Absolute Age Determination

The spectrum of physical and chemical dating methods now covers the entire range of Earth history. But there are so many methods that it is becoming increasingly difficult to select those that are appropriate for solving a specific problem. The objective of this book is to cover the whole spectrum of methods and to give examples of their applications. Thus it is addressed to everybody interested in the application of physical and chemical dating methods to the geosciences and archeology. It is especially valuable as a concise, but comprehensive reference for students and practitioners.

With the growing recognition during the last two centuries that the Earth has an immense age and processes over long periods of time have changed the morphology and composition of the Earth's crust, geologists have become increasingly interested in determination of absolute ages. A rela tive geochronology was established on the basis of the lithostratigraphic and biostratigraphic principles developed during the last century. With the discovery of radioactivity, the basis for a new geoscientific discipline - geochronology - was established (Rutherford 1906). It is the study of geological time, based mainly on the time signatures provided by the isotopic composition in geologic materials. The isotopic signature in a rock yields more information than that provided by the geochemical signature alone because it reflects the origin and history of the element in the rock. The aim of geochronology is to calibrate and standardize chronostrati graphic scales, to develop geological time scales that have a sensitive or at least useful resolution in order to place the geological events in the correct chronological order, and to assign their proper time spans. In practice, the application of geochronology is much wider because the data in the "natural archives" often provide information on the origin, genesis, and history of the materials. This, of course, requires an understanding of the geochemical behavior of the substances involved.

Dating the Quaternary, which covers approximately the last 2 million years, has experienced considerable progress over the past few decades. On the one hand, this resulted from the necessity to obtain a valid age concept for this period which had seen tremendous environmental changes and the advent of the genus Homo. On the other hand, instrumental improvements, such as the introduction of highly sensitive analytical techniques, gave rise to physical and chemical innovations in the field of dating. This rapid methodological development is still in full progress. The broad spectrum of chronometric methods applicable to young rocks and artifacts also becomes increasingly intricate to the specialist. Hence, it is my goal to present a comprehensive, state-of-the-art sum mary of these methods. This book is essentially designed as an aid for scientists who feel a demand for dating tasks falling into this period, i. e., Quaternary geologists and archaeologists in the broadest sense. Since it has been developed from a course of lectures for students of geological and archaeological sciences, held at the University of Heidelberg, it certainly shall serve as an introduction for students of these disciplines.

This text focuses on the principles and methods of using growth layers formed in teeth and bones of mammals to make a judgement on essential traits of the animal's life history. In nearly all mammalian species, including man, the age of individuals can be determined from the number of growth layers and, at least in some of them, it is possible to estimate the season of an animal's birth and death, age of sexual maturation, periodicity of reproduction, certain feeding habits and other aspects of the individual's biology. It is also possible, from tooth-enamel analysis, to assess doses of radiation accumulated by animals and human beings during their lifetime.;This book is intended for zoologists, wild-game biologists and zoo archaeologists, but some of the sections could also be of interest for anthropologists, radioecologists and conservation biologists.

Lakes and reservoirs hold about 90% of the world's surface fresh water, but overuse, water withdrawal and pollution of these bodies puts some one billion people at risk. The Encyclopedia of Lakes and Reservoirs reviews the physical, chemical and ecological characteristics of lakes and reservoirs, and describes their uses and environmental state trends in different parts of the world. Superbly illustrated throughout, it includes some 200 entries in a range of topics, including acidification, artificialisation, canals, climate change effects, dams, dew ponds, drainage, eutrofication, evaporation, fisheries, hydro-electric power, nutrients, organic pollution, paleolimnology, reservoir capacities and depths, sedimentation, water resources and more.