Salisbury, Matthew H.

English

University of New Brunswick: Centre for Digital Scholarship Journals

Canada Rocks: TheGeologic Journey Nick Eyles and Andrew MiallFitzhenry and Whiteside, Ltd., Markham,ON, 2007.ISBN-1-55041-860-2Price: $60.00, Trade Paperback, 450 p.Reviewed by Matthew H. SalisburySenior Research ScientistGeological Survey of CanadaThere is a new book in the geologicalfirmament, a massive, readable, oftenentertaining tome on the geology ofCanada by Nick Eyles and AndrewMiall. Canada Rocks: The Geologic Journeypresents the complex and spectaculargeology of Canada as it evolved fromdistant orogenies in the Archean SlaveProvince to the last “terrane wreck” inthe Canadian Rockies. Although theauthors are distinguished academics,the book is designed to reach a muchwider audience, including the interestedpublic, undergraduate students andeven specialists who would benefitfrom a general overview of Canadiangeology. The authors clearly knowtheir trade: the audience is skilfullyengaged through the use of plain lan-guage and the generous use of full-colour photos, maps, drawings andeven paintings from the Group ofSeven. When yet another orogenycrumples the Maritimes, the spell isbroken with pop-up biographies ofCanadian heroes of geology or whim-sical geologic anecdotes such as “theQueen in camouflage”. There is pur-pose behind this casual style, however.Just about everything has happened toCanada: it has been torn apart, putback together, stretched, bombardedby meteorites, filed down by glaciers,drowned and eroded so many timesthat patterns emerge from repetition.By interpreting these patterns inCanada, the authors leave the readerwith a solid understanding of how theworld works as a whole.The overall organization ofthe book is well-designed to meet theseobjectives. The first three chapters laythe groundwork for a book of generalinterest by introducing the reader tothe early formation of the Earth andthe concept of deep time; the Earth’sinterior and the concept of plate tec-tonics; and finally, for future reference,a history in quick time of the evolutionof the continents with an emphasis onCanada. Then follows the core of thebook: five chapters arranged in orderof timing, on the great geologic eventswhich formed Canada: the formationand evolution of the shield; the drown-ing and draining of the shield; theaccretion of the Maritimes; the evolu-tion of Arctic geology; the accretion ofwestern Canada; and continental glacia-tion. The book concludes with chap-ters on Canada’s mineral and energywealth and environmental issues plus aglossary, index, references and timechart.While the book is well-designed and written, it suffers fromserious technical and scientific editingproblems. The first few chapters arerepetitious and confusing. For exam-ple, the evolution of the continentsfrom Arctica and Nena to now is care-fully developed in chapter three, thenrepeated all over again in chapter 4.The figures are one of the greatstrengths of the book but they are sonumerous that many are displaced farfrom their associated text. Many fig-ures are called or presented out oforder while others are not called at all,often making it difficult to track figuresand text. Adding to the confusion,some figures were orphaned from theirlegends when they were taken fromother sources, and a few are uninfor-mative, misleading or simply incorrect.Thrusting along the Grenville Front,for example, was from the southeast,not the northwest (Fig. 4.12) and fewgeophysicists would claim that subduc-tion extends directly to the core-mantleboundary (Fig. 2.4).More serious are numerouserrors in facts. Yes, the upper mantleis composed of peridotite, but thelower mantle is thought to be com-posed predominantly of perovkstiteand magnesiowusite. The density ofperidotite is closer to 3.3, not 2.3 g/ccand its compressional wave velocity is8, not 7 km/s. Seismic waves are not“electromechanical waves” and it ismisleading to liken the Earth to a giantnuclear reactor. Ultramafics are ser-pentinized, not basalts. The flat sur-face of the Cape Breton Highlands isno longer considered a peneplain cutto sea level. Seismic reflections arecaused by velocity-density contrasts,not chemical-density contrasts. Andon and on. In fairness, many of theseproblems occur in the first three chap-ters before the authors hit their strideand their specialties in the core of thebook. But to be fair to the reader, itwould have been better to have careful-ly read the book from beginning toend, to sort and edit the figures and tocorrect the text before rushing to pub-lish.Despite these problems,Canada Rocks is a wonderful book inmany ways. It is packed with informa-tion; it fills a broad popular niche andis truly a pleasure to read. My onlyserious recommendation is that nexttime, before the book goes to a secondprinting, as it deserves, it needs carefulscientific and technical editing; detailsavailable upon request.156

Canada Rocks: The Geologic Journey

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Canada Rocks: The Geologic Journey

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University of New Brunswick: Centre for Digital Scholarship Journals