The authors are well known in the world of clay mineral science. Until recent times, they have been associated with a physico-chemical approach to the development of clay minerals. In The Origin of Clay Minerals in Soils and Weathered Rocks they demonstrate their late conversion to accepting that biological activity and organic chemistry may play an important role. This book is part textbook, part personal hypothesis, part message, written in the hope that ‘some young people with stars in their eyes will heed this call, and we can proceed into the 21st century on a better footing than when we left the 20th’. There are a contents list, eight chapters, six annexes (i.e. appendices), a reference list, a general index and 195 figures (black/white) and 23 tables.
Chapters 1 and 2 deal with the physico-chemical properties and structure of clay minerals and the geochemical systems involved in the development of secondary clay minerals in weathered rocks and soils. Chapter 3 covers general controls on the formation of weathering profiles and soils, and Chapter 4 the details of rock–water interaction involved in the weathering of igneous, metamorphic and sedimentary rocks. Chapter 5 discusses the effects that vegetation and agricultural practice have on clay mineral assemblages. Chapter 6 covers the influence of climate and time on clay minerals in weathering profiles and soils, while Chapter 7 discusses physical movement of soil material within soil profiles and the development of topographically controlled catenas. The final chapter summarizes the authors’ ideas on the future of clay mineral science in the use of soils in modern and future societies. Appendices provide additional information on clay mineral polytypes, mixed-layer clay minerals, cation exchange capacity, hydroxide inter-layer minerals, phase diagrams, and kinetics. The authors’ approach is that soil development consists of three phases. Initially an abiological alteration of the parent rock is controlled by water–rock interaction. This may result in very varied but localized clay mineral alteration products. This is maintained until the physical structure of the rock collapses (saprock to saprolite) when consistent conditions become widespread and a more simplified clay mineral assemblage develops. The subsequent establishment of vegetation marks the third phase in which organic matter and biological activity play an important role in modifying the clay mineral assemblages. There is extended discussion of the productive soils of temperate climates and the effects of agricultural practice. There is reference to the authors’ controversial views on the potassium and silica cycles and the development of soil mixed-layer clays and illite. However interesting, these ideas would gain more scientific credence if the authors had considered how they should be tested (radiometric dating, tracer studies, detailed chemical, structural and morphological analysis).
This book is expensive, unnecessarily long and insufficient attention has been given to user friendliness (e.g. general index where roughly 60% of entries have too many unqualified page references, variable quality of figures, etc.); it is not suitable as a student textbook nor for the cash-strapped library. In spite of limitations it could bring the reader up to date on popular thinking on green, ecologically friendly aspects of clay minerals within agricultural practice.