyack and Tenafly. In the Wall Street area, the bedrock does not return to the surface, but it comes within forty feet and is accessible for the footings of the tallest things in town. New York grew high on the advantage of its hard rock, and, New York being what it is, cities all over the world have attempted to resemble New York, in much the way that golf courses all around the world have attempted to resemble St. Andrews. The skyline of nuclear Houston, for example, is a simulacrum of Manhattan's. Houston rests on twelve thousand feet of montmorillonitic clay, a substance that, when moist, turns into mobile jelly. After taking so much money out of the ground,the oil companies of Houston have put hundreds of millions back in. Houston is the world's foremost city in fat basements. Its tall buildings are magnified duckpins, bobbing in their own mire.
We skirted Brooklyn on the Belt Parkway, heading first for Coney Island, where Anita had spent many a day as a child, and where, somewhat impatiently, she had been born. Her mother, seven months pregnant, took a subway to the beach one day, and Anita first drew breath in Coney Island Hospital.
"Cropsey Avenue," she said now, reading a sign. "Keep right, we're going off here."
I went into the right lane, signals blinking, but the exit was chocked with halted traffic. There were police. There were flashing lights. Against the side of an abused Pontiac, an evidently unruly young man was leaning palms flat, like a runner stretching, while a cop addressed him with a drawn pistol. "Welcome home, Anita," said Anita.
The broad beach was silent, so early in the morning, where people in ten thousands had been the day before, and where numbers just as great would soon return. The Parachute Jump stood high in relief. The Cyclone was in shadow and touched by slanting light. Reminiscently, Anita ran her eye from the one to the other and to the elevated railways beyond. When a fossil impression is left in sand by the outside of an organic structure, it is known in geology as an external mold. One would not have tobe a sedimentologist to read this beach, with its colonies of giant bivalves. We walked to the strandline, the edge of the water, where the play of waves had concentrated heavy dark sands--hematite, magnetite, small garnets broken out by the glacier from their matrix of Manhattan schist.
The beach itself, with its erratic sands, was the extremity of the outwash plain. The Wisconsinan ice sheet, arriving from the north, had come over the city not from New England, as one might guess, but primarily from New Jersey, whose Hudson River counties lie due north of Manhattan. Big boulders from the New Jersey Palisades are strewn about in Central Park, and more of the same diabase is scattered through Brooklyn. The ice wholly covered the Bronx and Manhattan, and its broad snout moved across Astoria, Maspeth, Williamsburg, and Bedford-Stuyvesant before sliding to a stop in Flatbush. Flatbush was the end of the line, the point of return for the "Ice Age," the locus of the terminal moraine. Water poured in white tumult from the melting ice, carrying and sorting its freight of sands and gravels, building the outwash plain: Bensonhurst, Canarsie, the Flatlands, Coney Island. When Anita was a child, she would ride the D train out to Coney Island, with an old window screen leaning against her knees. She sifted the beach sand for lost jewelry. In the beach sand now, she saw tens of thousands of garnets. There is a lot of iron in the Coney Island beach as well, which makes it tawny from oxidation,and not a lot of quartz, which would make it white. The straw-colored sand sparkled with black and silver micas--biotite, muscovite--from Fifth Avenue or thereabouts, broken out of Manhattan schist. A beach represents the rock it came from. Most of Coney Island is New Jersey diabase, Fordham gneiss, Inwood marble, Manhattan schist. Anita picked up some sand and looked at it through a hand lens. The individual grains are characteristically angular and sharp, she said, because the source rock was so recently crushed by the glacier. To make a well-rounded grain, you need a lot more time. Weather and waves had been working on this sand for fifteen thousand years.
If the gneissic grains and garnets were erratics, so in their way were the Schenley bottles, the Pepsi-Cola cans, the Manhattan Schlitz, the sand-coated pickles and used paper plates.
"Colonial as penguins, dirtier than mud daubers," I observed of the creatures of the beach.
"We rank with bats, starlings, and Pleistocene sloths as the great messmakers of the world," said Anita, and we left Coney Island for Williamsburg.
North over the outwash plain we followed Ocean Parkway five miles--broad, tree-lined Ocean Parkway, with neat houses in trim neighborhoods, reaching into shaded streets. Ahead, all the while, loomed the terminal moraine, suggesting, from a distance, an escarpment, but actually just a fairly steep hill. Eastern Parkway defines its summit, two hundred feethigh. Two hundred feet of till. Near Prospect Park you begin to climb. One moment you are level on the plain and the next you are nose up, gaining altitude. There are cemeteries in every direction: Evergreens Cemetery, Lutheran Cemetery, Mt. Carmel, Cypress Hills, Greenwood Cemetery--some of the great necropolises of all time, with three million under sod, moved into the ultimate neighborhood, the terminal moraine. "In glacial country, all you have to do is look for cemeteries if you want to find the moraine," Anita said. "A moraine is poor farmland--steep and hummocky, with erratics and boulders. Yet it's easy ground to dig in, and well drained. An outwash plain is boggy. There's a cemetery over near Utica Avenue that's in the outwash. Most people prefer moraine. I would say it's kind of distasteful to put your mother down into a swamp."
Ebbets Field, where they buried the old Brooklyn Dodgers, was also on the terminal moraine. When a long-ball hitter hit a long ball, it would land on Bedford Avenue and bounce down the morainal front to roll toward Coney on the outwash plain. No one in Los Angeles would ever hit a homer like that.
We detoured through Prospect Park, which is nestled into the morainal front and is studded with big erratics on raucously irregular ground. It looks much like Pokagon Park, in Indiana, with the difference that the erratics there are from the Canadian Shieldand these were from the New Jersey Palisades. Pieces of the Adirondacks have been found in Pennsylvania, pieces of Sweden on the north German plains, and no doubt there is Ticonderoga dolomite, Schenectady sandstone, and Peekskill granite in the gravels of Canarsie and the sands of Coney Island. But such distant transport, while it characterizes continental ice sheets wherever they have moved, accounts for a low percentage of the rock in glacial drift. The glacier cuts and fills. Continuously, it plucks up material and sets it down, plucks it up, sets it down. It taketh away, and then it giveth. A diamond may travel from Quebec to Indiana, some dolomite from Lake George to the sea, but most of what is lifted is dropped nearby--boulders from New Jersey in Prospect Park.
"Glacial geology is simple to deal with," Anita said, "because so much of what the glacier created is preserved. Also, you can go places and see the same processes working. You can go to Antarctica and see continental glaciation. There's alpine glaciation in Alaska."
This warm clear summer day was now approaching noon, and Prospect Park was quiet and unpeopled. It was all but deserted. Anita as a child had come here often. She remembered people and picnics everywhere she looked, none of this ominous silence. "I suppose it isn't safe," she said, and we moved on toward Williamsburg.
As we drew close, she became even more obviously nervous. "They tell me it's just the worst slum in the world now," she said. "I don't know if I should tell you to roll up all the windows and lock the doors."
"We would die of the heat."
"This is a completely unnatural place," she went on. "It's a totally artificial environment. Cockroaches, rats, human beings, and pigeons are all that survive. At Brooklyn College, my instructors had difficulty relating geology to the lives of people in this artificial world. In the winter, maybe you froze your ass off waiting for the subway. Maybe that was a way to begin discussing glaciation. In the city, let me tell you, no one knows from geology."
We went first to her high school. It appeared to be abandoned and was not. It was a besooted fortress with battlements. Inside were tall cool hallways that smelled of polish and belied the forbidding exterior. She had walked the halls four years with A's on her report cards and been graduated with high distinction at the age of fifteen. We went to P.S. 37, her grade school. It was taller than wide and looked like an old brick church. It was abandoned, beyond a doubt--glassless and crumbling. Trees of heaven, rooted in the classroom floors, were growing out the windows. Anita said, "At least I'm glad I saw my school, I think, before they take it away."
We came to Broadway and Berry Street, and now she had before her for the first time in twenty-fiveyears the old building where she had lived. It was a six-story cubical tenement, with so many fire escapes that it seemed to be faced more with iron than with the red Triassic stone. Anita looked at the building in silence. Usually quick to fill the air with words, she said nothing for long moments. Then she said, "It doesn't look as bad as it did when I lived here."
She stared on at the building for a while before speaking again, and when she did speak the nervousness of the morning was completely gone from her voice. "It's been sandblasted," she said. "They've cleaned it up. They've put a new facing on the lower stories, and they've sandblasted the whole building. People are wrong. They're wrong in what they tell me. This place looks cleaner than when I lived here. The whole neighborhood still looks all right. It hasn't changed. I used to play stickball here in the street. This is my neighborhood. This is the same old neighborhood I grew up in. I'm not afraid of this. I'm getting my confidence up. I'm not afraid."
We moved along slowly from one block to another. A young woman crossed the street in front of us, pushing a baby carriage. "She's wearing a wig, I promise you," Anita said. "Her head may be shaved." Singling out another woman among the heterogeneous people of the neighborhood, she said, "Look. See that woman with the turban? She has her hair covered on purpose. They're Chassidic Jews. Their hair is shaved off or concealed so they will not be attractiveto passing men." There was a passing man with long curls hanging down either side of his head--in compliance with a dictum of the Pentateuch. "Just to be in the streets here is like stepping into the Middle Ages," Anita said. "Fortunately, my parents were not religious. I would have thought these people would have moved out of here long ago. Chassidic Jews are not all poor, I promise you. Their houses may not look like much, but you should see them inside. They're diamond-cutters. They handle money. And they're still here. People are wrong. They are wrong in what they have told me."
We went out of the noon sun into deep shade under the Williamsburg Bridge, whose immense stone piers and vaulting arches seemed Egyptian. She had played handball under there when she was a girl. "There were no tennis courts in this part of the world, let me tell you." When the boys went off to swim in the river, she went back to Berry Street. "Me? In the river? Not me. The boys swam nude."
In the worst parts of summer, when the air was heavy and the streets were soft, Anita went up onto the bridge, climbing to a high point over the river, where there was always a breeze. Seven, eight years old, she sat on the pedestrian walk, with her feet dangling, and looked down into the Brooklyn Navy Yard. The Second World War was in full momentum. U.S.S. Missouri, U.S.S. Bennington, U.S.S. Kearsarge --she saw keels going down and watched battleships and carriers grow. It was a remarkable form of entertainment,but static. Increasingly, she wondered what lay beyond the bridge. One day, she got up the courage to walk all the way across. She set foot on Manhattan and immediately retreated. "I wanted to go up Delancey Street, but I was too scared."
Next time, she went up Delancey Street three blocks before she turned around and hurried home. In this manner, through time, she expanded her horizons. In the main, she just looked, but sometimes she had a little money and went into Manhattan stores. About the only money she ever had she earned returning bottles for neighbors, who gave her a percentage of the deposit. Her idea of exceptional affluence was a family that could afford fresh flowers. Her mother was a secretary whose income covered a great deal less than the family's needs. Her father was a trucker ("with a scar on his face that would make you think twice"), and his back had been broken in an accident. He would spend three years in traction, earning nothing. Gradually, Anita's expeditions on foot into Manhattan increased in length until she was covering, round trip, as much as twelve miles. Her line of maximum advance was somewhere in Central Park. "That's as far as I ever got. I was too scared." Going up the Bowery and through the East Village, she had no more sense of the geology than did the men who were lying in the doorways. When she looked up at the Empire State Building, she was unaware that it owed its elevation to the formation that outcropped in Central Park; and when she sawthe outcrops there, she did not wonder why, in the moist atmosphere of the American East, those great bare shelves of sparkling rock were not covered with soil and vegetation. In Wyoming, wind might have stripped them bare, but Wyoming is miles high and drier than the oceans of the moon. Here in the East, a river could wash rock clean, but this rock was on the high ground of an island, far above flood and tide. She never thought to wonder why the rock was scratched and grooved, and elsewhere polished like the foyer of a bank. She didn't know from geology.
In Brooklyn College, from age fifteen onward, she read physics, mineralogy, structural geology, igneous and metamorphic petrology. She took extra courses to the extent permitted. To attend the college she had to pay six dollars a semester, and she meant to get everything out of the investment she could. There were also lab fees and breakage fees. Breakage fees, in geology, were not a great problem. Among undergraduate colleges in the United States, this one was relatively small, about the size of Harvard, which it resembled, with its brick-and-white-trim sedate Colonial buildings, its symmetrical courtyards and enclosed lawns; and like Harvard it stood on outwash. Brooklyn College is in south Flatbush, seaward of the terminal moraine. When Anita was there, in the middle nineteen-fifties, there were so many leftists present that the college was known as the Little Red Schoolhouse. She did not know from politics, either. She was in a world of roof pendantsand discordant batholiths, elastic collisions and neutron scatteration, and she branched out into mineral deposits, field mapping, geophysics, and historical geology, adding such things to the skills she had established earlier in accounting, bookkeeping, typing, and shorthand. It had been assumed in her family that she would be a secretary, like her mother.
Now when she goes up Fifth Avenue--as she did with me that summer day--she addresses Fifth Avenue as the axis of the trough of a syncline. She knows what is underfoot. She is aware of the structure of the island. The structure of Manhattan is one of those paradoxes in spatial relations which give geologists especial delight and are about as intelligible to everyone else as punch lines delivered in Latin. There is a passage in the œuvre of William F. Buckley, Jr., in which he remarks that no writer in the history of the world has ever successfully made clear to the layman the principles of celestial navigation. Then Buckley announces that celestial navigation is dead simple, and that he will pause in the development of his present narrative to redress forever the failure of the literary class to elucidate this abecedarian technology. There and then--and with intrepid, awesome courage--he begins his explication; and before he is through, the oceans are in orbit, their barren shoals are bright with shipwrecked stars. With that preamble, I wish to announce that I am about to make perfectly clear howFifth Avenue, which runs along the high middle of a loaf of rock that lies between two rivers, runs also up the center of the trough of a syncline. When rock is compressed and folded (like linen pushed together on a table), the folds are anticlines and synclines. They are much like the components of the letter S. Roll an S forward on its nose and you have to the left a syncline and to the right an anticline. Each is a part of the other. Such configurations in rock compose the structure of a region, but will not necessarily shape the surface of the land. Erosion is the principal agent that shapes the surface of the land; and erosion--particularly when it packs the violence of a moving glacier--can cut through structure as it pleases. A carrot sliced the long way and set flat side up is composed of a synclinal fold. Manhattan, embarrassingly referred to as the Big Apple, might at least instructively be called the Big Carrot. River to river, erosion has worn down the sides, and given the island its superficial camber. Fifth Avenue, up on the high ground, is running up the center of a synclinal trough.
On the upper West Side that afternoon, Anita drew her rock hammer and relieved Manhattan of some dolomite marble, which she took from an outcrop for its relevance to her research in conodonts. She found the marble "overcooked." She said, "To get that kind of temperature, you have to go down thirty or forty thousand feet, or have molten rock nearby, or have a high thermal gradient, which canvary from place to place on earth by a factor of four. This marble is so cooked it is almost volatilized. This --you better believe--is hot rock." At Seventysecond Street and West End Avenue, she stopped to admire a small apartment building whose façade, in mottled greens and black, was elegant with serpentine. On Sixty-eighth Street between Fifth and Madison, she was impressed by a house of gabbro, as anyone would be who had spent a childhood emplaced like a fossil in Triassic sand. It was a house of great wealth, the house of gabbro. Up the block was a house of granite, even grander than the gabbro, and beyond that was a limestone mansion so airily patrician one feared it might dissolve in rain. Anita dropped acid on it and watched it foam.
Jack Epstein, Anita's northern-Appalachian geologist, went to Brooklyn College, too, and subsequently enrolled in the master's program at the University of Wyoming. Anita tried to follow, in 1957, but the geology department in Laramie offered no fellowships for first-year graduate students. ("I needed money. I didn't have a pot to cook in.") She looked into places like Princeton, with geology departments outstanding in the world, but they were even less receptive than Wyoming. In those days, Princeton would not have admitted a woman had she been a direct descendant of Sir Charles Lyell offeringas tuition her weight in gems. Anita applied to ten schools in all. The best offer came from Indiana University, in Bloomington, where her professors were soon much aware of her as an extremely bright and aggressive student with the disconcerting habit of shaking her head while they talked, as if to say no, no, no, no, you cratonic schnook, you don't know from nothing. Something of the sort was not always far from her thoughts. ("I am not a very orthodox geologist. I do buy some dogma, if I think it's common sense.")
Bloomington stood upon Salem limestone, which, in the terminology of the building trade, makes beautiful "dimension stone," and is cut to be the cladding of cities. It formed from lime mud in the Meramecian age of late Mississippian time--between 332 and 327 million years before the present --when Bloomington was at the bottom of a shallow arm of the transgressing ocean, an epicratonic sea. "You people in New York may have your Empire State Building," a professor pointed out to Anita. "But out here we have the hole in the ground it came from."
Anita and Jack Epstein were married in 1958, and, with their newly acquired master's degrees, went to work for the United States Geological Survey. Within the profession, the Survey had particular prestige. A geologist who sought field experience was likely to obtain it in such quantity and variety nowhere else. Anita and Jack Epstein looked upongeology as "an extremely applied science" and shared a conviction that field experience was indispensable in any geological career--no less essential to a modern professor than it ever was to a pick-and-shovel prospector. ("People should go out and get experience and not just turn around and teach what they've been taught.") In their first year in the Survey--to an extent beyond anything they could ever have guessed--they would get what they sought.
Because geology is sometimes intuitive even to the point of being subjective, the sort of field experience one happens to acquire may tend to influence one's posture with regard to deep questions in the science. Geologists who grow up with young rocks are likely to subscribe strongly to the doctrine of uniformitarianism, whereby the present is seen to be the key to the past. They discern a river sandbar in a wall of young rock; they see a sandbar in a living river; and they know that each is in the process of becoming the other, cyclically through time. Whatever is also was, and ever again shall be. Geologists who grow up with very old rock tend to be impressed by the fact that it has been around since before the earliest development of life, and to imagine a progression in which the recycling of the earth's materials is a subplot in a dramatic story that begins with dark scums in motion on an otherwise featureless globe and evolves through various continental configurations toward the scenery of the earth today.They refer to the earliest part of that story as "scum tectonics." The rock cycle--with its crumbling mountains being carried to the sea to form there the rock of mountains to be--is the essence of the uniformitarian principle, which was first articulated by James Hutton, of Edinburgh, at the end of the eighteenth century, marking the beginning of modern geological insight and the decline of the theological notion that the earth is a few thousand years old and that man has been a participant in its history almost from the beginning. Radiometrics and any number of other cross-checking measurements of time now tell us that the earth existed about forty-six hundred million years before the beginning of the Judeo-Christian era, thereby recasting mankind as an arriviste species, an obviously unsettled obtruder.
Before Hutton, geology was seen as a succession of catastrophes--most notably Noah's Flood, which not only had placed oysters, clams, and other marine fossils in mountain rock but had sculpted most of the features of the modern earth. All else was "antediluvian." The world had been shaped by brief, cataclysmic events. Hutton, with his depths of time --his vision of great crustal changes occurring slowly through unguessable numbers of years--opened the way to Darwin (time is the first requirement of evolution) and also placed emphasis on repetitive processes and a sense that change is largely gradual. In contemporary dress, these concepts are still at odds in geology. Some geologists seem to look upon therock record as a frieze of catastrophes interspersed with gaps, while others prefer to regard everything from rockslides and volcanic eruptions to rifted continents and plate collisions as dramatic passages in a quietly unfolding story. If you grow up in Brooklyn, you are free to form your prejudices where you may.
Anita Epstein's sense of the dynamics of the earth underwent considerable adjustment one night in 1959, when she and her husband were on summer field assignment in southwestern Montana. They were there to do geologic mapping and studies in structure and stratigraphy in the Madison Range and the Gallatin Range, where Montana is wrapped around a corner of Yellowstone Park. They lived in a U.S.G.S. house trailer in a grove of aspens on the Blarneystone Ranch, a lovely piece of terrain whose absent owner was Emmett J. Culligan, the softener of water. Since joining the Survey, they had worked in Pennsylvania, mapping quadrangles in the region of the Delaware Water Gap, and had spent the winter at headquarters in Washington, and now they were being given a chance to see some geology in a part of the United States where it is particularly visible--in Anita's words, "where it all hangs out."
The ranch was close by Hebgen Lake, which owed itself to a dam in the valley of the Madison River. The valley ran along the line of a fault that was thought to be inactive until that night. The air was crisp. The moon was full. The day before, a fire watcher in a tower in the Gallatins had becomeaware of an unnerving silence. The birds were gone, he realized. Birds of every sort had made a wholesale departure from his mountain. It would be noted by others that bears had taken off as well, while bears that remained walked preoccupied in circles. The Epsteins had no knowledge of these signs and would not have known what to make of them if they had. They were unaware then that Chinese geologists routinely watch wildlife for intimations of earthquakes. They were also unaware that David Love, of the Survey's office in Laramie, had published an abstract only weeks before called "Quaternary Faulting in and near Yellowstone Park," in which he expressed disagreement with the conventional wisdom that seismic activity on a grand scale was a thing of the past in that region. He said he thought a major shock was not unlikely. Anita was shuffling cards, 11:37 P.M., when the lantern above her began to swing, crockery fell from cabinets, and water leaped out of a basin. Jack tried to catch the swinging lantern and "it beaned him on the head." The floor of the trailer was moving in a way that reminded her of the Fun House at Coney Island. They ran outside. "Trees were toppling over. The solid earth was like a glop of jelly," she would recall later. In the moonlight, she saw soil moving like ocean waves, and for all her professed terror she was collected enough to notice that the waves were not propagating well and were cracking at their crests. She remembers something like thirty seconds of "tremendous explosive noise,"an "amplified tornado." She was close to the epicenter of a shock that was felt three hundred and fifty miles away and markedly affected water wells in Hawaii and Alaska. East and west from where she stood ran an eighteen-mile rip in the surface of the earth. The fault ran straight through Culligan's ranch house, and had split its levels, raising the back twelve feet. The tornado sound had been made by eighty million tons of Precambrian mountainside, whose planes of schistosity had happened to be inclined toward the Madison River, with the result that half the mountain came falling down in one of the largest rapid landslides produced by an earthquake in North America in historical time. People were camped under it and near it. Among the dead were some who died of the air blast, after flapping like flags as they clung to trees. Automobiles rolled overland like tumbleweed. They were inundated as the river pooled up against the rockslide, and they are still at the bottom of Earthquake Lake, as it is called--a hundred and eighty feet deep.
The fault offset the water table, and the consequent release of artesian pressure sent grotesque fountains of water, sand, and gravel spurting into the air. Yet the dam at Hebgen Lake held--possibly because the lake's entire basin subsided, in places as much as twenty-two feet. Seiche waves crossed its receding surface. A seiche is a freshwater tsunami, an oscillation in a bathtub. The surface of Hebgen Lake was aslosh with them for twelve hours, but thefirst three or four were the large ones. Entering lakeside bungalows, they drowned people in their beds.
When a volcano lets fly or an earthquake brings down a mountainside, people look upon the event with surprise and report it to each other as news. People, in their whole history, have seen comparatively few such events; and only in the past couple of hundred years have they begun to sense the patterns the events represent. Human time, regarded in the perspective of geologic time, is much too thin to be discerned--the mark invisible at the end of a ruler. If geologic time could somehow be seen in the perspective of human time, on the other hand, sea level would be rising and falling hundreds of feet, ice would come pouring over continents and as quickly go away. Yucatáns and Floridas would be under the sun one moment and underwater the next, oceans would swing open like doors, mountains would grow like clouds and come down like melting sherbet, continents would crawl like amoebae, rivers would arrive and disappear like rainstreaks down an umbrella, lakes would go away like puddles after rain, and volcanoes would light the earth as if it were a garden full of fireflies. At the end of the program, man shows up--his ticket in his hand. Almost at once, he conceives of private property, dimension stone, and life insurance. When a Mt. St. Helens assaults his sensibilities with an ash cloud eleven miles high, he writes a letter to the New York Times recommending that the mountain be bombed.
As the night returned to quiet and the groundceased to move, Anita recovered whatever composure she had lost, picked up her deck of cards, and said to herself, "That's the way it goes, folks. The earth's a very shaky mobile thing, and that's how it works. Apparently, the mountains around here are still going up." Later, she would say, "We were taught all wrong. We were taught that changes on the face of the earth come in a slow steady march. But that isn't what happens. The slow steady march of geologic time is punctuated with catastrophes. And what we see in the geologic record are the catastrophes. Look at a graded sandstone and see the bedding go from fine to coarse. That's a storm. That's one storm--when the water came up and laid the coarse material down over the fine. In the rock record, the tranquillity of time is not well represented. Instead, you have the catastrophes. In the Southwest, they live from one catastrophe to another, from one flash flood to the next. The evolution of the world does not happen a grain at a time. It happens in the hundred-year storm, the hundred-year flood. Those things do it all. That earthquake made a catastrophist of me."
No one knew where the bears went when they left the Gallatin Range. When they came back, they were covered with mud.
Catastrophism in another form presented itself that autumn when Jack Epstein was transferred tothe office of the Geological Survey's Water Resources Division in Alexandria, Louisiana. There was no position for Anita, and she could not have had a job even if one had been open, for it was a rule of the Survey that spouses could not work for the same supervisor. The Alexandria office was small, and included one supervisor. Her nascent geological career was suddenly aborted. She taught physics and chemistry in a Rapides Parish high school. In the summer that followed, she worked for the state government as an interviewer in the unemployment office. She did her geology when and where she could. Driving home from work, she saw people dressed like signal flags hitting golf balls on fake moraines.
Fortunately, her husband was even less interested in the water resources of Louisiana than she was in the unemployment interviews. They decided they needed Ph.D.s to improve their chances of working somewhere else. They enrolled at Ohio State, and in eastern Pennsylvania took up the summer fieldwork that led to their dissertations. They did geologic mapping and biostratigraphy among the ridges of the folded Appalachians--noting the directional trends of the various formations (the strike) and their angles of dip, along a narrow band of deformation from the Schuylkill Gap near Reading to the Delaware Water Gap, and on toward the elbow of the Delaware River where Pennsylvania, New Jersey, and New York conjoin. The most recent ice sheet had reached the Water Gap--where the downcuttingDelaware River had sawed a mountain in two--and had filled the gap, and even overtopped the mountain, and then had stopped advancing. So the country of their dissertations was filled with fossil tundra, with kames and eskers, with periglacial boulders and the beds of vanished lakes, with erratics from the Adirondacks, with a vast imposition of terminal moraine. Like the outwash of Brooklyn and the tills of Indiana, this Pennsylvania countryside helped to give Anita her sophistication in glacial geology, which was consolidated at Ohio State, whose Institute of Polar Studies trains specialists in the field. Glacial evidence was not, however, what drew her particular attention. The Wisconsinan ice was modern, in the long roll of time, in much the way that Edward VII is modern compared with a hominid skull. The ice melted back out of the Water Gap seventeen thousand years ago. Anita was more interested in certain stratigraphic sequences in rock that protruded through the glacial debris and had existed for several hundred million years. She would crush this rock, separate out certain of its components, and under a microscope at fifty to a hundred magnifications study its contained conodonts, hard fragments of the bodies of unknown marine creatures--hard as human teeth, and of the same material. At a hundred magnifications, some of them looked like wolf jaws, others like shark teeth, arrowheads, bits of serrated lizard spine--not unpleasing to the eye, with an asymmetrical, objet-trouve appeal.Many of them resembled conical incisors, and in 1856 this had caused a Latvian paleontologist to give them their name. Conodonts were in many formations but were most easily extracted from carbonate rocks (limestone and dolomite). They would become useful to geologists because they were all over the earth, and because the creatures that left them behind had appeared in the world near the beginning of the Paleozoic era and had vanished forever soon after its end. Yet not until the late nineteen-fifties did studies begin to be published that brought conodonts to prominence as index fossils, helping to subdivide a specific zone of time, about one-thirteenth of the history of the earth, running from 560 to 195 million years before the present. As the conodont-bearing creatures evolved through those years, their conodonts became increasingly complex, with apparatus extending in denticles, bars, and blades. Geologists, observing these changes, could readily assign relative ages to the places where conodonts were found.
After collecting her samples, Anita could not have been shipping them back to a better place than Ohio State. Just as Johns Hopkins has been celebrated for lacrosse, Hartwick for soccer, and Rollins for tennis, Ohio State is known for conodonts. Geologists call Ohio State "a conodont factory." Like all the other workers there (a specialist in the field is known in the profession as "a conodont worker"), she noticed incidentally as she catalogued the evolutionarychanges in her specimens that some were light and some were dark. They were white, brown, yellow, tan, and gray. Since they were coming into Columbus from all over the United States, and in fact the world, she began to notice that in a general way their colors followed geographical patterns. She wondered what that might suggest. She looked at conodonts from Kentucky and Ohio, which were of a yellow so pale it was almost white. From western Pennsylvania they were jonquil, from central Pennsylvania brown. The ones she had collected north of Schuylkill Gap were black. She thought at first there was something wrong with her samples, but her adviser told her that in all likelihood the blackness was merely the result of pressures attendant when the limestone or dolomite was being deformed. He did not encourage her to make a formal study of the matter, and she returned to her absorptions with conodont biostratigraphy. On one of her trips East, she crossed New York State, collecting dolomite and limestone all the way. From Lake Erie to the Catskills, New York State is a cake of Devonian rock, lying flat in a swath sixty miles wide. You can travel across it chipping off rock of the same approximate age, and not just any old Devonian samples--for the Devonian period covers fifty million years--but, say, limestone and dolomite from the Gedinnian age, which is eight million years of early Devonian, or even from the Helderbergian stage of middle Gedinnian time. For as much as a hundred and fifty miles,you could follow a line of time no broader than three million years. You could cut it that fine. Anita did something of the sort, and crushed the rocks at Ohio State. She noticed that the conodonts were amber in Erie County, tan in Schuyler and Steuben. They were cordovan in Tioga and Broome. In Albany County, they were dark as pitch.
She wondered what the colors might be suggesting about the geologic history of the region.
Nothing much, her adviser assured her. The colors were the results of tectonic pressures.
It had been just a passing thought. She let it go, and went back to work on her thesis, which would be titled "Stratigraphy and Conodont Paleontology of Upper Silurian and Lower Devonian Rocks of New Jersey, Southeastern New York, and Eastern Pennsylvania." She was documenting subtle evolutionary differences in conodonts close to the Silurian-Devonian boundary, a point in time just under four hundred million years ago. And, arranging her microfossils in chronicle form, she was differentiating and cataloguing in time the units of rock from which they had been removed. This in turn would help her to understand the structure of the country in which she had picked up the rock. Conodont colors faded in her mind.
By 1966, having completed their course work at Ohio State, Anita and Jack Epstein had returned to work for the Geological Survey--he to concentrate on northern-Appalachian geology and she to takewhat she could get, which was a map-editing job in Washington. She would have preferred to work on conodonts, but the federal budget at that time covered only one conodont worker, and someone else had the job. Before long, she had become general editor of all geologic mapping taking place east of the Mississippi River. She dealt with hundreds of geologists. There were fifteen hundred in the Survey, and the quality of their work, their capacity for visualizing plunging synclines and recumbent folds, tended to vary. She looked upon some of them as "losers." Such people were sent to what she privately described as "penal quadrangles": the lesser bayous of Louisiana, the Okefenokee Swamp. If they did not know strike from dip, they could go where they would encounter neither. She did not feel pity. Better to be a loser in the United States, she thought, than to be a geological peasant in China. There are four hundred thousand people in the Chinese geological survey. "It's a hell of an outfit," in Anita's words. "If they want to see exposed rock, they don't depend on streambanks and roadcuts, as we do. If an important Chinese geologist wants to see a section of rock, the peasants dig out a mountainside."
She was a map editor for seven years, during all of which she continued her conodont research, almost wholly on her own time. Collecting rock from Maryland and Pennsylvania, she crushed it and "ran the samples" at home. Running samples was not just a matter of pushing slides past the nose of a microscope.After pulverizing the rock and dissolving most of it in acid, she had to sort its remaining components, and this could not be done chemically, so it had to be done physically. It was a problem analogous to the separation of uranium isotopes, which in the early nineteen-forties had brought any number of physicists to a halt. It was also something like sluicing gold, but you could not see the gold.
Anita uses tetrabromoethane, an extremely heavy and extremely toxic fluid that costs a hundred and fifty dollars a gallon. Granite will float in tetrabromoethane. Quartz will float in tetrabromoethane. Conodonts sink without a bubble. Her hands in rubber gloves within a chemical hood, she pours the undissolved rock residue into the tetrabromoethane. The lighter materials float--limestone, dolomite, quartz. Inconveniently, conodonts are not all that sink in tetrabromoethane. Pyrite, among other things, sinks, too. With methylene iodide, a fluid even heavier than tetrabromoethane, she turns the process around. In methylene iodide, the pyrite and whatnot go to the bottom, while the conodonts, among other things, float. Electromagnetically, she further concentrates the conodonts. She can now have a look at them under a microscope, seeing "bizarre shapes that any idiot can recognize," and assign them variously to the Anisian, Ladinian, Cayugan, Osagean, Llandoverian, Ashgillian, or any other among tens of dozens of subdivisions of Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, and Triassic time.
While recording ages, she could not ignore colors, and the question of their possible significance returned to her mind. In the Appalachians generally, formations thickened eastward. The farther east you went, the deeper the rock had once been buried--the greater the heat had once been. Heat appeared to her to have affected the color of the conodonts in the same manner that it affects the color of butter--turning it from yellow to light brown to darker brown to black-and-ruined smoking in the pan. Oh, she thought. You could use those things as thermometers. They might help in mapping metamorphic rock. Metamorphism, the process by which heat and pressure change one kind of rock into another--turn shale into slate, turn granite into gneiss, turn limestone into marble--is divided into grades of intensity. Maybe conodont colors, plotted on a map, could demonstrate the shadings of the grades. At work, she began saying to people, "Show me a conodont and I'll tell you where in the Appalachians it came from." With amazing accuracy she repeatedly passed the test. She imagined that color had been controlled by carbon fixing. In the presence of heat, she thought, the amount of carbon in a given conodont would have remained constant while the amounts of hydrogen and oxygen declined, which is what happens in heated butter. No one seemed to agree with her. One way to test her idea might have been to scan for individual elements with an electron probe, but this was 1967 and electron probes in those days could not pick up light elements like hydrogenand oxygen. She sought other avenues of proof--with other types of equipment that no one has at home. The Geological Survey had a question for her, however. They said, "Who needs to know this anyway?" The Survey had been established to serve the public.
"O.K., to hell with it," Anita told herself. Half a dozen years went by. With the oil embargo of 1973, the Survey felt a need to do everything possible to effect an increase in the nation's energy resources. Its Branch of Oil & Gas Resources was expanded fifteenfold. There were new positions for about two hundred front-rank geologists. They were hired away from oil companies or brought in from elsewhere in the Survey. What attracted the people from the companies was the opportunity to do publishable research. To run the branch, Peter R. Rose gave up his position as a staff geologist of Shell. Leonard Harris, of the Survey, a southern-Appalachian geologist whose interests had moved northward from the Ozarks, came into the Oil & Gas Branch, too. One day, he mentioned to Anita that he understood she was interested in conodonts. He said he would like to have some of her rock samples analyzed for "organic maturation."
She listened to this dark-haired soft-spoken blueeyed geologist as if he had come from a place a great deal more distant than the Ozarks. Just how did he propose to discern organic maturation? "Do you do that chemically? ' she asked him.
"Yes," he said. "You can. And you can also do it by observing changes in organic materials such as fossil pollen and spores, where they exist."
"How do you do that?" she said.
"By looking at color change," he said. "You see, the pollen and spores--"
"Stop!" she said. "Stop right there. They change from pale yellow to brown to black. Am I right?"
"Right," he said. He was matter-of-fact in tone. He was, among other things, an oil geologist, while she was not. Oil companies had been using the colors of fossil pollen and fossil spores to help identify rock formations that had achieved the sorts of temperatures in which oil might form. Land-based plants, with their pollen and spores, had not developed on earth until a hundred and fifty million years after the beginning of the Paleozoic era, however. Nor would they ever be as plentiful and as nearly ubiquitous as marine fossils. Hearing Leonard Harris mention oil companies and their use of color alteration in pollen and spores, Anita realized in the instant that she had --in her words--"reinvented the wheel." And then some. She had not known that pollen and spores were used as geothermometers in the oil business, and now that she knew it she could see at once that conodonts used for the same purpose would have different geographical applications, covering greater ranges of temperature and different segments of time.
"I think I can do the assessments easier and better by using conodonts," she said to Harris. "Conodontschange color, too, and in the same way."
It was his turn to be surprised. "How come I never heard about that?" he said.
She said, "Because no one knows it."
Petroleum--the transmuted fossils of ocean algae--forms when the rock that holds the fossils becomes heated to the temperature of a cup of coffee and remains as warm or warmer for at least a million years. The minimal temperature is about fifty degrees Celsius. At lower temperatures, the algal remains will not turn into oil. At temperatures hotter than a hundred and fifty degrees, any oil or potential oil within the rock is destroyed. ("The stuff is there, throughout the Appalachians. You look at the rocks and you see all this dead oil.") The narrow "petroleum window," as it is called--between fifty degrees and a hundred and fifty degrees--is scarcely a fourteenth part of the full temperature variation of the crust of the earth, a fact that goes a long way toward explaining how the human race could have used up such a large part of the world's petroleum in less than a century. Not only must the marine algae have been buried for adequate time at depths where temperatures hover in the window but once oil has formed it is subject to destruction underground if for one reason or another the temperature of its host rock rises.
Natural gas is to oil as politicians are to statesmen. Any organic material whatsoever will form natural gas, and will form it rapidly, at earth-surface temperatures and on up to many hundreds of degrees. In Anita's words: "You get natural gas as soon as anything drops dead. For oil, the requisites are the organic material and the thermal window. When they look for oil, they don't know what they've got until they drill a hole." In trying to figure out where to drill, geologists have an obvious need for geothermometers. Pollen and spores are of considerable use, but only when they have fossilized in certain rocks. Moreover, they are absent altogether from early Paleozoic times, and they are extremely rare in rock from the deep sea.
Leonard Harris asked Anita how many years she had been "sitting on" her discovery about conodonts.
About ten, she told him. The last thing she had wished to do was to keep it secret, but no one had shown much interest. She gave him slides of the New York State east-west series, and told him that a comparable set could be got together for Pennsylvania, too. Harris went south and traversed the state of Tennessee, collecting carbonate rocks that were close in age, and when Anita ran the conodonts she found the color alterations quite the same as in the northern states--dark in the east, pale in the west. Leonard and Anita reported all this to Peter Rose, leader of the Oil & Gas Branch, pointing out that the variations in conodont color could lead to a cheapand rapid technique of finding rock in the petroleum window. Rose said he couldn't understand why no one in the United States had ever thought of this if it was as obvious as all that. Anita told him that for years she had been puzzled by the same question, since the procedure would be one that "any idiot ought to be able to follow, because all you need is to be not color-blind."
At Rose's request, Anita's division of the Geological Survey allowed her to work two days a week on conodonts. Weekends, she worked on them at home. Actual temperature values had not been assigned to the varying colors. She did so in a year of experiments. She began with the palest of conodonts from Kentucky and heated them at varying temperatures until they became canary and golden and amber and chocolate and cordovan, black, and gray. With enough added heat, they would turn white and then clear. At nine hundred degrees Celsius, they disintegrated. By cooking her samples in a great many variations of the ratio of time to temperature, she was able to develop a method of extrapolating laboratory findings onto the scale of geologic time. She concluded that pale-yellow conodonts could remain at about fifty degrees indefinitely without changing color. If they were to remain at sixty to ninety degrees for a million years or more, they would be amber. The earth's thermal gradient varies locally, but generally speaking the temperature of rock increases about one degree Celsius for each hundredfeet of depth. A conodont would have to be lodged in rock buried three thousand to six thousand feet in order to experience temperatures of the sort that would turn it amber. At depths of nine thousand to fifteen thousand feet, she discovered, conodonts would turn light brown in roughly ten million years. If they spent ten million years at, say, eighteen thousand feet, they would be dark brown. In comparable amounts of time but at greater and greater depths, they would turn black, gray, opaque, white, clear as crystal. Anita also cooked conodonts in pressure bombs, because it had been suggested to her that the pressures of great tectonism--the big dynamic events in the crust, with mountains building and whole regions being kneaded like dough--might also affect conodont colors. Her experiments convinced her that pressure has little effect on color; heat is what primarily causes it to change.
Of course, plenty of heat is produced by deep burial during major tectonic events. Her conodonts from New Jersey were black and from Kentucky pale essentially because huge disintegrating Eastern mountain ranges had buried the near ones very deep and the far ones scarcely at all. The East is for the most part the wreckage of the ancestral Appalachians, and--as is exemplified in the Devonian rock of New York--the formations are thickest close to where the mountains stood. A continuous sedimentary deposit that is thousands of feet thick in eastern Pennsylvania may be ten feet thick in Ohio.Where oil was first discovered in western Pennsylvania, it was seeping out of rocks and running in the streams. As a natural lubricant, it is of a character and purity so remarkable that it can virtually be put into a Mercedes without first passing through a refinery. People used to buy it and drink it for their health. Anita looked at conodont samples from rock that surrounded this truly exceptional oil. In the temperature range of eighty to a hundred and twenty degrees, they were in the center of the petroleum window. They were golden brown.
With a year of tests run, with Kodachrome pictures, with graphs and charts of what she called her "wind-tunnel models," she was prepared to tell her story. The Geological Society of America was to meet in Florida in November, 1974, and she arranged to deliver a paper there. "I prepared carefully --I always do--so I wouldn't phumpfer. But the G.S.A. meeting was not momentous. They were academics, and not particularly knowledgeable about exploration techniques." Five months later, scarcely knowing what to anticipate, she went to Dallas and spoke before the American Association of Petroleum Geologists. It was the same show, but this time it was playing in the right house. Requests and invitations poured upon her from oil companies wherever they might be, and from geological societies situated in oil centers like Calgary and Tulsa. "It filled a big hole in their technology," Anita has said, recalling those days. "They have to be able to assessthe thermal level of deposits, and this was a simple way to do it."
Anita is now a conodont specialist for the United States Geological Survey, full time. She lives in Maryland. Her home is an island in flower beds and lawn. On weekday mornings, she gets up at fivethirty and rides to work in Washington on a Trailways bus. Her laboratory is in the Smithsonian, where she is largely on her own in shaping her research. Oil companies have continued to beat the path to her door, as have oil geologists from every continent but Antarctica, including large delegations from the Chinese geological survey. While oil prospectors are using brown and yellow conodonts to guide them to the thermal window, mineral prospectors are using white ones in the search for copper, iron, silver, and gold. White conodonts and clear conodonts, products of the highest temperatures, suggest the remains of thermal hot spots, thermal aureoles, ancient hydrothermal springs--places where metallic minerals would have come up in solution to be precipitated out into veins.
Soon after her discovery, universities began calling her, and, ultimately, the American Association for the Advancement of Science. She was pleased to appear at places like Princeton, pleased to be given an opportunity to demonstrate what could be learned elsewhere. Women students were in her audience now. In the late nineteen-seventies, she and her colleagues published a succession of scientificpapers whose title pages perforce encapsulated not only their professional endeavors but something of their private lives. The "senior author" of a scientific publication is the person whose name is listed first and whose work has been of primary importance to the project, while other authors are listed more or less in diminishing order, like the ingredients on a can of stew. The benchmark paper came in 1977. Entitled "Conodont Color Alteration--an Index to Organic Metamorphism," it was "by Anita G. Epstein, Jack B. Epstein, and Leonard D. Harris." Then, in 1978, came "Oil and Gas Data from Paleozoic Rocks in the Appalachian Basin: Maps for Assessing Hydrocarbon Potential and Thermal Maturity (Conodont Color Alteration Isograds and Overburden Isopachs)"--virtually an oil-prospecting kit, a highly specialized atlas--"by Anita G. Harris, Leonard D. Harris, and Jack B. Epstein." And scarcely a year after that appeared a summary document called "Conodont Color Alteration, an Organo-Mineral Metamorphic Index, and Its Application to Appalachian Basin Geology"--"by Anita G. Harris."
Copyright © 1982, 1983 by John McPhee
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