The declared aim of this book is to present 'snap-shots' of major tectonic and structural processes at specific times against which changing ideas on geotectonic behaviour may be tested. It has some success in this respect although some readers will question the choice of regions chosen for description. It is not intended to be the synthesis of crustal processes that its title seems to promise, nor does it in the event prove to be one. According to the editor most contributors were asked to provide a descriptive synthesis followed by speculations on the geotectonic processes operating, a major question being the applicability of plate tectonic models to Precambrian processes. But can the plate theory be defined tightly enough to allow the construction of tests that can overcome the inadequacy of the data available from old rocks? Under what circumstances can one actually rule out the application of plate theory?
The book begins and ends with chapters by the editor respectively on the first 600 million years of earth history (17pp) and on plate tectonics, past and present (48pp). Between them are 8 chapters which deal successively with the development of the Archaean Gneiss Corn lex of the North Atlantic region (Bridgwater, Collerson and Mayers, 51pp. and in fact main& concerned with Greenland), Barberton Mountain Land and the evolution of the primitive earth (Anhaeusser, 36pp. on the greenstone granite association), the Bushveld Complex (Hunter, 67pp), the Archaean crust of the Canadian Shield (Goodwin 44pp. and partly overlapping Chapter 2), the evolution of the atmosphere in the Precambrian (Eriksson and Truswell, 20pp.), the Proterzoic of the North Atlantic region (Sutton, 16pp., very generalised and relating mainly to Greenland, Scandinavia being mentioned merely in passing), the Caledonian-Iapetus Ocean (Roberts and Gale, 88pp., Newfoundland to Svalbard) and European plate movements during the Carboniferous (Johnson, 18pp).
Only Chapter 2 contains photographs (none the worse for being former acquaintances). No cross-referencing between articles was discovered, even in the editor's own chapters. There is no evidence that contributors saw one another's articles before publication. The long, informative and well-argued chapter on the Caledonian-Iapetus Ocean, subject matter most familiar to the reviewer, is illustrated by a number of maps at various scales up from about 1 to 700,000. Unfortunately the smallest-scale map of any component of the assemblage, that of Scandinavia at about 1 to 16 million, is a disap ointment. The chapter deals within Scandinavia most extensively with areas well-known to tge authors but only briefly with the rest. Yet is it not one of the advantages of writing syntheses that the unfamiliar is tested against the familiar? Finally the reviewer feels it necessary to urge caution until proof appears of the acceptance (pp. 293, 317) in west Norway of a Cambrian-Arenig succession. In fact up to the time of writing this review sequences unconformably below Ashgill strata have yielded neither fossils nor useful radiometric ages (a note added in proof to this chapter states that it was completed near the end of 1975).
The book by its very nature cannot be co-ordinated attack on the major geotectonic problems of the pre-Mesozoic. Nor is it a review of the applicability of plate tectonics to the period. In spite of the editor's interesting attempts at beginning and end to give it shape the whole is less a book than a collection of individually interesting and well-written papers.