This benchmark book and accompanying 1:25000 map of the classic Glen Coe area by Peter Kokelaar and Ian Moore are of the highest quality. The excellent text is lavishly illustrated with colour maps, delightful diagrams and spectacular annotated colour photographs. The large-scale map contains a wealth of new data and has sufficiently clear topographic information to permit users to locate themselves accurately. David Stephenson has contributed to both the text and the map and provided his usual outstanding editorial skills. Given the quantity of new data presented and the amount of effort involved in the basic field survey, these have to be two of the best value publications produced by the British Geological Survey.
Glen Coe in the Scottish Highlands is the site of the late Silurian to early Devonian subduction-related Glencoe caldera volcano, constructed upon Dalradian age metamorphic (meta-sedimentary) rocks. Indeed, it was the first such caldera-collapse volcano to be described, in 1909, by three of the early twentieth century's greats: Charles Clough, Herbert Maufe and Edward Bailey. They developed a cauldron subsidence model to explain the juxtaposition of thick sequences of silicic volcanic rocks with the basement rocks, involving a ‘boundary-fault’ that permitted subsidence to take place contemporaneous with the volcanism. Subsequent intrusion of silicic magmas along these ring faults yielded the granites now preserved peripheral to the caldera-fill sequences.
Kokelaar & Moore provide a master class on how to explain geological principles, whilst giving a detailed account of one of the best examples of a dissected caldera volcano. A short introductory chapter sets the scene and provides some basic definitions. We are even treated to some Scottish history and mythology. Previous studies are summarized, allowing the reader to understand the development of ideas as to how the Glen Coe volcanic rocks were erupted and the complex nature of the tectonics involved in the volcano's evolution. The authors then build up a detailed picture of the volcano's growth, whilst introducing complicated concepts in a clear and instructive manner. A huge range of lithologies is described and their formation explained: peperite, breccia, agglomerate, ignimbrite, to name but four.
The final chapter explains how the present-day dramatic scenery of Glen Coe has developed. Repeated glacial activity is described, involving destructive (erosional) processes, together with associated constructional (depositional) events.
As you read Kokelaar & Moore's account, you appreciate how instructive a field visit to Glen Coe would be and how well this book and map will guide you to all the key localities. Indeed, twenty key locations are listed on the map face. Prospective visitors are warned about the ruggedness of the terrain. Glen Coe has weather that can become ‘extremely inclement’ (to quote the authors), so be warned!
The British Geological Survey is marketing the book at £15 and the map at £12, or for a combined price of £22. I have no doubt that this is the best-valued pair of geological publications that I have ever come across. Given the work involved, they would be justified in charging twice this amount. The beautiful presentation requires that I have one set for use in the field and one set to keep on the shelf for future reference! These are not publications just for libraries, they deserve to be on the shelf and in the rucksack of anyone interested in Scottish geology.
