Stereographic Projection Techniques for Geologists and Civil Engineers (2nd Edition).

Stereographic Projection Techniques for Geologists and Civil Engineers (2nd Edition)

By Richard J. Lisle and Peter R. Leyshon Cambridge University Press, New York, 2004 ISBN 0-521-53582-4 US $35.00, softcover, 112p.

When I read this book, it brought to me pleasure and sorrow. It was a pleasure to surf through the simply explained and well-illustrated problems and it was sorrow to remember what I had to endure as a student to acquire sufficient understanding of the stereographic method, without having such a book. I remember well those years back in my native country, when I tried to study the stereographic method from a crystallographic manual, simply because there was not a good book on the geological applications of the projection techniques. Later, I discovered many structural geological manuals with introductory chapters on stereographic projection techniques, but found most of them unsatisfactory.

This lack of satisfaction is not just a personal view. My interactions with geologists of different nationalities and backgrounds indicate that only a few retain any working knowledge of the subject two or three years after graduation, even though all of them studied it; the reason for this is that they had not learned it properly in the first place. This method, no matter how simple it may look to the practicing structural geologist, requires a lot of work and concentration to be perfected and converted into an everyday tool.

Lisle and Leyshon's textbook is a carefully worded and well-illustrated introductory course in stereographic visualization of three-dimensional geological data. It is designed to satisfy the needs of the undergraduate geoscience students, but it also addresses many problems of interest for the practicing geologist. The selection of topics and the order of presentation of the practical problems are arranged in such a way that the reader is introduced painlessly into techniques of increasing complexity. The core of the book contains 46, two-page chapters illustrated with composite figures of high quality. At the end of the book, solutions are given to the exercises that are presented in some of the chapters. There are also seven appendices that have graphical templates, useful formulas and alternative projection algorithms. In light of the new trends in teaching and research, a list of freely available stereographic software is supplied at the end of the book.

The selection of problems is designed to train inexperienced geoscientists in 3-D geometry. In this aspect, the first 25 chapters are critical for the understanding of the entire content; here, all the basic operations with lines and planes are marvellously explained and the road is paved for a better understanding of more complicated problems. Rock-mechanics applications are discussed in brief in the last five chapters of the book. Crystallographic (mineralogical) applications of the stereographic projection are not discussed.

The book fills a gap in the market place. Recently, most of the authoritative manuals in structural geology offer concise introductory chapters in basic stereographic techniques; however, the explanations and the selection of problems are too economic and fail to address the needs of many students. Lisle and Leyshon's book introduces the basic stereographic concepts in a more clear and efficient way than any other textbook of similar content, except perhaps for the classical book of Phillips (1971), which is still an unbeatable short introduction, but it is now out of print. Lisle and Leyshon's book is expanded in scope and has more illustrations than the book of Phillips (1971), and is more focused and internally coherent than that of Ragan (1985). The quality of the book becomes obvious, when the reader examines the chapters dealing with rotation around an inclined axis, analysis of refolded structures or the introduction of cones and small circles. These problems are explained with less detail and efficiency in the other textbooks of Phillips (op. cit) and Ragan (op. cit).

The chapter dealing with geotechnical applications could have been more detailed; the authors include analysis of simple wedge failure, the friction cone solution and some simple analysis of daylighting conditions, but there is no mention of the mechanical basis of these methods. Comments on the resolution of stresses on discontinuity surfaces or the modified Coulomb failure criterion for fractured rocks would have facilitated the understanding of the material.

Some of the methods explained in the book have well entrenched names in the geological literature. For example, the method for finding of preferred direction by observations in arbitrary planes (pp. 38-39) is known in the geological literature as the N-plane method of Lowe (1946), which might have been mentioned in the text.

The book does not include some less common applications of the stereographic method, which can be found in the scientific journals. For example, it does not introduce operations with vectors in stereographic space. However, these applications are beyond the scope of an ordinary undergraduate course and certainly would overburden students unnecessarily.

Based on my experience in teaching structural geology, the information in the book is sufficient for a complete undergraduate course. For purely practical geological mapping projects the book offers plenty of good advice and certainly will be useful to field geologists. In conclusion, I can recommend the book to students and practitioners alike as a thorough and affordable modern introduction in the stereographic projection method.

REFERENCES

Lowe, K.E. 1946, A graphic solution for certain problems of linear structure: American Mineralogist, v. 31, p.425-434.

Phillips EC. 1971, The Use of Stereographic Projection in Structural Geology (3rd edition). New York, John Wiley, 90 p.

Ragan, D.M. 1985, Structural Geology: An Introduction to the Geometrical Techniques (3rd edition). New York: McGraw-Hill, 393 p.

Reviewed by Ivan Dimitrov

University of New Brunswick 

2 Bailey Drive

Fredericton, NB, E3B 5A3