NOAA COMMENT use for understanding cells that do not communicate using electrical impulses. It is this view that has perpetuated our comparative ignorance about glia. Moreover, the exclusion of glia from the BRAIN Initiative underscores a more general problem with the project: the assumption that enough measuring of enough neurons will in itself uncover ‘emergent’ properties and, ultimately, cures for diseases1,4. Rather than simply materializing from measurements of “every spike from every neuron”1,4, better understanding and new treatments will require hypothesis-directed research. The 302 neurons and 7,000 connections that make up the nervous system of the roundworm Caenorhabditis elegans were mapped in the 1970s and 80s. More than two decades later, little is understood about how the worm’s nervous system produces complex behaviours. In any major mapping expedition, the first priority should be to survey the uncharted regions. Our understanding of one half of the brain (the part comprised of astrocytes, oligodendrocytes and microglia) lags a century behind our knowledge of neurons. I believe that answers to questions about the brain and public support for a large-scale study are more likely to come from expanding the search into this unknown territory. As a first step, tools such as optogenetic methods and mathematical models are needed to assess the number, distribution and properties of different kinds of glial cell in different brain regions, and to identify how glia communicate with each other and with neurons, and what developmental and physiological factors affect this. This exploration into the ‘other brain’ must be done together with the proposed studies of neurons. It cannot be achieved as a by-product of them. ■ R. Douglas Fields is chief of the Nervous System Development and Plasticity Section at the US National Institutes of Health in Bethesda, Maryland. e-mail: fieldsd@mail.nih.gov 1. Alivisatos, A. P. et al. Science 339, 1284–1285 (2013). 2. Kettenmann, H. & Ransom, B. R. (eds) Neuroglia 3rd edn (Oxford Univ. Press, 2013). 3. Fields, R. D. The Other Brain (Simon & Schuster, 2009). 4. Alivisatos, A. P. et al. Neuron 74, 970–974 (2012). 5. Schafer, D. P. et al. Neuron 74, 691–705 (2012). 6. Fields, R. D. et al. The Neuroscientist (in the press). 7. Wake, H. Lee, P. R. & Fields, R. D. Science 333, 1647–1651 (2011). 8. Zatorre, R., Fields, R. D. & Johansen-Berg, H. Nature Neurosci. 15, 528–536 (2012). 9. Han, X. et al. Cell Stem Cell 12, 342–353 (2013). The US research vessel Explorer towed a magnetometer to map fields over the sea floor in 1960. How plate tectonics clicked Fifty years after a paper linked sea-floor magnetic stripes with continental drift, Naomi Oreskes explains its legacy as a lesson in achieving scientific consensus. B y the time German geophysicist Alfred Wegener proposed continental drift in 1912, palaeontologists had long accepted that past connections between now-separate lands explained the spread of similar fossils and rock layers across them. Geologists, too, knew of slabs of Alpine rock that had been displaced hundreds of kilometres during mountain building. But the arguments for continental motions did not gel until the 1960s, when a drastic expansion of geophysical research, driven by the cold war, produced evidence that reopened and eventually settled the debate. One influential study was published1 in Nature 50 years ago this week. British geologists Frederick Vine and Drummond Matthews interpreted stripes of alternating magnetic-field polarity in ocean bedrock as evidence of a spreading sea floor that pushed continents apart. Acceptance that large crustal motions were a reality soon followed, culminating in the theory of plate tectonics. In its slow convergence of ideas and evidence, the history of plate tectonics holds lessons for today’s debates about 5 S E P T E M B E R 2 0 1 3 | VO L 5 0 1 | NAT U R E | 2 7 © 2013 Macmillan Publishers Limited. All rights reserved ELLIOT LIM/CIRES/NOAA/NATL GEOPHYS. DATA CENT. COMMENT The age of ocean rocks increases (red to purple, 0–280 million years) with distance from ridges, where crust is formed, revealing the spread of the sea floor. human-induced climate change. Although science is always evolving, and our attention is drawn to controversy at the research frontier, it is the stable core of ‘consensus’ knowledge that provides the best basis for decision-making. MANTLE CONVECTION Wegener stands out because his solution was close to the one that we now accept, and because our individualist culture encourages us to look for heroes to credit and discrete events to celebrate. But he was not alone in trying to explain commonalities in fossils and rock strata. In the English-speaking world, two of the most important players in developing theories of continental-scale crustal mobility were South African field geologist Alexander du Toit and British geochronologist Arthur Holmes. Du Toit articulated the case in his aptly named 1937 book Our Wandering Continents (Oliver and Boyd). He acted as a clearing house for geologists around the globe, who sent him maps, rocks and fossils. Holmes, working with the Irish geochemist John Joly, suggested that crustal motion was driven by radioactivity and the heat that it emanates, advocating mantle convection as a means of dissipating radiogenic heat and driving continental drift2. Holmes’s 1944 textbook Principles of Physical Geology (Thomas Nelson & Sons) was an introduction to the subject for many students. The discussion was joined by Dutch geodesist Felix Vening Meinesz, who worked in the 1930s in the Indonesian archipelago and, with US geologists Harry Hess and Maurice Ewing, in the Caribbean. Meinesz found that Earth’s gravitational field was weaker than normal above some of the ocean’s deepest regions, which he explained in terms of the buckling of low-density crust into the mantle, dragged down by descending convection currents, and he discussed these ideas with Hess. During the Second World War, Hess found himself in the US Navy, fighting in the Pacific theatre. He did not return immediately to tectonics after the war, but others did, including several British geophysicists led by P. M. S. Blackett and Keith Runcorn. In an effort to understand “More than the origins of Earth’s two dozen magnetic field, they discovered that magscientists netic minerals pointed did the key in different directions work that at different times in created the theory of plate geological history, as if the positions of the tectonics.” poles had changed. Hess was drawn back to the topic after realizing that these ‘apparent polar-wandering paths’ could be explained by the movements of the continents. OCEAN SPREADING Hess suggested that rising mantle-convection cells would drive apart the ocean floor above them, increasing the separation of continents to either side. The idea, which his colleague Robert Dietz christened ‘sea-floor spreading’3, explained the old geological observations and the new geophysical ones, but it did not gain immediate traction. That would take further geomagnetic information. Blackett, a socialist who opposed nuclear proliferation, turned to geomagnetism after the war to distance himself from military work4. But military concerns — particularly the demands of submarine warfare in the atomic age — drove geophysical exploration of the ocean floor, leading to the discovery in 2 8 | NAT U R E | VO L 5 0 1 | 5 S E P T E M B E R 2 0 1 3 © 2013 Macmillan Publishers Limited. All rights reserved the late 1950s of sea-floor magnetic stripes. The stripes were a surprise. In the report of the discovery, oceanographers Ronald Mason and Arthur Raff admitted to being at a loss for an explanation. Others were less stymied. Vine and Matthews, as well as Canadian geophysicist Lawrence Morley, independently had the same idea. If the sea floor was spreading, then magnetic stripes would be expected: rock formed at mid-ocean ridges would take on Earth’s magnetic field, the polarity alternating as the field periodically reversed. It was one thing to say that the oceans were widening, another to link it to global crustal motion. More than two dozen scientists, including women such as Tanya Atwater and Marie Tharp, did the key work that created the theory of plate tectonics as we know it — explaining continental drift, volcanism, seismicity and heat flow around the globe5. In 1965, Canadian geologist Tuzo Wilson proposed a type of ‘transform’ fault to accommodate the spreading sea floor around midocean ridges, which was confirmed by US seismologist Lynn Sykes. Other seismologists demonstrated that in deep-ocean trenches, slabs of crust were indeed being driven into the mantle, and geophysicists worked out how these crustal ‘plates’ move and relate to the features of continental geology. Vine and Matthews’ work is part of a larger story of the growth of Earth science in the twentieth century, made possible by improved technology and greater governmental support after the Second World War. Nearly all seismic and marine geophysical data at the time were collected with military backing, in part because of their cold-war security significance. This era marked a change in the character of modern science. Research today is expensive and largely government-funded; almost COMMENT all major scientific accomplishments are the collective achievement of large teams. This reality — more prosaic than the hagiography of lonely genius — reminds us that although great individuals are worthy of recognition, the strength and power of science lies in the collective effort and judgement of the scientific community. CONSENSUS MATTERS J. R. CANN In recent months, several of my colleagues in climate science have asked me whether the story of plate tectonics holds lessons for their field in responding to those who disparage the scientific evidence of anthropogenic climate change. I believe that it does. Many critics of climate science argue that expert agreement is irrelevant. Science, they claim, advances through bold individuals such as Wegener or Galileo Galilei overturning the status quo. But, contrary to the mythology, even Isaac Newton, Charles Darwin and Albert Einstein worked within scientific communities, and saw their work accepted. In glorifying the lone genius, climate-change dissenters tap into a rich cultural vein, but they miss what consensus in science really is and why it matters. Consensus emerges as scientific knowledge matures and stabilizes. With some notable exceptions, scientists do not consciously try to achieve consensus. They work to develop plausible hypotheses and collect pertinent data, which are debated at conferences, at workshops and in peer-reviewed literature. If experts judge the evidence to be sufficient, and its explanation coherent, they may consider the matter settled. If not, they keep working. History enables us to judge whether scientific claims are still in flux and likely to change, or are stable, and provide a reasonable basis for action. And maturity takes time. Scientific work, compared with industry, government or business, has no deadline. Perhaps for this reason, when Wegener died in 1930, according to his biographers he was confident that other scientists would one day work out how the continents moved, and that this mechanism would be along the lines of his proposal — as indeed it was. Du Toit and Holmes were similarly convinced. The equanimity of these men speaks to their confidence in science as a system. They perceived what historian–philosopher Thomas Kuhn articulated in The Structure of Scientific Revolutions (University of Chicago Press, 1962): that science is a community affair and that knowledge emerges as the community as a whole accepts it. A debate comes to a close once scientists are persuaded that a phenomenon is real and that they have settled on the right explanation. Further discussion is not productive unless new evidence emerges, as it did for continental drift. Anthropogenic climate change has the consensus of researchers. Political leaders who deny the human role in climate change should be compared with the hierarchy of the Catholic church, who dismissed Galileo’s arguments for heliocentrism for fear of their social implications. But what of scientists who in good faith reject the mainstream view? Harold Jeffreys is an intriguing example. An eminent professor of astronomy at the University of Cambridge, UK, Jeffreys rejected continental drift in the 1920s and plate tectonics in the 1970s. He believed that the solid Earth was too rigid to permit mantle convection and crustal motion. His view had a strong mathematical basis, but it remained unchanged, even as evidence to the contrary mounted. If society had faced a major decision in the 1970s that hinged on whether or not continents moved, it would have been foolish to heed Jeffreys and to ignore the larger consensus, backed by half a century of research. As an early advocate of an immature theory, Wegener was different. There were substantial differences of opinion about crustal mobility among scientists in the 1920s. By the 1970s, work such as Vine and Matthews’ study had brought consensus. Fifty years on, history has not vindicated Jeffreys, and it seems unlikely that it will vindicate those who reject the overwhelming evidence of anthropogenic climate change. ■ Naomi Oreskes is professor of the history of science at Harvard University in Cambridge, Massachusetts. e-mail: oreskes@fas.harvard.edu Frederick Vine and Drummond Matthews (1970). 1. Vine, F. J. & Matthews, D. H. Nature 199, 947–949 (1963). 2. Oreskes, N. The Rejection of Continental Drift: Theory and Method in American Earth Science (Oxford Univ. Press, 1999). 3. Dietz, R. S. Nature 190, 854–857 (1961). 4. Nye, M. J. Blackett: Physics, War, and Politics in the Twentieth Century (Harvard Univ. Press, 2004). 5. Oreskes, N. (ed.) Plate Tectonics: An Insider’s History of the Modern Theory of the Earth (Westview Press, 2001). 5 S E P T E M B E R 2 0 1 3 | VO L 5 0 1 | NAT U R E | 2 9 © 2013 Macmillan Publishers Limited. All rights reserved When Continental Drift Was Considered Pseudoscience | Science ... http://www.smithsonianmag.com/science-nature/when-continental-dr... 1 of 5 Alfred Wegener, in Greenland, c. 1930, was ridiculed as having “wandering pole plague.” (Alfred Wegener Institute, Germany) By Richard Conniff Smithsonian Magazine | Subscribe June 2012 Six seismologists and a civil servant, charged with manslaughter for failing to predict a 2009 earthquake that killed 308 people in the Apennine Mountain city of L’Aquila, in Italy, will serve six years in prison. The charge is remarkable partly because it assumes that scientists can now see not merely beneath the surface of the earth, but also into the future. What’s even more extraordinary, though, is that the prosecutors based their case on a scientific insight that was, not long ago, the object of open ridicule. [Editor's Note: The story was updated on October 22, 2012, to reflect the decision.] It was a century ago this spring that a little-known German meteorologist named Alfred Wegener proposed that the continents had once been massed together in a single supercontinent and then gradually drifted apart. He was, of course, right. Continental drift and the more recent science of plate tectonics are now the bedrock of modern geology, helping to answer vital questions like where to find precious oil and mineral deposits, and how to keep San Francisco upright. But in Wegener’s day, geological thinking stood firmly on a solid earth where continents and oceans 2/7/2017 2:18 PM When Continental Drift Was Considered Pseudoscience | Science ... http://www.smithsonianmag.com/science-nature/when-continental-dr... 2 of 5 were permanent features. We like to imagine that knowledge advances fact upon dispassionate fact to reveal precise and irrefutable truths. But there is hardly a better example of just how messy and emotional science can be than Wegener’s discovery of the vast, turbulent forces moving within the earth’s crust. As often happens when confronted with difficult new ideas, the establishment joined ranks and tore holes in his theories, mocked his evidence and maligned his character. It might have been the end of a lesser man, but as with the vicious battles over topics ranging from Darwinian evolution to climate change, the conflict ultimately worked to the benefit of scientific truth. The idea that smashed the old orthodoxy got its start on Christmas 1910, as Wegener (the W is pronounced like a V) browsed through a friend’s new atlas. Others before him had noticed that the Atlantic coast of Brazil looked as if it might once have been tucked up against West Africa, like a couple spooning in bed. But no one had made much of it, and Wegener was hardly the logical choice to show what they had been missing. He was a lecturer at Marburg University, not merely untenured but unsalaried, and his specialties were meteorology and astronomy, not geology. But Wegener was not timid about disciplinary boundaries, or much else. He was an Arctic explorer and a record-setting balloonist, and when his scientific mentor and future father-in-law advised him to be cautious in his theorizing, Wegener replied, “Why should we hesitate to toss the old views overboard?” He cut out maps of the continents, stretching them to show how they might have looked before the landscape crumpled up into mountain ridges. Then he fit them together on a globe, like jigsaw-puzzle pieces, to form the supercontinent he called Pangaea (joining the Greek words for “all” and “earth”). Next he assembled the evidence that plants and animals on opposite sides of the oceans were often strikingly similar: It wasn’t just that the marsupials in Australia and South America looked alike; so did the flatworms that parasitized them. Finally, he pointed out how layered geological formations often dropped off on one side of an ocean and picked up again on the other, as if someone had torn a newspaper page in two and yet you could read across the tear. Wegener called his idea “continental displacement” and presented it in a lecture to Frankfurt’s Geological Association early in 1912. The minutes of the meeting noted that there was “no discussion due to the advanced hour,” much as when Darwinian evolution made its debut. Wegener published his idea in an article that April to no great notice. Later, recovering from wounds he suffered while fighting for Germany during World War I, he developed his idea in a book, The Origin of Continents and Oceans, published in German in 1915. When it was published in English, in 1922, the intellectual fireworks exploded. Lingering anti-German sentiment no doubt intensified the attacks, but German geologists piled on, too, scorning what they called Wegener’s “delirious ravings” and other symptoms of “moving crust disease and wandering pole plague.” The British ridiculed him for distorting the continents to make them fit and, more damningly, for not describing a credible mechanism powerful enough to move continents. At a Royal Geographical Society meeting, an audience member thanked the speaker for having blown Wegener’s theory to bits—then thanked the absent “Professor Wegener for offering himself for the explosion.” But it was the Americans who came down hardest against continental drift. A paleontologist called it “Germanic pseudo-science” and accused Wegener of toying with the evidence to spin himself into “a state of auto-intoxication.” Wegener’s lack of geological credentials troubled another critic, who declared that it was “wrong for a stranger to the facts he handles to generalize from them.” 2/7/2017 2:18 PM When Continental Drift Was Considered Pseudoscience | Science ... http://www.smithsonianmag.com/science-nature/when-continental-dr... 3 of 5 He then produced his own cutout continents to demonstrate how awkwardly they fit together. It was geology’s equivalent of O.J. Simpson’s glove. The most poignant attack came from a father-son duo. Like Wegener, University of Chicago geologist Thomas C. Chamberlin had launched his career with an iconoclastic attack on establishment thinking. He went on to define a distinctly democratic and American way of doing science, according to historian Naomi Oreskes. Making the evidence fit grandiose theories was the fatal flaw in Old World science, Chamberlin said; the true scientist’s role was to lay out the facts and let all theories compete on equal terms. Like a parent with his children, he was “morally forbidden to fasten his affection unduly upon any one of them.” By the 1920s, Chamberlin was the dean of American science and his colleagues fawned that his originality put him on a par with Newton and Galileo. But he had also become besotted with his own theory of earth’s origins, which treated the oceans and continents as fixed features. This “great love affair” with his own work was characterized, historian Robert Dott writes, “by elaborate, rhetorical pirouetting with old and new evidence.” Chamberlin’s democratic ideals—or perhaps some more personal motivation—required grinding Wegener’s grandiose theorizing underfoot. Rollin T. Chamberlin, who was also a University of Chicago geologist, did his father’s dirty work: The drift theory “takes considerable liberties with our globe,” he wrote. It ignores “awkward, ugly facts” and “plays a game in which there are few restrictive rules.” Young Chamberlin also quoted an unnamed geologist’s remark that inadvertently revealed the heart of the problem: “If we are to believe Wegener’s hypothesis we must forget everything which has been learned in the last 70 years and start all over again.” Instead, geologists largely chose to forget Alfred Wegener, except to launch another flurry of attacks on his “fairy tale” theory in the middle of World War II. For decades afterward, older geologists warned newcomers that any hint of an interest in continental drift would doom their careers. Wegener took the assault as an opportunity to refine his ideas and address valid criticisms. When critics said he had not presented a plausible mechanism for the drift, he provided six of them (including one that foreshadowed the idea of plate tectonics). When they pointed out mistakes—his timeline for continental drift was far too short—he corrected himself in subsequent editions of his work. But he “never retracted anything,” says historian Mott Greene, author of an upcoming biography, Alfred Wegener’s Life and Scientific Work. “That was always his response: Just assert it again, even more strongly.” By the time Wegener published the final version of his theory, in 1929, he was certain it would sweep other theories aside and pull together all the accumulating evidence into a unifying vision of the earth’s history. (But even he would have been astonished by the charges against the Italians for failing to turn continental drift into a predictive device; that trial is expected to continue for months.) The turnabout on his theory came relatively quickly, in the mid-1960s, as older geologists died off and younger ones began to accumulate proof of seafloor spreading and vast tectonic plates grinding across one another deep within the earth. Wegener didn’t live to see it. Because of a subordinate’s failure, he and a colleague had to make a lifesaving delivery of food to two of his weather researchers spending the winter of 1930 deep in Greenland’s ice pack. The 250-mile return trip to the coast that November turned desperate. Wegener, at 50, yearned to be home with his wife and three daughters. He dreamed of “vacation trips with no mountain climbing or other semi-polar adventures” and of the day when “the 2/7/2017 2:18 PM obligation to be a hero ends, too.” But a quotation in his notes reminded him that no one accomplished anything worthwhile “except under one condition: I will accomplish it or die.” Somewhere along the way the two men vanished in the endless snow. Searchers later found Wegener’s body and reported that “his eyes were open, and the expression on his face was calm and peaceful, almost smiling.” It was as if he had foreseen his ultimate vindication. Extra Links for Writing Assignment 1, Geology 100 IN ADDITION TO THE PARTS OF THE TEXT REFERRED TO IN THE ASSIGNMENT, you might consider the following 'enrichment': Part 1. Hypothesis vs. Theory -- Continental Drift vs. Plate Tectonics    For starters, consider the following Smithsonian Magazine article from 2012, entitled When Continental Drift Was Considered Pseudoscience: http://www.smithsonianmag.com/science-nature/when-continental-drift-wasconsidered-pseudoscience-90353214/?all Here's a recent perspective from Naomi Oreskes, Nature Magazine, entitled How plate tectonics clicked: http://www.nature.com/news/earth-science-how-plate-tectonics-clicked-1.13655 - printed on the 50th anniversary of the publishing of the definitive article on sea-floor spreading, by Fred Vine. Please listen to the Podcast, if you'd like! Let's not forget Marie Tharp! Unfortunately, I didn't seriously learn about her until I heard a Bob Edwards interview of Hali Felt, who wrote her biography, entitled Soundings - a fascinating read. Here are a few links you may find useful: o Here's a link to a New York Times video summarizing Marie's obituary: http://nyti.ms/1cdkZlV o Here's a link to an hour-long talk by Hali Felt, at Columbia University: http://vimeo.com/53380314 and here's a link to a PDF of the PowerPoint used in the Hali Felt talk: http://online.geologyguy.com/pdfs/gebco_sixth_science_day_felt2.pdf o And here's a PDF of the obituary that started it all: http://online.geologyguy.com/pdfs/MarieTharp_NYT.pdf Part 2. Cascade Mountains (including Mt. St. Helens) -- an example of Andean Plate Boundary I have a special affinity for this volcano, since I had volcanic ash fall on my head some 550 miles to the east, at the edge of Yellowstone National Park (itself a “super” volcano!). That was Sunday evening, 18 May 1980, before most of you were born, I assume. I was driving back from a geology meeting in Utah, where I had listened to talks by USGS scientists describing the volcanic activity which had just begun two months earlier. I had not heard that the Mountain had erupted, because there was no radio reception along the way, through the mountains of Utah, Idaho, Wyoming and Montana. I was quite surprised when ash began to fall from the sky and show up in my headlights! The Google Earth image above shows how far the volcanic ash travelled in about 12 hours! The red triangles on the map are active volcanoes, and the yellow dots are earthquakes that occurred in the previous week. USGS Publication: Eruptions of Mount St. Helens: Past, Present, and Future: Link: http://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html th Links to several videos which will give you more of a feel for the power that was released on May 18 , 1980!  NOVA - Mt. St. Helens: Back From the Dead (not closed captioned, but a transcript is available in "Videos") http://www.pbs.org/wgbh/nova/earth/mt-st-helens.html the following are closed captioned, on my YouTube channel (you're welcome!)    Eruption of Mount St. Helens, 1980 (released in 1981) - http://youtu.be/Jn52OAPK8nI Mount St. Helens: May 18, 1980 (30th anniversary video) - http://youtu.be/_CrBp9KWY0o Mount St. Helens: A Catalyst for Change - http://youtu.be/6g927Z54E0Q This link will take you to the part of the USGS Volcanic Hazards Program website that summarizes the major types of volcanic hazards: http://volcanoes.usgs.gov/hazards/ Note the links to the main types of volcanic hazards:          Volcanic Gases Volcanic Gas and Climate Change Air Pollution SO2 Aerosols Lahars Pyroclastic Flows Volcanic Landslides Lava Flows Tephra Marie Tharp: Portrait of a Scientist Presented by Hali Felt, author of the book Soundings: The Remarkable Woman Who Mapped the Ocean Floor Image courtesy of the Library of Congress. Marie in the field with her father, William Tharp, a surveyor with the U.S. Soil Survey. Image courtesy of the Library of Congress. Marie on the streets of New York, shortly after she was hired to work at Dr. Maurice Ewing’s newly-formed Geophysical Institute at Columbia University. Image courtesy of Lamont-Doherty Earth Observatory. Bruce Heezen looking at a fathogram being produced by an early echo-sounder. Circa 1940s. Image courtesy of Lamont-Doherty Earth Observatory. Marie in her office at Columbia University’s Lamont Geological Observatory, pretending to work. Circa 1959. An explanation of Marie’s process from her first (and only) book. Co-authored with partner Bruce Heezen and Maurice Ewing. Published by the Geological Society of America in 1959 as The Floors of the Oceans: I. North Atlantic. Image from the Geological Society of America. The first six trans-Atlantic profiles. Marie used these to map the entire North Atlantic Ocean. Published in the Geological Society of America’s Special Paper #65—The Floors of the Oceans: I. North Atlantic. Image courtesy Marie Tharp Maps. A portion of Marie’s first published physiographic diagram, printed in 1957 and showing the Northeastern Atlantic Ocean floor. From the New York Times, 1 February 1957. The discovery of the world-wide rift valley was announced in 1957. In the article that accompanied these illustrations, the Times said that the Earth was being “pulled apart.” As a result, Lamont received letters from members of the public who feared for their safety. Image courtesy of the Library of Congress. Hand-painted globe used by Tharp and Heezen at presentations in the late 1950s and early 1960s. Heezen had such a globe with him in 1959 when he gave a talk about the newlydiscovered Mid-Atlantic Rift at Princeton University, causing Harry Hess to declare that Heezen had “shaken the foundations of geology.” Image courtesy of the Library of Congress. Jacques Cousteau in a two-man observation vessel aboard the Calypso. This photo was taken in 1959, when Cousteau docked his ship in New York for the First International Oceanographic Congress. At the IOC, he showed a film he’d taken of the Rift Valley while crossing the Atlantic; many previously skeptical scientists were convinced of the Rift’s existence. Marie discovers MidAtlantic Rift Valley MidAtlantic Rift Valley announced N. Atlantic physiographic diagram published 1957 1959 S. Atlantic physiographic diagram published Indian Ocean physiographic diagram published 1961 1964 Indian Ocean panorama published in National Geographic Magazine ________________________________________ 1952 1965 Marie Tharp’s Cartographic Contributions 1967 ___________________________________________ Seminal Papers in the History of Plate Tectonics Harry Hess publishes “History of the Ocean Basins” Bullard et al present “A Fit of the Continents Around the Atlantic” J.T. Wilson publishes “A New Class of Faults and Their Bearing on Continental Drift” W.J. Morgan presents “Rises, Trenches, and Great Crustal Faults” paper at AGU meeting Image courtesy Marie Tharp Maps. A portion of Marie’s second physiographic diagram; note the increased level of detail and appearance of fracture zones. Published by the Geological Society of America in 1961. Image from National Geographic Magazine. Marie and Bruce’s first collaboration with National Geographic Magazine and Heinrich Berann. Published as an insert to the magazine in October 1967, accompanying the article “Science Explores the Monsoon Sea.” Image courtesy Marie Tharp Maps. The 1977 World Ocean Floor Panorama, painted by Heinrich Berann and based on 25 years of Marie’s work. Questions to ponder: • Why didn’t the scientific community recognize that Marie’s maps made arguments for geological processes? • Why hasn’t Marie’s work been included in histories of the plate tectonics revolution? • How can scientists, the media, and the general public begin to have conversations about the ways in which maps make visual arguments? Geology 100, Phil Farquharson, presiding First Writing Assignment Fall 2017 (revised 12 September) First Five Chapters: Intro. to Geology, Plate Tectonics, Minerals, Igneous Activity, Volcanoes Essays (100 points total). Part 1. Explain thoroughly how it took 55 years (from 1915 until 1970) for the hypothesis of Continental Drift to develop into the theory of Plate Tectonics. READ THIS! - In other words, use the theory of Plate Tectonics to show how the Scientific Method was used to "flesh out" the hypothesis of Continental Drift put forth by Wegener, by adding new data provided by new technology and people until general buy-in was obtained in 1970, when the term "Plate Tectonics" was coined. (Chapter 1, especially 1.3, The Nature of Scientific Inquiry; and Chapter 2, especially 2.1 through 2.3, and 2.9, "Testing the Plate Tectonics Model"). Do not spend time discussing what came before 1915! Wegener did a great job of laying out the evidence he had available at the time. After your introductory paragraph, I do not expect to see the name "Wegener" again. Be sure to explain:      WHO were the key players? WHAT were the key observations and conclusions? WHERE were the observations made? WHEN were the key discoveries made? HOW were these discoveries accomplished, including fields of study, equipment, etc.? Your response should be no less than 500 words. (50 points) Part 2. Use plate tectonic theory to explain the origin of Mount St. Helens (and by extension, the Cascades and all Andean-type mountain ranges). In your answer, include a discussion of:      the plate tectonic process involved the origin of the magma and rocks the composition of the magma and rocks the type of eruptions that occur there other geologic features associated with Andean-type mountains. Your answer should be no less than 500 words. (50 points) For these questions, check the text and MasteringGeology Study Area (of course), and also study the links on the accompanying materials. It should go without saying that you should have successfully completed the Mastering Homework for the first five chapters. Important: know the meaning of the word PLAGIARISM - no plagiarism!
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