Nora Noffke has produced an excellent text book covering a relatively recently developed field – the study of microbial mats in shallow water environments. Stimulated by the geobiological approach advocated by the Oldenburg/Wilhelmshaven group of Wolfgang Krumbein and Gisela Gerdes, Nora Noffke has taken the field to new depths through her in-depth investigations. She provides an excellent introduction that sets the scene for the concepts of geobiology and, more specifically, microbially-induced sedimentary structures (MISS). This is followed by an exhaustive analysis of the different types of MISS, their preservation in the geological record and their usefulness in palaeoenvironmental interpretations.
MISS apparently form in a particular ecological window – fine sandy sediments deposited in a shallow water environment subjected to a moderate hydraulic regime. Noffke provides a good analysis of the stages of formation of these photosynthetic microbial mats and their environmental influence. Her description of the processes leading to the preservation of MISS in the geological record is thorough, although she could have cited more recent literature with respect to the fossilisation of microorganisms. The section on how to search for and identify MISS in rocks will greatly help students of MISS.
Noffke concentrates on one particular example in the fossil record, the 2.9 billion-year-old MISS in the Pongola Group of South Africa, that she illustrates with useful photographs of similar modern structures. She claims that the MISS in the Pongola sediments were formed by cyanobacterial mats, similar to recent and modern MISS, thus making them the first known examples of cyanobacteria. The evidence for this is, however, tenuous and the purported images of fossil cyanobacteria are not convincing. But could MISS have been formed by anoxygenic photosynthesising microbial mats? Nevertheless, the very detailed descriptions she provides of MISS in the Pongola sands are very clear and didactic.
The book is well laid out and the text is clear and well-written, although the font is rather small. Noffke has a fluid style that is a pleasure to read. The various aspects of MISS, both modern and ancient are well illustrated. There is slight repetition between the extensive introduction and the exhaustive descriptions but I recommend it to both the general reader, as a good introduction to MISS, and to the dedicated student of MISS in the geological record.
