Carbonaceous materia

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By weight, any rock that is half carbonaceous material is coal. Its density is roughly ten times the density of peat. In the United States, there is enough peat to keep Ireland warm for a thousand years. The United States uses almost none of it, because the United States also happens to have a great deal more coal than any other country in the world. Peat that remains near the surfa ce will never become coal. Buried three-quarters of a mile, it becomes bituminous. With a microscope, you can see wood and bark, leaves and roots, seed coats and spores in bituminous coal-and even identify the plants they came from. Buried deeper and folded severely co-working space breda under pressure, it becomes anthracite. Anthracite is roughly ninetyfive per cent carbon and is so hard that it fractures conchoidally, like an arrowhead. Anthracite is iridescent, and burns with a clear blue flame. Coal is a record of tectonics. In late Pennsylvanian time, when the third set of mountains came up in the east and shed still another wedge of debris, kneading it into what had gone before, the great pressure, deep burial, and severe folding produced the anthracites of eastern Pennsylvania, the pod-shaped coalfields of the folded-andfaulted mountains, which erosion and isostasy have lifted from the depths. Anthracite seams are often upside down or standing on end. Here in the Allegheny Plateau, burial was reasonably deep but tectonic pressures were co-working space amersfoort minor, and the result is a lesser grade of coal. We stopped and tried to .collect some but had difficulty finding a sample that would not break up in the hand. “This is very flaky, high-ash coal,” Anita said. “People take it anyway. They come out to these roadcuts with buckets and take it home to burn.”

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Working in Alaska

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More recently, working in Alaska, she had seen the sequence again, this time in tightly banded concentration, for the “American” conodonts were from reefs around Ordovician volcanic islands with steeply plunging sides and the “Scandinavian” conodonts were from cold deeps nearby. Swerving to avoid a pothole, Anita said, “The plate-tectonics boys look at faunal lists and they go hysterical moving continents around. It’s not the paleontologists doing it. It’s mostly the geologists, misusing the paleontology. Think what geologists would make of the present east coast of the United States if they did not understand oceanography and the resulting distribution of modem biota . . Put yourself forty or fifty million years from now trying to reconstruct the east coast of the United States by looking at the remains in the rock. God help you, you would probably have Maine connected to Labrador, and Cape Hatteras to southern Florida. You’d conference room breda have a piece of Great Britain there, too, because you see the same fauna. Well, did you ever hear of ocean currents? Did you ever hear of the Gulf Stream? The Labrador Curre;it? The Gulf Stream brings fauna north. The Labrador Current brings fauna south. I think that a lot of the faunal anomalies you see in the ancient record, and which are explained by invoking plate tectonics, can be explained by ocean currents bringing fauna into places they shouldn’t be. In the early days of plate tectonics, a lot of us, including me, jumped on the bandwagon in order to explain the distribution anomalies we were seeing not only in the eastern Appalachians but in North America as a whole. When we better understood the paleoecologic controls on the animals some of us were working on, there was no reason to invoke plate tectonics.” The conference room amersfoort experience was cautionary, to say the least. It did not close her mind to plate tectonics, but it opened a line of suspicion and made her skeptical of the theory’s insistent universality. Her discomfort varies with distance from the mobile ocean floors. She likes to describe herself as a “protester.” The protest is not so much against the theory itself as against excesses of its application-up on the dry land.

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Four hundred million years

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After standing there more than four hundred million years, the dolomite would be quarried to become for many miles the concrete surface of Interstate So and to become as well the foundations of most of the tall buildings that now proclaim Chicago, as the atoll did in Silurian time. Interstate So actually crosses the atoll on bridges above the quarry, which is as close an approximation to the Grand Canyon as Chicago is likely to see, and may be its foremost attraction. Beyond the atoll, you would have come to other atolls and hypersaline seas. When water is about three times as salty as the ocean, gypsum will crystallize out. Sticking up from the  co-working space breda bottom in central Ohio were daggerlength blades of gypsum crystal. You would have been bucking hot tropical trade winds then, blowing toward the equator, evaporating the knee-deep sea. East of Youngstown, red muds clouded the water-muds coming off the approaching shore. The beach was in central Pennsylvania now, near the future site of Bloomsburg, near the forks of the Susquehanna. The great sedimentary wedge of the delta complex had grown a hundred miles. The Taconic mountains were of humble size. The steep braided rivers were gone, their wild conglomerates buried under meandering mudbanked streams moving serenely through a low and quiet country-a rose-and-burgundy country. There were green plants in the red earth, for the first time ever. Walking forward through time and past the tilted strata of the Water Gap, we had come to sandstones, siltstones, and shales, in various hues of burgundy and rose. In the irregular laminations of the rock-in its worm burrows, ripples, and crossbeds-Anita saw and described tidal channels, tidal flats, a river coming into an estuary, a barrier bar, a co-working space amersfoort littoral sea. She saw the delta, spread out low and red, the Taconic mountains reduced to hills. We had left behind us the rough conglomerates and hard gray quartzites that had come off the Taconic mountains when they were high-the formation, known as Shawangunk, that forms the mural cliffs above the Delaware River. (The quartzites are paradisal to rappeling climbers, who refer in their vernacular to “the gap rap,” a choice part of “the Gunks.”)

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Petroleum

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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 tum 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 flexplek huren breda 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 one 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 flexplek huren amersfoort 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.

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The odds

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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 the plates, 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 flexplek huren groningen diamonds, where they cool suddenly and enter a state of precarious preservation tliat somehow betokens to human beings a touching sense of “forever.” Diamonds shoot like bullets through the earth’s crust. Nonetheless, tl1ey 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 i867 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-inoor, 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  flexplek huren apeldoorn 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 ten-millionth 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.

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The mechanics of the seafloor

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It was on the mechanics of the seafloor that geology’s revolutionary inquiries were primarily focussed in the early days. Harry Hess, a mineralogist who taught at Princeton, was the skipper of an attack transport during the Second World War, and he carried troops to landings-against the furious defenses of Iwo Jima, for example, and through rockets off the beaches of Lingayen Gulf. Loud noises above the surface scarcely distracted him. He had brought along a new kind of instrument called a Fathometer, and, battle or no battle, he never turned it off. Its stylus was flexplek huren breda drawing pictures of the floor of the sea. Among the many things he discerned there were dead volcanoes, spread out around the Pacific bottom like Hershey’s Kisses on a tray. They had the arresting feature that their tops had been cut off, evidently the work of waves. Most of them were covered with thousands of feet of water. He did not know what to make of them. He named them guyots, for a nineteenth-century geologist at Princeton, and sailed on. The Second World War was a technological pifiata, and, with their new Fathometers and proton-precession magnetometers, oceanographers of the nineteen-fifties-most notably Bruce Heezen ap.d Marie Tharp at Columbia University-mapped the seafloor in such extraordinary detail that in a sense they were seeing it for the first time. (Today, the very best maps are classified, because they reveal the places where submarines hide.) What stood out even more prominently than the deep trenches were mountain ranges that rose some six thousand feet above the general seafloor and ran like seams through every ocean and all around the globe. They became known as rises, or flexplek huren amersfoort ridges-the Mid-Atlantic Ridge, the Southeast Indian Ocean Ridge, the East Pacific Rise. They fell away gently from their central ridgelines, and the slopes extended outward hundreds of miles, to the edges of abyssal plains-the Hatteras Abyssal Plain, the Demerara Abyssal Plain, the Tasman Abyssal Plain. Right down the spines of most of the submarine cordilleras ran high axial valleys, grooves that marked the summit line.

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The local doorbell

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We were off on dirt roads now with a cone of dust behind us, which Deffe yes characterized as the local doorbell. He preferred not to ring it. This talkative and generous professor-who ordinarily shares his ideas as rapidly as they come to him, spilling them out in bunches like grapes-was narrow-eyed with secrecy today. He had stopped at a courthouse briefly, and-an antic figure, with his bagging sweater and his Beethoven hair-had revealed three digits to a county clerk in requesting to see a registry of claims. The claims were coded in six digits. Deffeyes kept the fourth, fifth, and sixth to himself like cards face down on a table. He found what he sought in the book of claims. Now, fifty miles up the valley, we had long since left behind us its zakelijke energie only town, with its Odd Fellows Hall, its mercantile company, its cottonwoods and Lombardy poplars; and there were no houses, no structures, no cones of dust anywhere around us. The valley was narrowing. It ended where ranges joined. Some thousands of feet up the high face of a distant and treeless mountain we saw an unnaturally level line. “Is that a road?” I asked him. “That’s where we’re going,” he said, and I wished he hadn’t told me. Looking up there, I took comfort in the reflection that I would scarcely be the first journalist to crawl out on a ledge in the hope of seeing someone else get rich. In i86g, the editor of the New York Herald, looking over his pool of available reporters, must have had no difficulty in choosing Tom Cash to report on supergene enrichments. Cash roved Nevada. He reported from one place that he took out his pocketknife and cut into the wall of a shaft, removing an ore of such obviously high assay that he could roll it in his fingers and it would not crumble. Cash told the mine owner that he feared being accused of exaggeration-“of making false statements, puffing” with resulting damage to his zakelijke energie vergelijken journalistic reputation. There was a way to avoid this, he confided to the miner. “I would like to take a sample with me of some of the richest portions.” The miner handed him a fourteen-pound rock containing about a hundred and fifty troy ounces of silver (seventy-three per cent). In the same year, Albert S. Evans, writing in the San Francisco Alta California, described a visit with a couple of bankers and a geologist to a claim in Nevada where he was lowered on a rope into a mine.

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Generosity

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Some of these time lines were bolder than otl1ers, and none more so than the one tlrnt underlined the first appearance of megascopic fossils in abundance in the world. It marked a great and sudden explosion of life, all the major phyla having developed more or less at the same time and now acquiring skeletons and shells and teeth and other hard components that allowed them individually to be reported to the future. Because rock that held these early fossils was first zakelijke energie studied on Harlech Dome and adjacent Welsh terrains, geologists named the system Cambrian, after the Roman name for Wales. They then named the Silurian for a Welsh tribe that bitterly defied the Romans. After some years and more comparative study, an argument broke out over tl1e Cambra-Silurian line, a scientific battle royal in which the Cambrian forces tried to move their banner fmward through time and the Silurian proponents attempted to push theirs back. The disputed block of time became a sort of demilitarized zone. Friendships came unstuck. The standoff lasted for decades, until some genius in scientific diplomacy suggested that the disputed time had enough characteristics of its own to be given the status of a discrete period, an appropriate name for which-in honor of another tribe of intractable Welsh belligerents-would be Ordovician. There was a lot of room for generosity. There was plenty of time for all. Cambrian-544 to 490. Ordovician-490 to 439. Silurian-439 to 408 million years before the present. A British geologist went to Russia and after a season or two’s tapping at the Urals named still zakelijke energie vergelijken another period in time, and system of rock, for the upland oblast of Perm. There were formations in Perm with a fossil story distinctly their own that were superimposed-as they happen to be in Pennsylvania, as they happen to be at the rim of the Grand Canyon-upon the Carboniferous. What was distinct about the character of the Permian assemblages was not only the forms to which they had evolved but also their absence in great numbers from higher, younger strata.

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Captain Howard Stansbury

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In age, the blue stone approached five hundred million years. Captain Howard Stansbury, USA, whose name would rest upon the mountains of which the rock was a component, was dpproaching fifty when he came into the Great Basin in i849. He he’d been making lighthouses in Florida. The government preferred that he survey the salt lake. With sixteen mules, a water keg, and some India-rubber bags, he circumambulated the lake, and then some. People told him not to try it. He zakelijke energie ran out of water but not of luck. An8 he came back with a story of having seen-far out on the westward flats-scattered books, clothing, trunks, tools, chains, yokes, dead oxen, and abandoned wagons. The Donner party went around the nose of the Stansburys in late August, i846, rock on their left, lake marshes on their right. This huge blue roadcut, in its supranatural way, would have frightened them to death. They must have filed along just about where Deffeyes had parked the pickup, on the outside shoulder of the interstate. Deffeyes and I went back across the road, waiting first for a three-unit seven-axle tractor-trailer to pass. Deffeyes described it as “a freaking train.” Stansbury Mountains, Skull Valley …T he Donner party found good grass in Skull Valley, and good water, and a note by a post at a spring. It had been tom to shreds by birds. The emigrants pieced it together. “Two days-two nights-hard driving-cross desertreach water.” They went out of Skull Valley over the Cedar Mountains into Ripple Valley and over Grayback Mountain to the Great Salt Lake Desert. Grayback Mountain was basalt, like the Watchungs of New Jersey. The New Jersey basalt flowed about two hundred million zakelijke energie vergelijken years ago. The Grayback Mountain basalt flowed thirty-eight million years ago. Well into this century, it was possible to find among the dark-gray outcrops of Grayback Mountain pieces of wagons and of oxhom, discarded earthenware jugs. The snow suddenly gone now, and in cold sunshine, Deffeyes and I passed Grayback Mountain and then had the Great Salt Lake Desert before us-the dry bed of Bonneville-broader than the periphery of vision. The interstate runs close to but not parallel to the wagon trail, which trends a little more northwesterly.

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Precious little granite

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The Sierra Nevada is renowned throughout the world for its relatively young and absolutely beautiful granite. There is precious little granite in the Sierra. Yosemite Falls, Half Dome, El Capitan-for the most part the “granite” of the Sierra is granodiorite. It has always been difficult enough to hold in the mind that a magma which hardens in the earth as granite will-if it should flow out upon the earth-harden as rhyolite, that what hardens within the earth as diorite will harden upon the earth as andesite, that what hardens within the earth as gabbro will harden upon the earth as basalt, the difference from pair to pair being a matter of chemical composition and the differences withineach pair being a matter of texture and of zakelijke energie vergelijken crystalline form, with the darker rock at the gabbro end and the lighter rock the granite. All of that-not to mention such wee appendixes as the fact that diabase is a special texture of gabbro-was difficult enough for the layman to remember before the diffractometers and the spectrometers and the electron probes came along to present their multiplex cavils. What had previously been described as the granite of the world turned out to be a large family of rock that included granodiorite, monzonite, syenite, adamellite, trondhjemite, alaskite, and a modest amount of true granite. A great deal of rhyolite, under scrutiny, became dacite, rhyodacite, quartz latite. Andesite was found to contain enough silica, potassium, sodium, and aluminum to be the fraternal twin of granodiorite. These points are pretty fine. The home terms still apply. The enthusiasm geologists show for adding new words to their conversation is, if anything, exceeded by their affection for the old. They are not about to drop granite. They say granodiorite when they are in church and granite the rest of the week. When I was seventeen and staring up the skirts of .eastern valleys, I was taught the rudiments of what is now referred to as the Old Geology. The New Geology is the package phrase for the effects of the revolution that occurred in eaith science in the nineteensixties, when geologists clambered onto seafloor zakelijke energie vergelijken spreading, when people began to discuss continents in terms of their velocities, and when the interactions of some twenty parts of the globe became known as plate tectonics.

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