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Holocene book review: Past Glacial Environments

Both rewards and pitfalls await the editors of multi-authored textbooks. On one hand, a large cast of authors can bring expert knowledge of a wide range of topics, promising breadth and depth of coverage far beyond what can be achieved by any one individual. On the other hand, editors must contend with varying interpretations of their brief, and may struggle to reconcile diverse styles, approaches and levels of engagement from an unruly crowd of contributors with scant regard for deadlines or the rules of grammar. It is little surprise therefore that Past Glacial Environments has both strengths and weaknesses. It boasts rich and varied content, including several excellent and up-to-date chapters; but there are also gaps and uneven coverage of topics, and at times one wishes, the editors had imposed a clearer overall sense of direction and purpose. The first odd thing about this book is its title. This is actually the second, extensively revised edition of Modern and Past Glacial Environments, John Menzies’ single-volume distillation of his double-barrelled opus Modern Glacial Environments and Past Glacial Environments. The decision to drop ‘modern’ from the title of the new edition seems strange, as the book has as much to say about modern glacial environments as it does about the past and contains chapters that can trace their ancestry back to each of the two original volumes. If the aim was to streamline the title, what was wrong with Glacial Environments? The book is arranged in five parts: I. The Prequaternary; II. The Quaternary; III. Glacial Processes; IV. Techniques & Methods; and V. Problems and Perspectives. Parts I and II contain only three chapters between them; if they had been combined in a single section named ‘Earth’s Glacial History’, the editors could have avoided using the dreadful term ‘Prequaternary’, which is equivalent to standing on a vegetated moraine looking at geological time through the wrong end of a telescope. Nevertheless, the three chapters all add value to the book, although their widely differing emphases and perspectives make for a lack of overall coherence. Grant Young’s chapter provides a brief overview of Precambrian glaciations, including the extreme ‘Snowball Earth’ panglaciations of the Cryogenian, and touches on some of the big questions regarding their causes. The following chapter on early Palaeozoic (mainly Ordovician) glaciations by Le Heron, Tofaif and Melvin has a narrower temporal and geographical focus and is hence richer in detail. It is well illustrated with numerous examples of beautifully preserved erosional and depositional forms, as well as reconstructions of regional palaeogeography. Finally, Ehlers, Gibbard and Hughes’ authoritative and concise chapter on the Quaternary focuses very much on the overall chronology, leaving questions of forcings and feedbacks to a chapter by Sandra Passchier much later in the book. The great Permo-Carboniferous glaciation gets passing mention in the Precambrian chapter, but then is never heard of again. Major gaps such as this, and the widely differing approaches taken by the authors mean that, despite their individual merits, the chapters in Parts I and II do not add up to a comprehensive and rounded whole or provide the firm foundation that the editors had perhaps imagined. Parts III and IV provide the main substance of the book, with a succession of chapters focusing on different glacial processes, environments and methods. Some of the chapters are updated from previous editions, such as Derbyshire and Owen’s classic ‘Glacioaeolian Processes, Sediments, and Landforms’, whereas others are brand new or extensively revised. Most of the bases are covered at a good level for geography or geology undergraduates, with mostly up-to-date and well-chosen reference lists. There are good, useful and well-illustrated chapters on subglacial processes and sediments (Menzies, van der Meer and Shilts), glaciotectonics (Emrys Phillips), the marine geological record (Sandra Passchier) and glaciohydrogeology (Ravier and Buoncristiani). Particular stand-outs are the chapters on glaciovolcanism (John Smellie) and modern glaciomarine environments and sediments (Domack and Powell). The former is lively, readable and informative, illustrating general principles with a series of well-chosen case studies. Domack and Powell’s chapter is an excellent mini textbook in its own right, full of ideas and rich in detail, and a magnificent tour de force by a pair of outstanding scientists who have led the field for as long as I can remember. Gene Domack passed away in November last year, and this chapter is a monument to his considerable abilities and achievements. A good range of techniques is covered in Part IV, including soils and palaeosols (Mason and Jacobs), till mineralogy and geochemistry (McClenaghan and Paulen) and geochronology (Timothy Jull). The latter is especially good, providing a detailed and admirably clear primer for students. Kaleb Wagner provides a nice overview of the geographic information system (GIS) techniques that have revolutionised landform mapping and palaeoglaciological reconstructions, although this chapter, along with that on lithofacies and stratigraphy (Jonathan Lee), is inexplicably placed in Part III rather than Part IV. The choice of some techniques for inclusion clearly reflects the interests and research foci of the editors, so the coverage feels unbalanced in places. Menzies and van der Meer allot themselves over 50 pages to discuss the dark arts of micromorphology and microstructure, whereas standard and essential techniques such as fabric analysis, clast morphology and particle-size analysis get not a whisper. One of the most surprising–and best–chapters in the book is that on ice sheet and glacier modelling by Richard Hindmarsh. This highly detailed, technical and masterful review of glaciological modelling is quite unlike anything else in the book and really serves a different readership. Alongside pages of equations governing glacier dynamics, Hindmarsh writes readable discussions of topics such as instability theory of drumlin formation. Theories of drumlin formation are also discussed much earlier in the book Holocene book review 780161 HOL0010.1177/0959683618780161The HoloceneHolocene book review book-review2018