Palaeoclimatology and Palaeoceanography from Laminated Sediments

Palaeoclimatology and Palaeoceanography from Laminated Sediments
Author: Alan E. S. Kemp
Publisher: Geological Society of London
Total Pages: 278
Release: 1996
Genre: Nature
ISBN: 9781897799673

The magnitude and causes of decadal to century-scale changes in climate are major issues of global concern. The separation of anthropogenically driven change from natural 'baseline' variability within the atmosphere/ocean system is a prerequisite to identifying human impact on global climate. An understanding of past climate variability is therefore a key to predicting future climate change. The sedimentary record of the oceans, seas and lakes is produced by a series of depositional events that occur on seasonal timescales but can rarely be resolved due to mixing of the sediment by bottomdwelling organisms. Where they are preserved, laminated sediments act like tree rings to record these seasonal-scale processes, such as plankton blooms and floods, and provide a uniquely high-resolution record of environmental change. In addition, annually laminated or 'varved' sediment sequences act as geochronometers against which other timescales can be tested. Laminated sediments may therefore be used to develop records of interannual and decadal-scale variability which serve to test models of climate change. The authors cover a range of topics that include strategies for study and techniques of analysis. A series of case studies, dealing with a variety of lacustrine and marine records, illustrates the wide potential of laminated sediments as palaeoclimatic and palaeoceanographic indicators.

Encyclopedia of Quaternary Science

Encyclopedia of Quaternary Science
Author: Cary Mock
Publisher: Newnes
Total Pages: 3883
Release: 2013-03-25
Genre: Science
ISBN: 0444536426

The second revised edition of the Encyclopedia of Quaternary Science, Four Volume Set, provides both students and professionals with an up-to-date reference work on this important and highly varied area of research. There are lots of new articles, and many of the articles that appeared in the first edition have been updated to reflect advances in knowledge since 2006, when the original articles were written. The second edition will contain about 375 articles, written by leading experts around the world. This major reference work is richly illustrated with more than 3,000 illustrations, most of them in colour. Research in the Quaternary sciences has advanced greatly in the last 10 years, especially since topics like global climate change, geologic hazards and soil erosion were put high on the political agenda. This second edition builds upon its award-winning predecessor to provide the reader assured quality along with essential updated coverage Contains 357 broad-ranging articles (4310 pages) written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. Facilitates teaching and learning The first edition was regarded by many as the most significant single overview of Quaternary science ever, yet Editor-in-Chief, Scott Elias, has managed to surpass that in this second edition by securing even more expert reviews whilst retaining his renowned editorial consistency that enables readers to navigates seamlessly from one unfamiliar topic to the next

Use of Proxies in Paleoceanography

Use of Proxies in Paleoceanography
Author: Gerhard Fischer
Publisher: Springer Science & Business Media
Total Pages: 768
Release: 2012-12-06
Genre: Science
ISBN: 3642586465

Paleoceanographic proxies provide infonnation for reconstructions of the past, including climate changes, global and regional oceanography, and the cycles of biochemical components in the ocean. These prox ies are measurable descriptors for desired but unobservable environmental variables such as tempera ture, salinity, primary productivity, nutrient content, or surface-water carbon dioxide concentrations. The proxies are employed in a manner analogous to oceanographic methods. The water masses are first characterized according to their specific physical and chemical properties, and then related to particular assemblages of certain organisms or to particular element or isotope distributions. We have a long-standing series of proven proxies available. Marine microfossil assemblages, for instance, are employed to reconstruct surface-water temperatures. The calcareous shells of planktonic and benthic microorgan isms contain a wealth of paleoceanographic information in their isotopic and elemental compositions. Stable oxygen isotope measurements are used to detennine ice volume, and MglCa ratios are related to water temperatures, to cite a few examples. Organic material may also provide valuable infonnation, e. g. , about past productivity conditions. Studying the stable carbon isotope composition of bulk organic matter or individual marine organic components may provide a measure of past surface-water CO 2 conditions within the bounds of certain assumptions. Within the scope of paleoceanographic investigations, the existing proxies are continuously evolving and improving, while new proxies are being studied and developed. The methodology is improved by analysis of samples from the water column and surface sediments, and through laboratory experiments.