John A. Matthews

Studies on a gelifluction lobe, Jotunheimen, Norway: 14C chronology, stratigraphy, sedimentology and palaeoenvironment

A turf-banked gelifluction lobe in south-central Norway is described together with detailed 14C dating of buried soil material, measurements of current activity, and sedimento-logical, geotechnical and micromorphological analyses. Three stratigraphic units are recognised; a silty sand upper unit (Unit 1) overlying heterogeneous sandy sediments containing organic bands up to 2 cm thick (Unit 2), which in turn overlies a buried soil of thickness 75 cm (Unit 3, the Main Buried Soil) developed on the underlying till. Analyses indicate that the gelifluction and frost creep responsible for the formation of this lobe affected not only till but also colluvial (slope wash) deposits. Particularly in Unit 2, well-sorted layers of fine sand and coarse silt alternating with organic bands, indicate episodic accumulation of colhivium separated by intervals of pedogenesis.Nineteen 14C dates were obtained from eight points along the length of the Main Buried Soil and from a vertical section through the lobe, inclu...

Limitations of 14C Dates from Buried Soils in Reconstructing Glacier Variations and Holocene Climate

The accuracy with which the date of burial of a palaeosol can be estimated is assessed using a very detailed radiocarbon-dating study of one buried soil horizon. Twenty six depth controlled dates have been obtained from physico-chemically fractionated samples of the organic surface (FH) horizon of a humo-ferric podzol buried by the southern Norwegian glacier Haugabreen at its ‘Little Ice Age’ maximum limit. The 14C dates show an order of magnitude increase in age with depth from 485 ± 60 to 4020 ± 70 14C years B.P. over 14.5cm. Although this age range suggests potential errors of the order of thousands of years, the age/depth gradient appears to provide a basis for quite accurate estimates of the date of soil burial and of the date of moraine formation.

Global Changes of the Past. Papers Arising from the 1989 OIES Global Change Institute

mental change particularly over the last 15 000 years. Chapter 2 deals with the late and postglacial periods, and chapter 3 with prehistoric communities as agents of environmental change. This traces the origin and spread of hominids where the impact on environment can be based on the interpretation of pollen diagrams with few references to other forms of environmental change. Chapter 4 begins with environmental change in the Mediterranean area during the Greek and Roman empires but then concentrates on the UK from the dark ages and Medieval periods to Tudor and post-Tudor influences on the British landscape. This provides a synopsis of historical geography prior to considering environmental change in industrial Britain. A useful section on the environment as a political issue emphasizes Britain but does not refer to NEPA in detail. Environmental change in Africa and the new world since 1500 and in Australia concludes the chapter. The next four chapters deal with change in the last two centuries approached by considering environmental change due to post-1700 industrialization, embracing (in chapters) mineral extraction, changes in environmental quality, reclamation of mine damaged land, change due to fossil fuel burning and industrial chemicals, acidification, ozone and lead problems, and the disposal of waste materials. The environmental impact of agriculture in the developed world (Chapter 6) ranges from habitats and hedgerows to soil erosion, fertilizers and salinization effects and even includes a section on the impact on water supplies prior to a good section on chemical influences associated with crop production. This chapter is parallelled by one (7) on the ,environmental impact of agriculture in the developing world which is subdivided accorded to region, by concentrating on arid and semi-arid areas, rain forest regions and then on mountain areas. The final chapter in this group deals with other aspects of landscape change represented by forestry, recreation, tourism and sport, and biotechnology including genetic engineering. This book certainly covers a great range of material and uses a number ,of imaginative and very positive ways of presenting the text. Each chapter has a summary in bold type at the beginning and some similar summaries occur at the beginning of sections followed by more detailed sections which emphasize specific examples. The text is largely written in non-technical language which assumes some knowledge of processes but is largely devoid of technical or quantitative approaches so that GCMs for example are mentioned on p.160 but do not appear substantially until nine pages from the end of the book and then in a non-technical form. There is an extremely substantial bibliography, although the avowed intention of the book, to emphasize literature published post 1984, is not explained and there is no reference to Onvell amongst well over 1000 references. It is also pleasing to see a volume which although reflecting the perspective and research interests of the author, does largely succeed in getting free from traditional disciplinary boundaries. Inevitably a volume covering the enormous subject of global environmental change means that any one reader will find aspects of emphasis and presentation where they would differ from the author. Thus despite the extensive references certain names such as Zeuner, Vita Finzi, Sauer and Starkel do not appear and there is surprisingly no reference to subjects such as geoarchaeology or to palaeohydrology. Emphasis is very much on land-use change and general environmental change with no space to consider details of how changes occur and what is actually involved. There is a tendency to rely in certain parts of the text on particular references such as Iversen (1958) on page 38, Toy and Hadley, and Blunden for sections of Chapter 5 and elsewhere certain favourite secondary sources are obviously preferred. In addition, there is a distinct difference between the level of detail and explanation in the bold type introductions at the beginning of a chapter or section, and the succeeding text with detailed examples. To inform, enthuse and spark the imagination of the student reader it would perhaps have been helpful to have a clearer structure in the detailed text of each chapter, with more diagrams specifically conceived to explain the structure of the chapter and to convey particular messages. hlany of the diagrams are simply repeats of specific ones in the existing literature and as a consequence there is a fascinating range of world outlines: the shape of the word varies very dramatically when one compares pages 158, 232 and 237 for ex amp I e . Overall this volume covers a large amount of material and juxtaposes some interesting subject areas. It is really about the history of major aspects of global environmental change illustrated by examples. The student reader will appreciate these examples but may perhaps wish for more attention devoted to a level of explanation intermediate between the basic summaries and the detailed statements which are very largely example-based and if the volume was revised the student would certainly be helped by more diagrams. However, this book provides a very useful compilation of material related to a significant subject of increasing interest and could be used in support of a growing number of higher education courses. In the conclusion .and prospect the author does distinguish between a pessimistic scenario and an optimistic one which relies upon the ‘technology will fix it’ or ‘invent a solution’ expedients, but it is not clear how a resolution will be achieved especially as positive feedback is suggested to be particularly significant. The fact that resolution will depend upon a political solution is hinted at in the final pages where three major areas that are deemed to merit further investigation and research investment are also identified. These areas of palaeoenvironmental studies in determining the causes, rates and impact of climatic change; the inadequacy of predictive models; and the roles of science and technology; perhaps need to be supplemented by others which relate particularly to the social and economic decision making that will be imperative to implement the results of increased appreciation of the consequences of global environmental change.

Book Review: Arctic natural archives

explains the concept of degrees of freedom) and many worked examples. Further, the examples are coded by illustrations (drawn by Jo Wright), which are used to aid navigation around the book. As a result of the above, combined with clear use of English, I found the book easy to read. Further, it contains many useful tips for undergraduates that should help to avoid the common pitfalls found in, for example, undergraduate dissertations and research projects. There are five useful appendices. The inclusion of Appendix A, ‘Basic mathematical methods and notation’ (which includes addition, subtraction, multiplication, division . . .), if nothing else, gives you a feel for the intended audience. In terms of layout and appearance, the book is produced neatly by Routledge. I could count the typographical errors that I found on one hand. The book may be impressive in its structure and its structural cues, but its content is relatively standard. The first two chapters (1, ‘Project design; 2, ‘Describing data’) are typical of many introductory statistics books covering topics such as measures of central tendency and the central limit theorem. However, I found the inclusion of Box 1.1 on ‘Safety and legal issues’ novel (perhaps a sign of our increasingly litigious times?) and Table 2.8 on SI units useful. Further, Box 1.2, which describes accuracy and precision, is also useful (how many times are these terms misused?), but it does not go far enough. Accuracy and precision are described with scant mention of bias, which is potentially misleading given that accuracy = unbiasedness + precision. Chapter 1, like many statistics textbooks, describes the process of ‘data collection’. Personally, I find this phrase annoying. We rarely ‘collect’ data. An example would be gathering numbers from the air using a butterfly net! More often than not, we measure. The third chapter (3, ‘Using statistics to answer questions’) gives away the emphasis of the book and primes the reader for the chapters that follow. This emphasis is on the traditional goal of statistical hypothesis testing. Many statisticians are turning away from this kind of approach, in part, because of its inherent arbitrariness. Further, in my opinion, modelling, prediction and design are potentially more interesting. The remaining chapters (4, ‘Differences between two samples’; 5, ‘Relationships between variables’; 6, ‘Analysing frequency data’; and 7, ‘Differences between more than two samples’) complete the book. These chapters deal with a predictable set of approaches (for example, t test, Mann–Whitney U test, F test) for testing for significant differences and significant relations between variables. Clearly, there is more to statistics than hypothesis testing. However, given that the audience is likely to comprise first-year students, primarily interested in some discipline other than statistics, this book does an excellent job of conveying both (i) the procedure for applying these tests and (ii) the meaning underlying them. Overall, this is an excellent book, written on a standard topic, that undergraduates should find useful (i) as a guide to their first-year statistics option and (ii) as a reference when writing their dissertation or research project report.

Book reviews: Frenzel, B., editor, Pons, A. and Gläser, B., co-editors, 1991: Evaluation of climate proxy data in relation to the European Holocene. Stuttgart: Gustav Fischer Verlag. xii + 309 pp. 96 DM paper. ISBN: 3 437 30688 X

if anthropogenic factors should prove to have been a minor factor in the evolution of Holocene climates, many proxy indicators of climate were drastically affected by human impacts, and there is a major need to separate these effects from those of the ’natural’ background so that present and future anthropogenic climatic changes are correctly identified. There can, of course, be no better region than Europe to study this question because of the long history of human impact combined with the long history of scientific investigations already directed towards the palaeoclimate of the continent. However, most of this scientific effort has been carried out by individuals or small groups. The EPC programme’s main objective is to summarize the existing information in a comparable and readily accessible way, where possible in terms of quantitative, Europe-wide palaeoclimatic data. The approach adopted has been to give high priority to the preparation of palaeoclimatic maps for particular time-slices (’timewindows’) of the Holocene. Thus, it will be possible to compare and contrast climates at 9500, 8500, 7500, 6500, 4500, 3500, 1800, 1400, 600 and 140 BP, based on the varied

Holocene book reviews: Long-term ecological research: an international perspective Edited by Paul G. Risser. Chichester and New York: John Wiley & Sons, 1991, 294 pp., £69 hardback. ISBN 0-471-93005-9

Harkness and Walker describe the benefits provided by careful selection of the organic components used for age determinations for setting the chronology of a late glacial carbon isotopic record. But they note that even in ideal situations, the resulting chronology still lacks the ’depth of focus’ necessary to answer some specific chronological questions. Preece examines a suite of dates from a colluvial sequence, and describes the sources of variability in those dates that arise from spatial variations at the locality, differences between charcoal and shell dates, variations among organic components, differences between conventional and AMS dates, and finally, among replicate samples. Perhaps surprisingly, the results convey the overall impression of relative consistency among the age determinations. A bit more of a cautionary tale is told by Bjbrk, Hjort, Ing6lfosson and Skog, who describe a large set of dates on material from the Antarctic Peninsula. When age determinations from a heterogeneous mixture of materials and environments are combined, the sources of uncertainty in the dates become apparent, and forethought must inform the interpretation of the assemblage. The sources of uncertainty unique to Antarctic environments are also clearly described.

Conclusion: Choice and Limitations of Statistical Techniques

“For the most part, Statistics is a method of investigation that is used when other methods are of no avail; it is often a last resort and a forlorn hope. A statistical analysis, properly conducted, is a delicate dissection of uncertainties, a surgery of suppositions.” M. J. Moroney (1956), p.3.

2 – Measures of Central Tendency

The purpose of this section is to enable you to describe a set of numeric data using a single value. The value you calculate will describe the centre of the set of data. There are various ways to describe this notion of centre. For example, a car dealer might claim that the average selling price of a two-year-old used car is

The status of the ‘Little Ice Age’ in southern Norway: relative-age dating of Neoglacial moraines with Schmidt hammer and lichenometry

14 500. What does this average tell you? Does this average take into account the number of each type of car sold? What if the dealer doesn’t sell very many used cars, but occasionally sells a very expensive car? The influence an outlier such as this can have must be taken into consideration. It is important to know what kind of average is being used. You are already familiar with the mean, the median, and the mode. The examples that follow outline situations in which each measure of central tendency is most useful.