Why Geology Matters

Why Geology Matters: Decoding the Past, Anticipating the Future

Doug Macdougall
Copyright Date: 2011
Edition: 1
Pages: 304
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  • Book Info
    Why Geology Matters
    Book Description:

    Volcanic dust, climate change, tsunamis, earthquakes—geoscience explores phenomena that profoundly affect our lives. But more than that, as Doug Macdougall makes clear, the science also provides important clues to the future of the planet. In an entertaining and accessibly written narrative, Macdougall gives an overview of Earth’s astonishing history based on information extracted from rocks, ice cores, and other natural archives. He explores such questions as: What is the risk of an asteroid striking Earth? Why does the temperature of the ocean millions of years ago matter today? How are efforts to predict earthquakes progressing? Macdougall also explains the legacy of greenhouse gases from Earth’s past and shows how that legacy shapes our understanding of today’s human-caused climate change. We find that geoscience in fact illuminates many of today’s most pressing issues—the availability of energy, access to fresh water, sustainable agriculture, maintaining biodiversity—and we discover how, by applying new technologies and ideas, we can use it to prepare for the future.

    eISBN: 978-0-520-94892-1
    Subjects: Geology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. List of Illustrations
    (pp. ix-x)
    (pp. xi-xiv)
    (pp. xv-xvi)
  6. CHAPTER ONE Set in Stone
    (pp. 1-20)

    In 1969, when I was a student in California, there was a rash of predictions from astrologers, clairvoyants, and evangelists that there would be a devastating earthquake and the entire state—or at least a large part of it—would fall into the ocean. The seers claimed this would happen during April, although they were not in agreement about the precise date. A few people took the news very seriously, sold their houses, and moved elsewhere. Others, a bit less cautious, simply sought out high ground on April 4, the date of the Big One according to several of the...

  7. CHAPTER TWO Building Our Planet
    (pp. 21-34)

    In 1969, the same year astrologists were predicting a big earthquake in California, another event was unfolding at the other end of the world that caught the attention of earth scientists. Its consequences were far-reaching. Japanese scientists working in Antarctica came across small, dark-colored rocks scattered across the surface of the ice. That might not seem unusual except that the scientists were working in a region that was completely blanketed in snow and ice; there was no obvious local source for the rocks. As it turned out, they were not from anywhere nearby—they had arrived from space. The rocks...

  8. CHAPTER THREE Close Encounters
    (pp. 35-62)

    Even though it has been known for centuries that meteorites—some of them quite large, like the Cape York meteorite mentioned in the previous chapter—periodically crash to Earth from space, the possibility that impact cratering is a potent geological force, affecting the physical, chemical, and biological evolution of our planet, has only been appreciated relatively recently. Earlier, most scientists who thought about the problem at all realized that the Earth must have been bombarded by space debris in the violent early days of its existence, but assumed that the significance of the process diminished rapidly after this initial onslaught....

  9. CHAPTER FOUR The First Two Billion Years
    (pp. 63-80)

    Several important events from the Earth’s history, such as the Moon-forming impact and the K-T mass extinction, have been discussed in earlier chapters, but here I’d like to begin a more systematic walk through our planet’s geological past, interspersed in later chapters with more detailed discussions of phenomena such as earthquakes and climate change. Space constraints mean that only selected highlights of the Earth’s history can be discussed. But I hope that this abbreviated treatment will provide a sense of our planet’s fascinating history, and how that history can inform us about the ways in which Earth processes operate. I...

  10. CHAPTER FIVE Wandering Plates
    (pp. 81-100)

    Before the 1960s geologists had some pretty bizarre ideas about how great mountain ranges like the Alps or the Andes formed. They were especially puzzled about the gigantic folds revealed by geological mapping in the Alps: thick layers of sedimentary rocks, originally deposited on the ocean floor but now thrust thousands of feet above sea level and looped over on themselves like a folded carpet. Unspecified “compressional forces” and vertical movements were evoked. Nobody could really say how these mysterious forces worked. Today, however, every geology student can tell you in great detail how plate tectonics is responsible for mountain...

  11. CHAPTER SIX Shaky Foundations
    (pp. 101-125)

    California is known for many things; one of them is earthquakes. It isn’t mentioned in tourist brochures or real estate promotions, but the state is home to about three-quarters of the entire estimated earthquake risk in the United States. With the advent of plate tectonics theory, it became clear why: a portion of the boundary between the Pacific and North American tectonic plates runs through the state. This particular part of the boundary is neither a subduction zone nor a spreading center, but a fault—the San Andreas Fault—along which the plates slide past each other (see figure 16)....

  12. CHAPTER SEVEN Mountains, Life, and the Big Chill
    (pp. 126-146)

    While reading the record of past earthquakes remains a tricky problem, the rock record is full of evidence about many other geological processes, even from very distant times in the past, as we have seen in earlier chapters. Here I will take up the journey through the Earth’s history begun in chapter 4, and explore what evidence from rocks has revealed about the Proterozoic eon, the two-billion-year stretch of time between the Archean and the Phanerozoic eons. Even though the Proterozoic includes what some earth scientists have called the “boring billion”—a period of time when, in some respects, not...

  13. CHAPTER EIGHT Cold Times
    (pp. 147-167)

    The ice ages near the end of the Proterozoic eon were undoubtedly the most severe glacial periods ever to affect our planet. But these frigid intervals happened so long ago that we know only their broad outlines and will never be able to fill in many of the fine details. We don’t know, for example, the exact configuration of the ice sheets, whether the glaciers waxed and waned repeatedly during the ice ages, how thick the ice was, or the extent of sea level fall and rise in response to glacier formation and melting. But we do know all this...

  14. CHAPTER NINE The Great Warming
    (pp. 168-187)

    In 1991 a paper in the journalNaturereported what the authors called “a remarkable oxygen and carbon isotope excursion … near the end of the Paleocene.” To anyone not familiar with the intricacies of paleoclimatology, this might sound like so much gobbledygook. You might also wonder why anyone should care. But the “isotope excursion” described in this paper, which was measured in deep-sea sediments dating from about 55 million years ago, signaled that global temperatures had increased dramatically and very suddenly at that time—and also that ocean circulation had undergone a radical reorganization. Not only that, the changes...

  15. CHAPTER TEN Reading LIPs
    (pp. 188-205)

    Scientists are fond of acronyms, the catchier the better; and geologists are no exception. The “PETM” of the previous chapter isn’t an especially inspired example, but in 1993 a group of geologists interested in a particular kind of volcanism came up with an acronym they thought would nicely describe the objects of their fascination: LIPs. They formed an international organization to study them, and they even feature a “LIP of the month” on their Web site. But these LIPs are not what someone stumbling across the Web site might think. In the geological context, the acronym stands forlarge igneous...

  16. CHAPTER ELEVEN Restless Giants
    (pp. 206-224)

    Until recently, the Aeta people on the Philippine island of Luzon, descendents of seminomadic hunter-gatherers, lived in small villages on the wooded slopes of Mount Pinatubo. Within the mountain, according to their beliefs, lived their supreme god, Apo Mallari. But in the spring of 1991, their god grew restless, and in June of that year Apo Mallari awoke fully, belching volcanic ash into the stratosphere in the second-largest volcanic eruption of the twentieth century. Fortunately, most of the Aeta had been evacuated or had simply fled before the worst of the eruption. For many, however, it meant permanent displacement. Their...

  17. CHAPTER TWELVE Swimming, Crawling, and Flying toward the Present
    (pp. 225-248)

    In 1818 Adam Sedgwick was named the Woodwardian Professor of Geology at the University of Cambridge in England. The chair had been endowed by a famous predecessor almost a century earlier, and the appointment was a great honor for Sedgwick. But he had no formal training in geology. Legend has it that he quipped, “Hitherto I have never turned a stone; henceforth I will leave no stone unturned.” Whether or not he really did utter those words, Sedgwick lived up to them. He became one of the nineteenth century’s foremost proponents of the relatively new science of geology, inspiring students...

  18. CHAPTER THIRTEEN Why Geology Matters
    (pp. 249-268)

    The preceding twelve chapters have, I hope, provided a window into the multifaceted world of earth science. The field got its start long before the wordgeologywas even coined, as a purely practical endeavor to locate and extract materials from the Earth for human use: chert and obsidian for cutting blades and weapons, hematite (iron ore) for early “crayons” and body paint pigment, clay for pottery, iron and copper for tools and ornaments. Today almost everything we use in our daily lives comes from the Earth, and geology plays a crucial role in feeding our voracious appetite for materials...

    (pp. 269-278)
  20. INDEX
    (pp. 279-286)
  21. Back Matter
    (pp. 287-288)