A Brief History of Geology Kieran D

Cambridge University Press 978-1-107-17618-8 — A Brief History of Geology Kieran D. O'Hara Frontmatter More Information

A Brief History of Geology

Geology as a science has a fascinating and controversial history. Kieran D. O’Hara’s book provides a brief and accessible account of the major events in the history of geology over the last 200 years – from early theories of Earth’s structure during the Reformation, through major controversies over the age of the Earth during the Industrial Revolution, to the more recent twentieth-century development of plate tectonic theory, and on to current ideas concerning the Anthropocene. Most chapters include a short feature box providing more technical and detailed elaborations on selected topics. The book also includes a history of the geology of the Moon, a topic not normally included in books on the history of geology. The book will appeal to students of Earth science, researchers in geology who wish to learn more about the history of their subject, and general readers interested in the history of science.

 . ’ is Professor Emeritus in the Department of Earth and Environmental Sciences at the University of Kentucky. He has published more than 40 articles in international journals and has received numerous research awards from the American National Sci- ence Foundation. He taught geology at undergraduate and graduate levels at the University of Kentucky for 30 years. His other books include Cave Art and Climate Change (2014) and Earth Resources and Environmental Impacts (2014).

‘O’Hara does a great job of covering both the old (late 1800s) and the new (1960-1970) history of geology. Included are informative, but concise, biographies of all the major players in the nineteenth and twentieth centuries. The author shows very clearly how Wegner’s continental drift – which was not originally accepted by the scientiﬁc community – came together with Harry Hess’sseaﬂoor spreading in the 1970s, and led to the “Great Plate Tectonic Revolution” in the Earth sciences. I really liked the chapter on isotopic dating, where the author clearly explains how geologists learned to use isotopes to date geologic events – no other book on the history of geology illustrates this so clearly.’ – Kent Condie, New Mexico Institute of Mining and Technology

‘The nearly four-century existence of geology as a concept –“the study of the Earth with its Furniture” as it was ﬁrst put – has been mired in periods of uncertainty, revolution, speculation and controversy. O’Hara has tied it all up in a concise, neatly arranged and highly readable summary, essential to all who want to know more of the fascinating story of this most fundamental of sciences.’ – Simon Winchester, author of The Map That Changed the World

A Brief History of Geology

 . ’ University of Kentucky

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First published 2018

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Library of Congress Cataloging-in-Publication Data Names: O’Hara, Kieran D., author. Title: A brief history of geology / by Kieran D. O’Hara. Description: Cambridge : Cambridge University Press, 2018. | Includes bibliographical references and index. Identiﬁers: LCCN 2017051822 | ISBN 9781107176188 (hardback : alk. paper) | ISBN 9781316628294 (pbk. : alk. paper) Subjects: LCSH: Geology–History. | Geologists–Biography. Classiﬁcation: LCC QE11 .O33 2018 | DDC 551.09–dc23 LC record available at https://lccn.loc.gov/2017051822

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Contents

Preface page ix

1 Major Nineteenth-Century Players 1 Introduction 1 Box 1.1 Extracts from Lyell’s Letters 2 Discussion 22 References 24

2 Toward a Geologic Time Scale 28 Introduction 28 The Phanerozoic 30 Radioactivity and Radiometric Dating 39 Dinosaur Extinction at the Cretaceous–Paleogene Boundary 45 Summary 48 References 49

3 A Vestige of a Beginning: The Age of the Earth 52 Introduction 52 Kelvin and the Second Law 53 Kelvin and the Age of the Earth 55 Age of the Oceans 57 Earth’s Sand Hourglass 61 Isotopic Ages 63 Box 3.1 Age of Meteorites and the Earth 67 References 69

4 The Origin of Igneous Rocks 71 The Neptunist–Plutonist Controversy 71 The Petrographic Microscope 77 v

vi 

Differentiation Mechanisms and Rock Classiﬁcation 80 Experimental Petrology 84 Origin of Granite 85 References 89

5 Tectonics in Crisis 91 Introduction 91 Early Models 92 Contraction Theory 96 Global Tectonics 98 Alpine Nappe Tectonics 101 Appalachian Fold and Thrust Belt 103 The Geosyncline Concept 107 Mylonites and the Elevation of Mountain Belts 109 Experimental Studies 111 Isostasy 112 References 115

6 Continental Drift 118 The Origin of Continents and Oceans 120 Box 6.1 Geophysicist Harold Jeffreys (1891–1989) 125 Wegener’s Supporters 127 Critics of Drift 132 Paleomagnetism 136 References 139

7 Plate Tectonics 141 Introduction 141 Ocean Floor Rifts 143 Transform Faults 149 Subduction Zones 151 The New Global Tectonics 151 Implications for Mountain Building 156

 vii

Implications for Igneous Activity and Tectonic Setting 158 Conclusions 161 References 163

8 Isotope and Trace Element Geology 166 Introduction 166 Mineral Ages 167 Whole Rock Ages 173 Stable Isotopes 177 Rare Earth Elements 180 References 183

9 Ice Ages and Ice Cores 185 Glacial Deposits 185 Deep Sea Cores 193 Ice Cores 200 References 208

10 Geology and Evolution of the Moon 211 Lunar Stratigraphy 212 Multi-Ringed Basins 214 The Apollo Program 216 The Highlands and the Magma Ocean Hypothesis 222 Mare Basalts 225 Origin of the Moon 227 References 230

11 Welcome to the Anthropocene: A Man-Made Epoch? 234 Introduction 234 Deﬁning the Anthropocene 235

Box 11.1 Annual CO2 Increase in the Atmosphere 241 The Anthropocene as an Archaeological Age? 243 References 244

viii 

12 The Structure of Geological Revolutions 247 Introduction 247 Catastrophism versus Lyell’s Uniformity Principle 249 Normal Science: The Geologic Stratigraphic Column 252 Crisis in Tectonics 253 First Response to Crisis: Continental Drift 257 Second Response to Crisis: Plate Tectonics 258 References 258

Index 260

Preface

Charles Lyell’s Principles of Geology (Vol. 1, 1830) is one of the earlier treatments of the history of geology, sketching progress throughout the history of geology. In that history, Lyell takes the Neptunist school to task for believing that all rock successions, including igneous rocks, were precipitations from a “chaotic fluid.” He also praised the English surveyor, William Smith, who by 1790 had recognized that stratified rock formations could be identified by their fossil assemblages and who, by himself, produced the first geologic map of England and Wales in 1815 – this work is recounted in Simon Winchester’s book The Map That Changed the World (2001). Subsequent histories of geology include Von Zittel’s History of Geology and Paleontology (1901), Archibald Geike’s The Founders of Geology (1905), and The Birth and Development of the Geological Sciences by Frank Adams (1938), which includes a chapter on ancient Greek and Roman writers. Geology in the Nineteenth Century by M. T. Greene (1982) focuses on tectonic theories, the origin of mountain belts, and Continental Drift. The Rejection of Continental Drift by Naomi Oreskes (1999) discusses the major players involved in the arguments on both sides of the Atlantic on this issue. The Ocean of Truth (1986) is a personal account by H. W. Menard of discoveries made in the oceans in the 1950s and 1960s leading up to, but prior to, the discovery of plate tectonics. A compilation of historically important academic papers on plate tectonics was produced by Alan Cox entitled Plate Tectonics and Geomagnetic Reversals (1973). The introduction by Cox sheds substantial light on the history of plate tectonics. This compilation also includes a 1944 paper by the British geologist Arthur Holmes, whose contribution to global tectonics has largely been underestimated. ix

x 

A series by H. R. Frankel entitled The Continental Drift Controversy was published in 2012 by Cambridge University Press and included four volumes: Volume 1, Wegener and the Early Debate; Volume 2, Paleomagnetism and Confirmation of Drift; Volume 3, Introduction of Seafloor Spreading; and Volume 4, Evolution into Plate Tectonics. Three important books by the historian and geologist Martin Rudwick published by Chicago University Press, are Earth’s Deep History (2014), Worlds before Adam (2008), and the Great Devonian Controversy (1985). Great Geologic Controversies by A. Hallam (1989) is also notable (Oxford University Press). Two Hundred Years of Geology in America, edited by C. J. Schneer (University Press of New England, 1979) confines itself to American geology. History of Geology by H. B. Woodward (Arno Press, 1978) confines itself to the seventeenth and eighteenth centuries. A History of Geology by G. Gohau (Rutgers University Press, 1991), translated from the French, takes a somewhat Eurocentric view of the history of geology. The present book begins in the 1780s with James Hutton and other founders of geology, and ends with the current proposal for an Anthropocene epoch, based on environmental considerations. I conclude the Anthropocene should be an archaeological subdivision rather than a geological one. Other topics are Continental Drift (Chapter 6) and the Pleistocene Ice Age (Chapter 9). Two topics not normally treated in a history of geology but included in this book are the history and origin of the Moon (Chapter 10) and a brief history of isotope geology (Chapter 8). A crisis in the subdiscipline of tectonics is identified in Chapter 5, beginning circa 1890s, and this crisis does not end until the discovery of plate tectonics in the 1960s (Chapter 7). The origin of igneous rocks is covered in Chapter 4. The final chapter attempts to examine whether the history of geology (not just that of plate tectonics) fits into the Kuhnian scientific revolution framework; I conclude that it does. Geologic jargon is kept to a minimum in the

 xi

hope that the book will be of interest not just to Earth science students and teachers, but also to a wider general audience. I would like to thank those who reviewed various chapters of the book: Steven Greb, Frank Ettensohn, David Moecher, Gustave Lester, Kent Ratajeski, Sean Bemis, and Malcom Rutherford.