Geomorphology

Rating: ★★★★☆

Robert S Anderson and Suzanne P Anderson. 2010. Geomorphology: The Mechanics and Chemistry of Landscapes. Cambridge University Press. ISBN 978 0 521 51978 6

The title says much about the geomorphological perspective – (long) gone are the days of descriptive landscapes, although these have always had a use. Current work is focussed far more on the science of the processes. This is crucial because not only does it reflect more accurately the academic world in which this science now lives (most university geography departments are now  fragmented by speciality) it better helps tie the physical environment with the biological one. At a time when topics like global warming, biodiversity and atmospheric changes are realising the importance of the physical Earth, there is a need to bring this to students’ attention.

We start with an overview of the subject but unlike many, it starts with some fundamental principles, the first of which is conservation. Although this might seem more at home in a wildlife text the idea is to get the student to consider the rates at which products are produced, destroyed and moved (what would have been seen as production, weathering, erosion and transport in earlier texts!).  There follows a consideration of global forces (mostly energy based) and the timescales of events. A very brief chapter covers global hypsometry (distribution of heights) which is followed by a far more substantial look not just at plate tectonics but the mechanics and rates of change of flow. There is a return to tectonics in the next chapter but this is very much the study of crustal deformation by folds and faults, the impact of earthquakes and the mechanics of seismology. If this is seen as the opening set of chapters then the resulting perspective for the reader is one of the science of motion, rates of change and the resulting landforms.

From this point, the text moves to a more basic treatment of the subject by taking well-known elements and examining how they work and the impacts they have. Typical is the first of these chapters which looks at atmospherics. The radiation patterns and the resultant atmospheric processes are used to explain not just circulation but also the distribution of components and the impact of the atmosphere on the landscape. Given the importance of dating especially when considering rates of change, the next chapter is a comprehensive overview of the range of methods available (and where they might be used). This work has grown considerably in the last 20 years and its instructive for the older reader to see by just how much compared to older books. Weathering comes next and although we still have the basic sub-divisions of physical, chemical and biological, the trend is to examine the actual processes by which they work (often similar if we consider tree root and ice heave!). Glaciers and periglacial landforms are the next topics. The focus is on flow rates, principles  and the mathematics of flow rather than the resulting landforms but this has the advantage of taking us away from the feature and looking at the system behind it. Likewise, hillslopes are a study of flow processes but also descriptions of a number of experiments to study this. Rivers have always been a staple of geomorphology tests and the three chapters devoted to various aspects of this – water, river and channels – shows it still to be the case. This is followed by sediment dynamics and aeolian processes, both depositional and erosional. Two chapters on more focussed processes, coasts and floods, bring us towards the end. However, before the appendices of mathematics, we get to see something of how it goes together. An opening quote attributed to Tesla has some merit: ” Today’s scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality”. The remainder of the chapter shows how some of these equations can be put together.

Tesla is perhaps the ideal quote for this book. It’s both revealing and concealing. It reveals the physical principles which underpin geomorphological  processes but conceals many of the terms we need to describe the landscape. We see the mechanisms but can’t name features! This is not to criticise the book but to place it in the canon of works. It is not a book for the complete novice nor is it one for the mathematically timid! It does what it says – it highlights the mechanics and mathematics of those physical processes we wish to examine. It’s important because the rates and magnitudes of change are fundamental to our understanding of how the Earth works. It’s how we need to think at a time when human impact reaches similar orders of magnitude to natural processes. However, it’s also essential to appreciate the landscape and to be able to describe it. as such this is an excellent companion to those texts and an essential part of the modern students work.

 

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