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.