Maandelijks archief: januari 2018

Transverse dislocations

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“I conceive these transverse dislocations to pervade all the great ridges and valleys of our Appalachian region,” he wrote, “and to be a primary cause of most, if not all, of those deep notches which are known by the name of Water Gaps, and which cleave so many of our high mountain ridges to their very bases.” There were some thin green beds among the Bloomsburg reds. Anita said they were the Kupferschiefer greens that had given false hope to the Dutch. Whatever else there might be in the Bloomsburg Delta, there was not a great deal of copper. In the eighteen-forties, the mines of the Minisink were started up anew. They bankrupted out in a season. The Reverend F. F. Ellinwood delivered the “Dedication Sermon” in the Church of the Mountain, village of Delaware Water Gap, Pennsylvania, August 29, i854, a year that Ellinwood placed in the sixth millennium after Creation. “The rude blasts of six thousand winters have co-working space rotterdam howled in undaunted wildness over the consecrated spot, while yet its predicted destiny was not fulfilled,” he told the congregation. “But here, at length, stands, in very deed the church firmly built upon the rock, and it is our hope and prayer that the gates of Hell shall not prevail against it …. For many centuries past, has Jehovah dwelt in the rocky fastnesses of this mountain. Ere there was a human ear to listen, His voice was uttered here in the sighing of the breeze and the thunder of the storms, which even then were wont to writhe in the close grapple of this narrow gorge. Ere one human footstep had invaded the wildness of the place, or the hand of art had applied the d1ill and blast to the silent rock, God’s hand was working here alone-delving out its deep, rugged pathway for yonder river, and clothing those gigantic bluffs and terraces with undying verdure, and the far gleaming b1ightness of their laurel bloom.” The hand of art, that very summer, was blasting the Delaware, Lackawanna & Western Railroad into the silent rock. Stagecoaches would soon leave the scene. A pathway by the river was replaced with rails. The co-working space amsterdam sycamores that shaded it were felled. A telegraph wire was strung through the gap. Given a choice between utility and grandeur, people apparently wanted to have it both ways. Trains would travel in one direction carrying aristocrats and in the other carrying coal.

Requests and invitations

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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 assess the thermal level of deposits, and this was a simple way to do it.” Anita became 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. She gets up at four-thirty and drives to work at the Survey’s headquarters in Reston, Virginia. 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 flexplek huren rotterdam 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. 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 nineteenseventies, she and her colleagues published a succession of scientific papers 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 i977. Entitled “Conodont Colar Alteration-an Index to Organic Metamorphism,” it was “by Anita G. Epstein, Jack B. Epstein, and Leonard D. Harris.” Then, in i978, came “Oil and Gas flexplek huren amsterdam Data from Paleozoic Rocks in the Appalachian Basin: Maps for Assessing Hydrocarbon Potential and Thermal Maturity (Conodont Colar 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 Colar Alteration, an Organo-Mineral Metamorphic Index, and Its Application to Appalachian Basin Geology”-“by Anita G. Harris.”

An external mold

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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  flexplek huren utrecht police. There were flashing lights. Against the side of an abused Pontiac, a 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 to be 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 flexplek huren schiphol 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.

Extensive paleomagnetic

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On that assumption, they extrapolated a much more extensive paleomagnetic time scale. (Improved radiometric dating later endorsed the accuracy of the method.) And with that scale they swiftly mapped the history of ocean basins. Compared with a geologic map of a continent, it was a picture handsome and spare. As the paleomagnetist Allan Cox, of Stanford University, would describe it in a book called Plate Tectonics and Geomagnetic Reversals, “The structure of tl1e seafloor is as simple as a set of tree rings, and like a modern bank check it carries an easily decipherable magnetic signature.” Meanwhile, geophysicists at Toronto, Columbia, Princeton, and the Scripps Institution of Oceanography were filling in the flexplek huren rotterdam last major components of the plate-tectonics paradigm. They figured out the geometry of moving segments on a sphere, showed that deformation happens only at the margins of plates, charted the relative motions of the plates, and mapped for the first time the plate boundaries of the world. If it was altogether true, as Hess had claimed, that with relative frequency “the whole ocean is virtually swept clean,” then old rock should be absent from deep ocean floors. Since ig68, the drill ships Glomar Challenger and JOIDES Resolution have successively travelled the world looking for, among other things, the oldest ocean rocks. The oldest ever found is Jurassic. In a world that is +56 billion years old, with continental-shield rock that has been dated to 3.96, it is indeed astonishing that the oldest rock that human beings have ever removed from a seafloor has an age of a hundred and eightyfive million years-that the earth is twenty-five times as old as the oldest rock of the oceans. In i969, it seemed likely that the oldest ocean floor would be found in the Northwest Pacific. The Glomar Challenger went there to see. Two Russians were aboard who believed that rock older than Jurassic-rock of the Paleozoic, in flexplek huren amsterdam all likelihood-would be discovered. They took vodka with them to toast the first trilobite to appear on deck. Trilobites, index fossils of the Paleozoic, came into the world at the base of the Cambrian and went out forever in the Permian Extinction-sixty-five million years before the age of the oldest rock ever found in modern oceans. As expected, the oceanic basement became older and older as the ship drilled westward from Hawaii.

The old miners

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I was looking for mines that were not marked on maps. I could see dumps in some places. They stood out light gray. The old miners made dumps of rock that either contained no silver at all or did not contain enough silver to be worth their while at the time. I tried to guess roughly the volume of the dumps. Mill tailings made unnatural light-gray smudges on the pictures. Some of the tailings and dumps I found in these mountains appear on no maps I’ve seen.” He flew to Nevada, chartered a light plane, and went over the country a thousand feet above the ground, taking fresh private pictures with a telephoto lens. When he flew over places where other scavengers looked up and waved, he crossed those places off his list. He went in on the zakelijke energie ground then, to a number of sites, and collected samples. He had machines at home that could deal with the samples in ways unheard of just a few years before, let alone in the nineteenth century. Kicking at old timbers, he looked at the nails. Wire nails came into use in igoo and are convenient index fossils of the Age of Cyanide. He hoped for square nails. Deffeyes was on his own now. His relationship with Eocene had faded out after they had chosen, on various points, to follow counsel other than his, and they transferred their scrutiny to Arizona, preferring not to cope with winter. One day in Princeton, his wife, Nancy Deffeyes, was looking through a stack of hundred-year-old Engineering & Mining Journals when she found a two-line reference to certain mining efforts in the eighteen-seventies that eventually assumed prominence on her husband’s list, and that was what had brought him here and why we were crawling like a Japanese beetle zakelijke energie vergelijken across the face of this mountain. We turned a last corner, with our inner wheels resting firmly on the road and the two others supported by Deffeyes’ expectations. Now we were moving along one wall of a big V-shaped canyon that eventually became a gulch, a draw, a crease in the country, under cottonwoods. In the upper canyon, some hundreds of acres of very steep mountainside were filled with holes and shafts, hand-forged ore buckets, and old dry timbers.

Berkeley

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The Berkeley calculations suggested an asteroid about six miles in diameter hitting the earth with a punch of a hundred million megatons, making a crater a hundred miles wide. Such an occurrence-which could repeat itself tomorrow afternoon, there being several hundred big asteroids out there in threatening orbits -would have sent up a mushroom cloud containing some thirty thousand cubic kilometres of pulverized asteroid and terrestrial crust, part of which would have gone into the stratosphere and spread quickly over the earth, keeping sunlight off the lands and seas and suppressing photosynthesis. A decade after the publication of zakelijke energie the Berkeley hypothesis, Chicxulub Crater was discovered, buried five hundred metres under Yucatan. Evidently made by an Apollo Object, it is a hundred and ten miles wide. On August 26 and 27, i883, when the island Krakatoa, in the Sunda Strait, exploded with great violence, it sent less than twenty cubic kilometres of material into the air, but within a few days dust had spread above the whole earth, turning daylight into dusk. It made exceptionally brilliant sunsets for two and a half years. Edmund Halley, who died when James Hutton was fifteen, once wrote a paper suggesting that the way God started Noah’s Flood was by directing a big comet into collision with the earth. The Cretaceous Extinction, whatever its cause, was one of the two most awesome annihilations of life in the history of the world. With the Permian Extinction before it, it framed the Mesozoic, an era of burgeoning creation within deadly brackets of time. For establishing our bearings through time, we obviously owe an incalculable debt to vanished and endangered species, and if the condor, the kit fox, the human being, the black-footed ferret, and the three-toed sloth are at the head of the line to go next, there is less cause for dismay than for zakelijke energie vergelijken placid acceptance of the march of prodigious tradition. The opossum may be Cretaceous, certain clams Devonian, and oysters Triassic, but for each and every oyster in the sea, it seems, there is a species gone forever. Be a possum is the message, and you may outlive God.

Toano Range

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The tuff was hard, heavy, crystalline rock, freckled with feldspars and quartz. You would never dig a city out of that. The ranges now were anything but buried,[ and Pilot Peak reached above the shadowed basin and high into sunlight, a mile above its valleys. Soon we were climbing the Toano Range. “Here comes another roadcut,” said Deffeyes near the summit. “You can feel them coming on. The Taconic Parkway would I drive you nuts. I-So gives you one when you’re ready for it.” What it gave in the Toanos was granite-not some sibling, son, or c01pin but granite himself: sparkling black hornblendes evenly spaced through a snowy field of feldspars and quartz. It was of much the same age as the celebrated rock of the Sierra. Its presence here suggested that the great crustal meltings in the tectonic drama farther west put out enough heat even in eastern Nevada to cook up this batch of fresh granite. In this manner we moved along from roadcut t9 roadcut, range
to range, like barnyard zakelijke energie poultry pecking up rock, seeing what the fault blocks had lifted from below. We crossed the Goshute Valley and went up into the Pequops into red Devonian shales, Devonian siltstones, Devonian limestones-a great many millions of years older than the granite, and from another world. These were marine rocks (by and large), full of crinoids and other marine fossils. Nothing about their appearance differed from sediment that might have collected over Illinois or Iowa in midcontinental, epicratonic seas. They provided not so much as a hint that they were actually from the continental shelf, that Pequop Summit is more or less where North America ended in Devonian time. The first attempt to move covered wagons directly across the continent to California ended at the Pequops, too. The wagons were abandoned at a spring by the eastern base of the mountains, a short hike off the interstate. Later emigrants made cooking fires with the wood of the wagons. Deffeyes was spitting out the siltstones but chewing happily on the shales. The oolites of the Great Salt Lake were forming in the present. The dolomite of tlrn Stansbmy Mountains was almost five hundred million years old. The tuff had been welded for zakelijke energie vergelijken thirty million years. The age of the granite was a hundred million years. The rock of Pequop Summit was four times as old as that.

Meltwater

Afbeeldingsresultaat voor site:ilocate.nl

To poke around in a preliminary way, Deffeyes and I went up to the Palisades Sill, where I was to return with Karen Kleinspehn, borrowed some diabase with a ten-pound sledge, and then began to travel westward, traversing the Hackensack Valley. It was morning. Small airplanes engorged with businessmen were settling into Teterboro. Deffeyes pointed out that if this were near the end of Wisconsinan time, when the ice was in retreat, those airplanes would have been settling down through several hundred feet of water, with the runway at the bottom of a lake. Glacial Lake Hackensack was the size of Lake Geneva and was host to many islands. It had the Palisades Sill for an eastern shoreline, and on the west the lava hill that is now known zakelijke energie vergelijken as the First Watchung Mountain. The glacier had stopped at Perth Amboy, leaving its moraine there to block the foot of the lake, which the glacier fed with meltwater as it retreated to the north. Some two hundred million years earlier, the runway would have been laid out on a baking red flat beside the first, cooling Watchung-glowing from cracks, from lava fountains, but generally black as carbon. Basalt flows don’t light up the sky. Three hundred million years before that, the airplanes would have been settling down toward the same site through water-in this instance, salt water-on the eastern shelf of a broad low continent, where an almost pure limestone was forming, because virtually nothing from the worn-away continent was eroding into the shallow sea. Three random moments from the upper ninth of time. In Paterson, I-80 chops the Watchung lava. Walking the cut from end to end, Deffeyes picked up some peripheral shale-Triassic red shale. He put it in his mouth and chewed it. “If it’s gritty it’s a silt bed, and if it’s creamy it’s a shale,” he said. “This is creamy. Try it.” I would not have thought to put it in coffee. In the blocky basaltic wall of the road, there were many small pockets, caves the size of peas, caves the size of lemons. As magma approaches the surface of the earth, it is so perfused with gases that it fizzes like ginger ale. In cooling basalt, gas bubbles remain, and form these minicaves. For a century and more, nothing much fills them. Slowly, though, over zakelijke energie a minimum of about a million years, they can fill with zeolite crystals. Until well after the Second World War, not a whole lot was known about the potential uses of zeolite crystals.

Eclectic petrologue

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A year or so later, in a random conversation with this same eclectic petrologue, I asked if he thought we might find a Talk of the Town piece for The New Yorker in a roadcut near the city. We could look at the blast-exposed face of the rock, read its history, and tell it in the first-person plural. While we were still planning this short trip, I asked him if there would not be an even better story in a journey north from roadcut to roadcut-for example, up the Northway’s stunning route through the Adirondacks. “Not on this continent,” said Deffeyes. “If you want to zakelijke energie do that sort of thing on this continent, go west-go across the structure.” In one moment, bounding and rash, my thoughts raced to San Francisco with roadcuts lining the route like billboards, each with its own message. “Why not go all the way?” I said to him. Two weeks later, we were looking for silver in Nevada. Deffeyes has stood beside this project for twenty flattering years, always seeming to assume that my comprehension and capabilities are twice their actual size, never showing the slightest sign of stress, or even awareness, when he is talking six to eight metres above my head. As widely read as if he were a professor of comparative literature, he intuitively understood the goal I had set up: to present his science and its practitioners in a form and manner that was meant to arrest the attention of other people while achieving acceptability in the geologic community. I was rnuve even to think of such a thing, and a nervous wreck for months on end, but I learned a lot in twenty years. Deffeyes searched his mind and the geologic literature, and suggested-for the Appalachians, the Rocky Mountains, and California-geologists I might travel with. He called them, interested them in what I was trying to do, and zakelijke energie vergelijken asked if they would help. Since I travelled with all of them in that first year, they in turn became twenty-year counsellors as well as companions.