Geology And Seismic Stratigraphy Of The Antarctic Margin

Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 71. The Antarctic Ice Sheet has greatly affected global climate, sea level, ocean circulation, and southern hemisphere biota during Cenozoic times. Much of our understanding of the evolution of the ice sheet has been inferred from isotopic studies on distant deep-ocean sediments, because few Cenozoic rocks are exposed on the Antarctic continent. Yet, large differences occur between past ice volumes inferred from isotopic studies and those inferred from low-latitude sea-level variation. The massive quantities of glacially transported terrigenous sediments that lie beneath the Antarctic continental margin provide an additional, more direct record of the inferred ice sheet fluctuations. Volume 68 addresses the history of ice sheet fluctuations as recorded by geological and geophysical investigations of selected areas of the Antarctic continental margin. As described below, the volume gives data and results from on-going research by a major multinational project directed toward better understanding the impact of Antarctic Ice Sheet fluctuations on global sea levels and climates.

Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 71. The Antarctic Ice Sheet has greatly affected global climate, sea level, ocean circulation, and southern hemisphere biota during Cenozoic times. Much of our understanding of the evolution of the ice sheet has been inferred from isotopic studies on distant deep-ocean sediments, because few Cenozoic rocks are exposed on the Antarctic continent. Yet, large differences occur between past ice volumes inferred from isotopic studies and those inferred from low-latitude sea-level variation. The massive quantities of glacially transported terrigenous sediments that lie beneath the Antarctic continental margin provide an additional, more direct record of the inferred ice sheet fluctuations. Volume 68 addresses the history of ice sheet fluctuations as recorded by geological and geophysical investigations of selected areas of the Antarctic continental margin. As described below, the volume gives data and results from on-going research by a major multinational project directed toward better understanding the impact of Antarctic Ice Sheet fluctuations on global sea levels and climates.

Understanding the sedimentary and geophysical archive of glaciated margins is a complex task that requires integration and analysis of disparate sedimentological and geophysical data. Their analysis is vital for understanding the dynamics of past ice sheets and how they interact with their neighbouring marine basins, on timescales that cannot be captured by observations of the cryosphere today. As resources, sediments deposited on the inner margins of glaciated shelves also exhibit resource potential where more sand-dominated systems occur, acting as reservoirs for both hydrocarbons and water. This book surveys the full gamut of glaciated margins, from deep time (Neoproterozoic, Ordovician and Carboniferous–Permian) to modern high-latitude margins in Canada and Antarctica. This collection of papers is the first attempt to deliberately do this, allowing not only the similarities and differences between modern and ancient glaciated margins to be explored, but also the wide spectrum of their mechanisms of investigation to be probed. Together, these papers offer a high-resolution, spatially and temporally diverse blueprint of the depositional processes, ice sheet dynamics, and basin architectures of the world’s former glaciated margins; a vital resource in advancing understanding of our present and future marine-terminating ice sheet margins.

Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 53. The Cold Deserts of Antarctica and the Polar Deserts of the High Arctic, the latter of which includes the Queen Elizabeth Islands, northern Greenland, Svalbard, Franz Josef Land, Severnaya Zemlya, and a few other localities, have cryogenic soils with desertlike features. Both sectors have soils with a mineral appearance, desert pavement, small to nonexistent organic components, and low ground temperatures. Both are underlain by permafrost and are subject to cryogenic processes. Whereas virtually all of the soils in Antarctica are well drained, in the High Arctic the soil pattern consists of a mosaic of Polar Desert soils, as well as various hydric varieties including shallow bogs. In the Polar Deserts the landforms, especially the surficial deposits, are much younger chronologically than their Cold Desert counterparts. Polar Desert soils generally have a more acid reaction than Cold Desert soils. Moisture regimes are quite different in the two sectors. Cold Desert soils have a dry condition even down to the frost table. Polar Desert soils are moist during early summer thaw, however, and are subjected to occasional summer rainfall and probably receive some moisture from condensation; the zone above the receding frost table is usually quite wet. The humus component in Cold Desert soils is usually nil, but in the Polar Desert soils it is commonly as much as 1% to 2% or higher, especially in medium?]textured soils. Whether there are enough distinct differences between the two soils to recognize two different categories remains somewhat moot. After equating all information, however, one appears to be justified in tentatively recognizing two distinct soils.

There has lately been a growth in the number and level of studies of contourite deposits. Most recent studies of contourites have two major lines of interest. One, propelled by the oil industry's continuous move into increasingly deep waters, concerns their economic significance. The other involves the stratigraphic/ palaeoceanographic record of ocean circulation changes imprinted on contourite deposits that can be a key to understanding better the climate-ocean connection. The application of many different theoretical, experimental and empirical resources provided by geophysics, sedimentology, geochemistry, petrology, scale modeling and field geology are used in the 16 papers of this volume, proposing answers to those two main aspects. The papers are subdivided into two major categories (economic interest and stratigraphic/palaeoceanographic significance), with case studies ranging from well-documented drifts to new examples of modern and fossil series, involving a large diversity of geographic and physiographic scenarios worldwide

Late Cenozoic glaciation directly affected sedimentation on more than half the Earth's continental shelves. Ice continues to be a dominant influence on sedimentation around Greenland and Antarctica, and on the shelves facing the Arctic Ocean. The features of these shelves include true glacimarine features, i.e. those found in a marine environment in proximityto, or strongly under the influence of, ice, such as iceberg scours and pits, ice gouges and incisions, subglacial outwash deposits, and diamictons resulting from ice rafting. Also seen, because large areas of the shelves were exposed during the Pleistocene lowering of sea level, are terrestrial glacial and periglacial features, e.g. fluvial outwash valleys and associated deposits, tunnel valleys, drumlin fields and lodgement till, which have subsequently been submerged and modified by marine influences. Glaciated Continental Margins: An Atlas of Acoustic Images illustrates the complexity of features found in glaciated and formerly glaciated marine environments. The volume was assembled by an international Editorial Committee, led by Thomas A. Davies (University of Texas), from records gathered in the course of recent research and contributed by members of the scientific community from around the world. These include seismic sections, side-scan maps, and 3-D seismic data, supplemented in some cases by bottom photographs and core data, with accompanying text. The work is scientists at 40 institutions in 10 countries is represented. This book will be an invaluable resource for students, Quaternary scientists, glaciologists, marine geologists and geophysicists, geotechnical engineers, and surveyors teachers working in universities, research institutions and government agencies with interests in polar and subpolar regions, as well as those in industries with offshore interests.

A comprehensive single-authored book to introduce students and researchers to the marine geology of the Antarctic.

Antarctica is the center from which all surrounding continental bodies separated millions of years ago. Antarctica: A Keystone in a Changing World, reinforces the importance of continual changes in the country's history and the impact of these changes on global systems. The book also places emphasis on deciphering the climate records in ice cores, geologic cores, rock outcrops and those inferred from climate models. New technologies for the coming decades of geoscience data collection are also highlighted. Antarctica: A Keystone in a Changing World is a collection of papers that were presented by keynote speakers at the 10th International Symposium on Antarctic Earth Sciences. It is of interest to policy makers, researchers and scientific institutions.