Frontiers in Geochemistry is a collection of essay-reviews from well known authors and arising from a meeting of the International Association of Geochemistry in Oslo, 2008. The first part of the book comprises seven chapters which review the insights that geochemistry provides on our current state of knowledge of both the deep Earth and surface processes, whereas the second part is forward looking to the frontiers of geochemistry and the likely future developments in this field.
The introductory chapter by Kamber provides an overview of the geochemical and secular evolution of the Earth's mantle and the lower continental crust. The main focus of this review is to show the usefulness of lead isotopes in understanding mantle and crustal evolution. A chapter from Hawkesworth and colleagues provides a review of their recent work on zircon geochemistry and how it is able to unravel the complexities of the evolution of the continental crust. Haase completes this trilogy of deep Earth contributions, providing a balanced review of the geochemistry of mid-ocean ridge basalts and an interpretation for what this means for our modern understanding of the origin of the oceanic crust. Sadly, this chapter only discusses mid-ocean ridge basalts; oceanic plateau and ocean island basalts are not covered.
In a series of contributions on the geochemistry of Earth surface environments, Holland provides a review of the history of our understanding of atmospheric oxygen. The latter part of this chapter caught my attention. Here, Holland deals with modern geochemical evidence for the change in the levels of atmospheric oxygen over geological time. In a forward-looking final section he proposes a model in which the change in levels of atmospheric oxygen is related to the increased amount of recycling of carbon, sulphur and water into the mantle over geological time. Gislason and Oelkers demonstrate the complex nature of weathering as a function of temperature, runoff, biogenetic activity, the chemical and mineralogical composition of the parent rock, and tectonic activity. This is followed by a review by Paces on the ‘Geochemistry of secular evolution of groundwater’. Again, complexity of process is the theme. This section concludes with a review of stable isotope geochemistry by Hoefs, focussing on four important areas—characterizing water chemistry, study of hydrothermal ore deposits, carbonate thermometry applied to palaeoclimatology and recognition of biosignatures in the geological record.
The second part of the book claims to take us to the frontiers in geochemistry, demonstrating new fields where its application is proving fruitful. The first of these is an account of the process of carbon dioxide sequestration and storage by Kharaka and Cole. Much of the focus of this chapter is on CO2 sequestration in sedimentary basins and the authors present two detailed case studies. A key issue which needs to be resolved concerns leakage from the injection site. The chapter on microbial geochemistry by Bennett and Omelon describes the interactions between microbes and mineral surfaces. These authors argue that such interactions are neither inert nor accidental. The chapter on nanogeochemistry by Wang and co-workers reviews the advances in the field of nanomaterials as applied to geochemistry. The authors describe the chemistry of nanophases and of nanopores; in short, very small particles behave differently from larger particles. Clear geochemical and mineralogical applications are currently few, or at least ill defined.
The final two chapters deal with human aspects of geochemistry. I remain unconvinced of the merits of urban geochemistry (Jartun and Ottesen) as a new sub-discipline of geochemistry. The final chapter by Schwartcz describes the application of geochemistry to the fields of archaeology and anthropology, but this area is better characterized as a ‘mature field expected to grow in importance’ rather than a frontier in geochemistry.
My main concern as I read this book was its target audience; it is not clear who they might be. Neither is the purpose of the book clear. If it is a position statement on the health of modern pure and applied geochemistry then it is a worthy contribution. But of the 12 chapters, only two represent genuine ‘new frontiers’. If, on the other hand, this is intended as a geochemistry text, then it fails. The contributions are very variable. About half the chapters represent in-depth reviews of broad areas of geochemistry and as such are highly suitable for final-year undergraduates and professionals wanting an update on our current state of knowledge. Some chapters, however, are much more personal, historical views of a sub-discipline, whilst others are speculative, forward-looking articles about future applications of geochemistry, but with no deep sense of methodology and rigour. A useful reference text, nonetheless—buy it for your library.