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Book Review: Introduction to geomorphology

This book aims to introduce first-year university students to the science of geomorphology. According to the cover notes, its central theme is the functional interdependence of form, material and process. Following an overview of the aims and scope of geomorphology, two chapters consider methodological frameworks, with a strong focus on systems theory and theoretical processresponse models. Endogenic processes are swiftly dealt with in a single chapter that considers statics, plate tectonics and global landforms, without examining orogenic, epeirogenic or rifting processes in any detail. Chapter 5 considers base level, and climatic controls on exogenic systems. This is followed by an overview of rocks and minerals (and there is a later chapter dedicated to structural control), and a review of weathering processes along physical versus chemical lines. The author differentiates denudation from erosion by its areal rather than linear character, and the remainder of the book is largely organized around this distinction. Initially there is a general discussion of systems of denudation that is subdivided into sections on mass movements, wash processes, periglacial processes and the aeolian system. This is followed by a chapter on slope development. Subsequently the focus switches to fluvial erosion and associated landforms (nine chapters, 84 pages), the glacial system (one chapter, 24 pages) and the littoral system (one chapter, 30 pages). Additional chapters consider peneplains, pediments and inselbergs, karst, applied geomorphology, and there is a brief historical summary of the discipline. The book is an English translation of the author’s earlier German text (Ahnert, 1996a). There are occasional differences in preferred terminology (e.g., new channel braiding over avulsion), but the grammar is flawless, and the style is accessible for first-year students. Blackand-white line diagrams and photographs are used appropriately to illustrate the text. Most of the photographs are excellent, but there are a significant minority that fail to make their point, and will leave students wondering, among other things, exactly where the imbrication is, what a point bar is and where the stone nets are. I spotted only a few minor typographic errors. A common thread that unifies the book, and adds some personality, is the use of theoretical modelling to illustrate process-form relations, and aspects of long-term landscape development. The author acknowledges (p. 15) that ‘empirical research can investigate only a very small part of the process response system’, and highlights the complementary importance of question-generating theoretical models that are, nevertheless, based on ‘empirical experience and general physical laws’ (p. 15). This theme has it origins in the author’s own research, particularly the SLOP3D model (Ahnert, 1976: 1996b), and is welcome and unusual element in a book of this kind. However, I would have preferred a more explicit examination of the modelling that is used. Model results for particular problems are presented with descriptive but never critical commentary and, while the underlying massbalance equations are explained, there is no discussion of the degree to which they are Progress in Physical Geography 23,2 (1999) pp. 293–307