DOCSLIB.ORG

Arthur Holmes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Arthur Holmes Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 FOREWORD Arthur Holmes by FREDERICK HENRY STEWART T H I s V O L U M E is dedicated to Professor ARTHUR HOLMES, a man to whom Earth scientists, whether geochronologically inclined or not, look as one of the great geologists of the century. Those of us fortunate enough to know Holmes personally find him a quiet man of extraordinary charm, willing to take enormous trouble to help lesser mortals with their problems. All of us know him as a man of brilliant ideas. He has exercised a profound influence on almost all branches of geology, not only through his own remarkable researches but also by his beautifully written textbooks (on which many of us were weaned) and his stimulation of the research qualities of his students--first in Durham University, where he built up a new department from scratch, and later in Edinburgh University, which was honoured with his occupation of the Chair of Geology for thirteen years and with his presence as Emeritus Professor for six years after he retired in I956. Holmes has made a great number of contributions to our knowledge of the geology of many parts of the world, from his home district in the north of England to Africa, India, and elsewhere, but the descriptive aspect of his work has been, far more than with most men, merely a prelude to his remarkable studies of the wider genetic problems of our science. He has gone deep into the major questions of the origin of igneous rocks, partly in association with his accomplished and eminent wife, Dr Doris Reynolds. He was never a man to shun controversy or to be trammelled by tradition, and his work on the origin of the alkaline rocks of Africa and elsewhere, on the thorny problems of granites and their associates, on the origin and development of magmas, and on the role of metasomafism in rock genesis has broadened the vision of igneous and metamorphic petrologists all over the world. His contributions on the geophysical aspects of geology are classic: the nature of orogenic and epeirogenic activity, movements in the Earth's mantle, con- tinental drift, radioactivity in geology--one could go on for a long time listing the aspects of geology to which he has made major contributions. In fact there is hardly a main branch of the subject, other than palaeontology, with which his name is not associated. And undoubtedly one of his greatest gifts to science has been his work on geological time. Holmes was born at Hebburn, near Newcastle upon Tyne, in I89O, six years before the discovery of radioactivity by Becquerel, at a time when the ages of rocks and of the Earth were being hotly debated by geologists and physicists with no apparent prospect of agreement. By I897 Kelvin, from heat-flow considerations, had reduced the time since the Earth's consolidation to between 20 and 4 ° million years. Many geologists requiied much more time for the formation of immensely thick sedimentary successions by processes similar to those of the present day, and Joly and Geikie arrived at figures of the order of I oo million years or more, while Quart. 37. geol. Soc. Lond. vol. I2o s, I964, pp. 3-I I, frontispiece. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 F. H. Stewart Goodchild estimated 704 million years from the base of the Cambrian. It was some time before it became apparent from Strutt's work that the Earth's supply of heat from radioactivity made nonsense of the estimates of the physicists, and before it was realized by Rutherford, in 19o3, that radioactivity might provide a means for determining the age of minerals in terms of millions of years. During his schooldays Holmes's inquiring mind had questioned the magic date for the Creation, 4OO4B.C., in Archbishop Ussher's chronology for the book of Genesis, and in the sixth form his interest in geology was awakened by an enlightened schoolmaster who encouraged him to read Kelvin and Suess. As an undergraduate of Imperial College he began more formal studies in 19o7, the year in which Boltwood calculated approximate ages of a number of uranium-bearing minerals from lead ratios. After work in the laboratory of Strutt, whose studies of helium in minerals gave results consistent with those of Boltwood, Holmes published his first paper in 1911 in the Proceedings of the Royal Society: 'The association of lcad with uranium in rock-minerals, and its application to the measurement of geological time'. In this work he gave estimates of ages of minerals which did not at all please some of the older geologists of the time, but which, considering the state of knowledge of radio- active phenomena at that time, were remarkably close to those now accepted. Since that first paper, Holmes has published more than fifty contributions on the subject of radiometric age, ranging from works on the end-product of thorium, the distribution of radium, and the radioactivity of potassium, to Pre-Cambrian and post-Cambrian time-scales and the age of the Earth. In 1947 he gave us a Phanero- zoic time-scale which was the Bible of geologists for a long time. The post-war explosion of work on age, with the appearance of new methods, led to his revision of this time-scale in 1959, and he wrote at that time (Holmes 1959, p. 184) : 'The revised time-scale.., will also require revision in its turn, since each year the dated control points become more numerous, more precisely fixed, and less unevenly distributed through the geological column'. That is the object of this volume, and we hope that it and future revisions may not bc too unworthy for dedication to a man who was aptly described by one of the speakers at the symposium as the 'genius in the business'. [Professor] F. H. Stewart, PH.D.F.R.S.F.R..~.E.F.G.S. Grant Instituteof Geology, West Mains Road, Edinburgh 9 ARTHUR HOLMES, D.SC. A.R.C.S.M.R.I.A. LL.D.F.R.S.E.F.R.S.F.G.S. Born 14 January I89O , at Hebburn-on-Tyne; Imperial College, London, 19o7-I o; expedition to Mozambique, I9I I ; Demonstrator in Geology, Imperial College, 1912-2o; Chief Geologist, Yomah Oil Co., Burma, 192o-3; Reader and Professor of Geology, Durham Colleges, University of Durham, 1924-43; Regius Professor of Geology, University of Edinburgh, I943-56, Professor Emeritus since I956; Exchange Professor, University of Basle, 1930; Lowell Lecturer, Harvard Univer- sity, 1932; Foreign Honorary Member American Academy of Arts and Sciences, 1934; Correspondent Geological Society of America, 1936; Honorary Member Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Foreword: Arthur Holmes Royal Geological Society of Cornwall, x937; Corresponding Member Geological Society of Belgium, i946 , Honorary Member, 1956; Honorary Member Belgian Society of Geology, Palaeontology, and Hydrology, 1947; Foreign Member Royal Swedish Academy of Sciences, 1947; Foreign Member Royal Netherlands Academy of Sciences, 1947; Foreign Member Geological Society of Stockholm, 1952; Foreign Member Academy of Sciences, Institute of France, 1955; Murehison Medal, Geological Society of London, x94o, Wollaston Medal, I956; Penrose Medal, Geological Society of America, 1956; Fourmarier Medal, Royal Academy of Belgium, 1957; Fellow of Imperial College, I959; Hon. LL.D., Edinburgh, x960; Vetlesen Prize, 1964. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Works by Arthur Holmes [Within any one year, items have been arranged in the following sequence: books; original papers; book reviews, etc. Works of joint authorship are placed at the end of the items for each year.] HOLmeS, A. 191 i. The association of lead with uranium in rock-minerals, and its application to the measurement of geological time. Proc. roy. Soc. (A), 85, 248--56. I91 I. The duration of geological time. Nature, Lond. 87, 9-1o. & WRAY, D. A. 1912. Outlines of the geology of Mozambique. Geol. Mag. (5) 9, 412-7 • -- & ~ 1913. Mozambique: a geographical study. Geogr. 07. 42, 143-52. 1913. The age of the Earth. London & New York (Harper). xii+ I96 pp. 1913. Radium and the evolution of the Earth's crust. Nature, Lond. 9 x, 398. -- 1914. Lead and the final product of thorium. Nature, Lond. 93, lO9. 1914 . The terrestrial distribution of radium. Sci. Progr. 9, 12-46. 1914. The lateritic deposits of Mozambique. Geol. Mag. (6) z, 529-37. & LAWSON, R. W. 1914. Lead and the end product of thorium. (Part I). Phil. Mag. (6) 28, 823-4 ° . i915. Radio-activity and the measurement of geological time. Proc. Geol. Ass., Lond. 26, 289- 309. 1915. Radio-activity and the Earth's thermal history. Part I. The concentration of the radio- active elements in the Earth's crust. Geol. Mag. (6) 2, 6o-7 I. 1915. Radio-activity and the Earth's thermal history. Part II. Radio-activity and the Earth as a cooling body. Geol. Mag. (6) 2, IO2-I2. -- 19I 5. A contribution to the petrology of north-western Angola. Geol. Mag. (6) 2, 228-32; 267-72; 322--8; 366-7o. & LAWSON, R. W. 1915. Lead and the end product of thorium. (Part II). Phil. Mag. (6) ~'9, 673-88. 1916. Radio-activity and geology. [Book review] Geol. Mag. (6) 3, 176-8. -- 19 I6. Contribution to the discussion on radio-active evidence of the age of the Earth. Rep. Brit. Ass. 1915, 432-4. --- 1916. Radio-activity and the Earth's thermal history. Part III. Radio-activlty and isostasy. Geol. Mag.
Load more

Recommended publications
  • PDF— Granite-Greenstone Belts Separated by Porcupine-Destor
    C G E S NT N A ER S e B EC w o TIO ok N Vol. 8, No. 10 October 1998 es st t or INSIDE Rel e • 1999 Section Meetings ea GSA TODAY Rocky Mountain, p. 25 ses North-Central, p. 27 A Publication of the Geological Society of America • Honorary Fellows, p. 8 Lithoprobe Leads to New Perspectives on 70˚ -140˚ 70˚ Continental Evolution -40˚ Ron M. Clowes, Lithoprobe, University -120˚ of British Columbia, 6339 Stores Road, -60˚ -100˚ -80˚ Vancouver, BC V6T 1Z4, Canada, 60˚ Wopmay 60˚ [email protected] Slave SNORCLE Fred A. Cook, Department of Geology & Thelon Rae Geophysics, University of Calgary, Calgary, Nain Province AB T2N 1N4, Canada 50˚ ECSOOT John N. Ludden, Centre de Recherches Hearne Pétrographiques et Géochimiques, Taltson Vandoeuvre-les-Nancy, Cedex, France AB Trans-Hudson Orogen SC THOT LE WS Superior Province ABSTRACT Cordillera AG Lithoprobe, Canada’s national earth KSZ o MRS 40 40 science research project, was established o Grenville Province in 1984 to develop a comprehensive Wyoming Penokean GL -60˚ understanding of the evolution of the -120˚ Yavapai Province Orogen Appalachians northern North American continent. With rocks representing 4 b.y. of Earth -100˚ -80˚ history, the Canadian landmass and off- Phanerozoic Proterozoic Archean shore margins provide an exceptional 200 Ma - present 1100 Ma 3200 - 2650 Ma opportunity to gain new perspectives on continental evolution. Lithoprobe’s 470 - 275 Ma 1300 - 1000 Ma 3400 - 2600 Ma 10 study areas span the country and 1800 - 1600 Ma 3800 - 2800 Ma geological time. A pan-Lithoprobe syn- 1900 - 1800 Ma 4000 - 2500 Ma thesis will bring the project to a formal conclusion in 2003.
    [Show full text]
  • Geology and Geomorphology of the Urema Graben with Emphasis on the Evolution of Lake Urema
    Journal of African Earth Sciences 58 (2010) 272–284 Contents lists available at ScienceDirect Journal of African Earth Sciences journal homepage: www.elsevier.com/locate/jafrearsci Geology and geomorphology of the Urema Graben with emphasis on the evolution of Lake Urema Franziska Steinbruch * Scientific Services of Gorongosa National Park, Avenida do Poder Popular 264, Beira, Mozambique article info abstract Article history: The Lake Urema floodplain belongs to the Urema Catchment and is located in the downstream area of the Received 19 December 2008 Pungwe River basin in Central Mozambique. The floodplain is situated in the Urema Graben, which is the Received in revised form 8 February 2010 southern part of the East African Rift System. Little geological information exists about this area. The cir- Accepted 12 March 2010 culated information is not readily available, and is often controversial and incomplete. In this paper the Available online 20 March 2010 state of knowledge about the geology and tectonic evolution of the Lake Urema wetland area and the Urema Catchment is compiled, reviewed and updated. This review is intended to be a starting point Keywords: for approaching practical questions such as: How deep is the Urema Graben? What controls the hydrol- East African Rift System ogy of Lake Urema? Where are the hydrogeological boundaries? Where are the recharge areas of the Lake Floodplain Hydrogeology Urema floodplain? From there information gaps and needs for further research are identified. Lake Urema Ó 2010 Elsevier Ltd. All rights reserved. Mozambique 1. Introduction 2. Regional geology and tectonic evolution The Lake Urema floodplain belongs to the Urema Catchment 2.1.
    [Show full text]
  • Geophysical Journal International
    Geophysical Journal International Geophys. J. Int. (2016) 204, 1565–1578 doi: 10.1093/gji/ggv538 GJI Seismology Ambient noise tomography of the East African Rift in Mozambique Ana Domingues,1,2,∗ Grac¸a Silveira,3,4 Ana M.G. Ferreira,5,6 Sung-Joon Chang,7 Susana Custodio´ 3 and Joao˜ F.B.D. Fonseca1 1Laboratorio´ de Sismologia, 6o, Piso do Complexo Interdisciplinar, Instituto Superior Tecnico,´ Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal. E-mail: [email protected] 2Department of Earth and Planetary Sciences, Birkbeck, University of London, London WC1E 7HX, United Kingdom 3Instituto Dom Luiz, Faculdade de Ciencias,ˆ Universidade de Lisboa, Campo Grande, Ed. C8,Piso3,Gab.5 (8.3.05) 1749-016 Lisbon, Portugal 4Instituto Superior de Engenharia de Lisboa—ISEL, Rua Conselheiro Em´ıdio Navarro, 1, 1959-007 Lisbon, Portugal 5Department of Earth Sciences, University College London, London WC1E 6BT, United Kingdom 6CEris, ICIST, Instituto Superior Tecnico,´ Universidade de Lisboa, Lisbon, Portugal 7Division of Geology and Geophysics, Kangwon National University, Chuncheon, Gangwon-do 24341, South Korea Downloaded from Accepted 2015 December 15. Received 2015 November 8; in original form 2015 May 19 SUMMARY Seismic ambient noise tomography is applied to central and southern Mozambique, located in http://gji.oxfordjournals.org/ the tip of the East African Rift (EAR). The deployment of MOZART seismic network, with a total of 30 broad-band stations continuously recording for 26 months, allowed us to carry out the first tomographic study of the crust under this region, which until now remained largely unexplored at this scale. From cross-correlations extracted from coherent noise we obtained Rayleigh wave group velocity dispersion curves for the period range 5–40 s.
    [Show full text]
  • When the Earth Moves Seafloor Spreading and Plate Tectonics
    This article was published in 1999 and has not been updated or revised. BEYONDBEYOND DISCOVERYDISCOVERYTM THE PATH FROM RESEARCH TO HUMAN BENEFIT WHEN THE EARTH MOVES SEAFLOOR SPREADING AND PLATE TECTONICS arly on the morning of Wednesday, April 18, the fault had moved, spanning nearly 300 miles, from 1906, people in a 700-mile stretch of the West San Juan Bautista in San Benito County to the south E Coast of the United States—from Coos Bay, of San Francisco to the Upper Mattole River in Oregon, to Los Angeles, California—were wakened by Humboldt County to the north, as well as westward the ground shaking. But in San Francisco the ground some distance out to sea. The scale of this movement did more than shake. A police officer on patrol in the was unheard of. The explanation would take some six city’s produce district heard a low rumble and saw the decades to emerge, coming only with the advent of the street undulate in front of him, “as if the waves of the theory of plate tectonics. ocean were coming toward me, billowing as they came.” One of the great achievements of modern science, Although the Richter Scale of magnitude was not plate tectonics describes the surface of Earth as being devised until 1935, scientists have since estimated that divided into huge plates whose slow movements carry the the 1906 San Francisco earthquake would have had a continents on a slow drift around the globe. Where the 7.8 Richter reading. Later that morning the disaster plates come in contact with one another, they may cause of crushed and crumbled buildings was compounded by catastrophic events, such as volcanic eruptions and earth- fires that broke out all over the shattered city.
    [Show full text]
  • Th E Age of the Earth
    EDITORIAL TH E AGE OF THE EARTH PRINCIPAL EDITORS JAMES I. DREVER, University of Wyoming, USA ([email protected]) The “Age of the Earth” is of 200 students, “Have you had a discussion with GEORGES CALAS, IMPMC, France one of the most common someone who thinks the Earth is much younger ([email protected]) JOHN W. VALLEY, University of Wisconsin, USA titles in the geological than 4500 million years?”, and about 50% say ([email protected]) literature, and with good “yes.” I then have 50 minutes to talk about how PATRICIA M. DOVE, Virginia Tech ([email protected]) reason. The scientific rocks are dated and to compare 4500 Ma with ADVISORY BOARD 2012 and philosophical impli- earlier estimates. I explain that geochronology is JOHN BRODHOLT, University College London, UK cations are immense. based on observable data and that the hypotheses NORBERT CLAUER, CNRS/UdS, Université de Strasbourg, France This issue of Elements is are testable, and I encourage students to at least WILL P. GATES, SmecTech Research Consulting, devoted to measuring look through the windows of clean-labs to see Australia th GEORGE E. HARLOW, American Museum geologic time on the 100 people running mass spectrometers. The serious of Natural History, USA John Valley anniversary of a book students may read this issue of Elements and get JANUSZ JANECZEK, University of Silesia, Poland HANS KEPPLER, Bayerisches Geoinstitut, with this title (Holmes an appreciation for the depth and complexity of Germany 1913). The book is a good read—a clear historical determining age, but no fi rst-year student, and DAVID R.
    [Show full text]
  • Parting Shots
    PARTING SHOTS A RECORD BRIMFUL OF PROMISE Arthur Holmes is mentioned in several articles tifi c work at what we now call Imperial College, in this issue, by John Valley in his editorial, in London, and Cherry Lewis gives a detailed by Condon and Schmitz in their introductory account of his troubled work with the minerals article, and by Mattinson in his review of the industry in Mozambique and the petroleum U–Pb method. Google ‘Arthur Holmes’ and industry in Burma. His main academic career you will fi nd a lot of articles about his scien- began in 1924 when he was given the job of tifi c work, and there is a very readable biog- starting a department of geology at Durham raphy by Cherry Lewis which strikes a nice University, where 40 years later I obtained both balance between his scientifi c and personal my degrees. The student geological society in life. There is no question that he was a giant Durham is still called ‘The Arthur Holmes of 20th-century Earth science. The U–Pb age of Geological Society’. In 1943 he took up the 370 Ma that he obtained for accessory minerals Chair of Geology at Edinburgh where I’m Diagrammatic section across the “FIGURE 744: separated from a nepheline syenite from the writing now. I pass his picture every time I Andesite Line and a typical island arc Christiania region of Norway (Holmes 1911) is go up the main stairs in the Grant Institute (e.g. Japan or Kamchatka) to illustrate a speculative arrangement of convection currents which might a milestone not just for geology but for other (my fi rst picture).
    [Show full text]
  • I5 Wegener's Geological Evidence for Pangea < Holmes >
    WEGENER AND CONTINENTAL DRIFT 493 i5 Wegener’s geological evidence for Pangea < Holmes > The term Pangea (or Pangaea) comes from the Greek ‘pan’=all, entire + ‘gaea’=land, Earth. The name is frequently stated to have been coined by Alfred Wegener (1914) in Die Entstehung der Kontinente und Ozeane (The Origin of the Continents and Oceans), but it has not been found in the 1st edition of that book.—Georoots.1 The first use of the word [Pangea] comes in a 1924 translation of Wagener’s book, by the man named Skerl.—Winchester.2 And in fact the word is used in Wegener’s book but not as a proper noun (and so it cannot be found in the book’s index) in the sentence ‘Schon die Pangäa [the pangæa] der Karbonzeit hatte so einen Vorderrand (Amerika) ...’ once in the 1920 edition, p. 120, and again so once in the 1922 edition, p. 131. Pangea is first used as a proper noun by J. W. Evans in his introduction to the 1924 book.—HR. The geological evidence that Wegener marshaled to support his reconstruction of a primordial continent (Pangea) was vast in scope. A deduction would be that fossils of closely related land animals and plants should be now separated by wide oceans if Pangea had existed. Wegener, at first, was not able to give examples and this could be construed to negate the once existence of Pangea. But later, Wegener did find some examples and Arthur Holmes favorably observed: “Negative evidence may be destroyed at any moment by fresh discoveries, whereas genuine positive evidence can never be explained away.” 3 However, landbridges could be evoked to explain the fossil data.
    [Show full text]
  • The Historical Background
    01 orestes part 1 10/24/01 3:40 PM Page 1 Part I The Historical Background The idea that continents move was first seriously considered in the early 20th century, but it took scientists 40 years to decide that it was true. Part I describes the historical background to this question: how scientists first pondered the question of crustal mobility, why they rejected the idea the first time around, and how they ultimately came back to it with new evidence, new ideas, and a global model of how it works. 01 orestes part 1 10/24/01 3:40 PM Page 2 01 orestes part 1 10/24/01 3:40 PM Page 3 Chapter 1 From Continental Drift to Plate Tectonics Naomi Oreskes Since the 16th century, cartographers have noticed the jigsaw-puzzle fit of the continental edges.1 Since the 19th century, geol- ogists have known that some fossil plants and animals are extraordinar- ily similar across the globe, and some sequences of rock formations in distant continents are also strikingly alike. At the turn of the 20th cen- tury, Austrian geologist Eduard Suess proposed the theory of Gond- wanaland to account for these similarities: that a giant supercontinent had once covered much or all of Earth’s surface before breaking apart to form continents and ocean basins. A few years later, German meteo- rologist Alfred Wegener suggested an alternative explanation: conti- nental drift. The paleontological patterns and jigsaw-puzzle fit could be explained if the continents had migrated across the earth’s surface, sometimes joining together, sometimes breaking apart.
    [Show full text]
  • Conference to Celebrate the Centenary of the First Female Fellows of the Geological Society London
    Conference to Celebrate the Centenary of the First Female Fellows of the Geological Society London May 21st 2019 Organised by Geological Society London: History of Geology Group A Conference to Celebrate the Centenary of the First Female Fellows of the Geological Society London May 21st 2019 Organised by the Geological Society London: History of Geology Group Welcome to the conference! We are celebrating 100 years to the day since the admission of the first female Fellows of the Geological Society - 21st May 1919. Conference Convenors: Prof. Cynthia Burek University of Chester [email protected] Dr. Bettie Higgs, University College Cork b.higgs@ucc,ie Cover photos: (from left to right) Sedgwick Club with Gertrude Elles, Margaret Crosfield, Ethel Skeat and Ethel Wood; Individual photographs of Maria Ogilvie Gordon; Gertrude Elles; Catherine Raisin; Margaret Crosfield on a Geologists’ Association fieldtrip to Leith Hill 1912. SUMMARY CONFERENCE SCHEDULE 9.00-9.55 am Registration Session 1: Chair Prof. Cynthia Burek 9.55-10.00 Welcome and Introduction 10.00-10.50 Keynote Speaker: World War I through Affirmation Action — Women in Petroleum Geology Make a Difference Robbie Gries 10.50-11.10 Janet Watson: First female President of the Geological Society Glynda Easterbrook 11.10-11.30 Coffee and Posters (see poster abstracts) Session 2: Chair Dr. Bettie Higgs 11.30-11.50 Margaret Chorley Crosfield FGS: The very first female Fellow of the Geological Society Cynthia Burek 11.50-12.10 Maria Graham and the Geological Society Carl Thompson 12.10-12.30
    [Show full text]
  • Artificial Groundwater Recharge – Is It Possible in Mozambique?
    Artificial groundwater recharge – is it possible in Mozambique? Johanna Alexson Dissertations in Geology at Lund University, Bachelor’s thesis, no. 369 (15 hp/ECTS credits) Department of Geology Lund University 2013 Artificial groundwater recharge – is it possible in Mozambique? Bachelor’s thesis Johanna Alexson Department of Geology Lund University 2013 Contents 1 Introduction ......................................................................................................................................................... 5 2 Method ................................................................................................................................................................. 5 3 Artificial recharge systems and their purpose .................................................................................................. 5 3.1 Different purposes 5 3.2 Artificial recharge systems 5 4 Requirements ...................................................................................................................................................... 7 4.1 Experience 7 4.2 Sediment properties and problems 7 4.2.1 Soil 7 4.2.2 Clogging 8 4.3 Surface- and groundwater chemistry and availability 8 4.3.1 Water chemistry 8 4.3.2 Surface water chemistry 10 4.3.3 Groundwater chemistry 10 4.3.4 Availability 10 4.4 Water improvement options 10 4.4.1 Oxidation 10 4.4.2 Disinfection 10 4.4.3 Corrosion correction 11 5. Conditions of Mozambique ............................................................................................................................
    [Show full text]
  • GSA TODAY North-Central, P
    Vol. 9, No. 10 October 1999 INSIDE • 1999 Honorary Fellows, p. 16 • Awards Nominations, p. 18, 20 • 2000 Section Meetings GSA TODAY North-Central, p. 27 A Publication of the Geological Society of America Rocky Mountain, p. 28 Cordilleran, p. 30 Refining Rodinia: Geologic Evidence for the Australia–Western U.S. connection in the Proterozoic Karl E. Karlstrom, [email protected], Stephen S. Harlan*, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131 Michael L. Williams, Department of Geosciences, University of Massachusetts, Amherst, MA, 01003-5820, [email protected] James McLelland, Department of Geology, Colgate University, Hamilton, NY 13346, [email protected] John W. Geissman, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, [email protected] Karl-Inge Åhäll, Earth Sciences Centre, Göteborg University, Box 460, SE-405 30 Göteborg, Sweden, [email protected] ABSTRACT BALTICA Prior to the Grenvillian continent- continent collision at about 1.0 Ga, the southern margin of Laurentia was a long-lived convergent margin that SWEAT TRANSSCANDINAVIAN extended from Greenland to southern W. GOTHIAM California. The truncation of these 1.8–1.0 Ga orogenic belts in southwest- ern and northeastern Laurentia suggests KETILIDEAN that they once extended farther. We propose that Australia contains the con- tinuation of these belts to the southwest LABRADORIAN and that Baltica was the continuation to the northeast. The combined orogenic LAURENTIA system was comparable in
    [Show full text]
  • Arthur Holmes with Maggie, Born
    RROCKOCK STARS STARS great synthesis, The Face of the Earth, had recently been trans- lated into English. Holmes later remarked how the inspirational Mr. McIntosh and these two works were largely responsible for the direction his life took, for it was at school that his interests in physics and geology were Arthur Holmes with Maggie, born. At 17, he won a scholar- his first wife, and Geoffrey, his ship to study physics at the Royal second son, in Durham, ca. 1930. College of Science (later Imperial College) in London where, in his second year, he took a course in geology. Against the advice of his physics tutors, he decided to become a geologist. Radioactivity had been discovered in 1896 and was causing much excitement. By 1904, Ernest Rutherford had determined the first radiometric date, utilizing the discovery that helium was gen- erated in the decay process. Unfortunately, owing to the problem of helium leakage, these early dates were only minimum values, so Holmes decided to combine his interest in physics and geol- ogy in the search for an alternative technique. Building on Bertram Boltwood’s work, which indicated that lead might be the Arthur Holmes as a young man in his early 20s. This photo was final decay product of uranium, Holmes performed the very first probably taken in 1912 when Holmes joined the Geological Society uranium-lead analysis specifically determined for age-dating pur- of London. poses. It yielded 370 Ma for a Devonian rock. Aged only 21, he had embarked on his lifetime’s quest “to graduate the geological column with an ever-increasingly accurate time scale.” In April Arthur Holmes: 1911, the paper was read to members of the Royal Society while An Ingenious Geoscientist Holmes was in Mozambique.
    [Show full text]