Download or read book Late Quaternary Ice ocean Interactions in Central West Greenland written by David John McCarthy and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A greater knowledge of the interactions between the Greenland Ice Sheet and climate is critical to understanding the possible impacts of future global warming, including ice sheet contribution to global sea-level rise and perturbations to ocean circulation. Recent acceleration, thinning and retreat of major tidewater glaciers in Greenland and Antarctica during the past two decades demonstrate the potential for ice sheets to respond to climate change much faster than previously assumed. One approach to understanding the role of atmospheric and oceanic warming to ice sheet dynamics is to investigate how ice sheets responded to past periods of climate change. This thesis uses benthic foraminifera as a proxy to reconstruct past changes in the temperature of the relatively warm West Greenland Current, to investigate the possible influence of ocean warming on ice sheet dynamics during the initial marine-based deglaciation phase, and throughout the Holocene, when the ice was positioned close to the present margin. This thesis finds that the marine-based ice sheet in central West Greenland collapsed rapidly due to a combination of high relative sea-level and ice sheet thinning due to climatic warming. Foraminiferal evidence does not support a major influence of ocean forcing on initial deglaciation. However, Holocene changes in the relative temperature of the West Greenland Current may have had a more significant influence on ice stream dynamics following the marine-based ice retreat, when outlet glaciers were positioned within coastal fjords. Changes in the relative temperature of the West Greenland Current are determined?upstream? by wider scale changes in the North Atlantic region.
Download or read book Ice Drift Ocean Circulation and Climate Change written by Jens Bischof and published by Springer Science & Business Media. This book was released on 2000-11 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The issue of global warming and climate change is of continuous concern. Since the 1970s, it bas been shown that the pack-ice around the Arctic Ocean is thinning, the margin of permafrost is moving north and the vegetation in the high northern parts of the world is changing (the 'greening' of the Arctic). But are these changes the result of human activity or simply regular variations of the Earth's climate system? Over thousands of years, a continuous archive of iceberg and sea ice drift bas formed in the deep-sea sediments, revealing the place of the ice's origin and allowing a reconstruction of the surface currents and the climate of the past. However, the drift of floating ice from one place to another is not just a passive record of past ocean circulation. It actively influences and changes the surface ocean circulation, thus having a profound effect on climate change. Ice Drift, Ocean Circulation and Climate Change is the first book to focus on the interactions between ice, the ocean and the atmosphere and to describe how these three components of the climate system influence each other. It makes clear the positive contribution of paleoclimatology and paleoceanography and should be read by anyone concerned with global warming and climate change.
Download or read book A Chronology of Late Quaternary Southwestern Greenland Ice Sheet Retreat Using Terrestrial and Marine Records written by and published by . This book was released on 2014 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation examines forcings of southwestern Greenland ice sheet (GrIS) retreat, and the time-scale of ice response to these drivers. Using sediment grain size analyses, planktic foraminifera Neogloboquadrina pachyderma (s) [delta]18O, and planktic foraminifera 14C for southeastern Davis Strait sediment core HU87033-008, early last deglaciation ice retreat is reconstructed. A peak in sediment flux 19-18 ka suggests a southwestern GrIS margin at or near the continental shelf break. Rapid retreat to the middle or inner shelf occurred by 17 ka. This timing, prior to deglacial warming in the region, points to sea level rise as the primary forcing on southwestern GrIS retreat from the outer shelf, over ~1,000 years. Following this early deglacial retreat, the southwestern GrIS maintained a shelf position until withdrawing inland of the modern coastline at 12-11 ka. Ice thinning rates at the coastline from high to low elevations, and retreat inland to the modern ice margin, are calculated using 10Be surface exposure dates from boulders along four transects. Three transects experienced strong marine influence due to extensive fjord systems, whereas the fourth transect experienced weak marine influence. Data from this dissertation demonstrates that thinning and retreat occurred quickly at the sites with marine-terminating ice between 12 and 10.5 ka, concurrent with the rise in Labrador Sea temperatures from glacial-like to interglacial-like conditions. Slow retreat rate at the land-terminating ice margin suggests that warming ocean waters were the dominant forcing on late deglacial retreat of marine-terminating outlet glaciers, which occurred over centuries to ~1,000 years. After the last deglaciation, the GrIS continued to retreat inland, then readvanced during the cooler climate of 4-0.1 ka. The maximum ice position of this late Holocene period is generally considered to be during the Little Ice Age (0.6-0.1 ka). However, 10Be surface exposure dating of boulders associated with the Narsarsuaq moraine in southern Greenland places the maximum ice extent of the Kiagtût sermiat glacier at 1.5 ka. In combination with nearby paleoclimate records, this suggests that southern Greenland may have experienced different temperature trends than that of western Greenland or northwestern Europe, driving ice response on a centennial-scale.
Download or read book Late Quaternary Stratigraphy and Glaciology in the Thule Area Northwest Greenland written by Svend Funder and published by Museum Tusculanum Press. This book was released on 1990 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Late Quaternary Palaeoceanography of the North Atlantic Margins written by John T. Andrews and published by Geological Society of London. This book was released on 1996 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this book is on oceanic climate change during the last deglaciation period and the high temporal resolution that can be obtained from sediment records at continental margin sites. The book draws together papers from the north-eastern North American continental margin with those from the north-west European Arctic and the Arctic and North Atlantic Oceans.
Download or read book Quaternary Geology of Western and Central North Greenland written by Michael Kelly and published by . This book was released on 1992 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Late Glacial and Holocene Fluctuations of Local Glaciers and the Greenland Ice Sheet Eastern and Western Greenland written by Laura B. Levy and published by . This book was released on 2014 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Greenland Ice Sheet (GrIS) is responding sensitively to climate change and its meltwater has the potential to influence global sea level. Recently, large changes in the GrIS have occurred including increased velocities of outlet glaciers and melt over ~97% of the ice sheet. One means to understand modern and help predict future changes in the GrIS is to examine how it responded to past climate conditions. In this dissertation I provide a longer-term perspective of changes in the GrIS as well as in smaller, independent glaciers near the ice sheet margins (i.e., "local" glaciers). My research documents the past extents of the GrIS in central East and southern West Greenland during the Holocene Epoch (11,600 yrs ago-present) and provides evidence for climate conditions along the ice sheet margin during late glacial time (~17,500-11,600 yrs ago) and the Holocene Epoch. I use geomorphic mapping, surface exposure dating and lake sediment analyses to demonstrate that the GrIS and local glaciers in central East Greenland were receding during the Younger Dryas cold event (~12,900-11,600 yrs ago) and deposited the Milne Land stade moraines at the end of the Younger Dryas. I hypothesize that these ice marginal fluctuations were primarily influenced by air or ocean surface temperatures. I document the Holocene fluctuations of a local glacier that completely disappeared indicating peak warm conditions between ~9.3 and 6.0 cal kyr BP. The formation of this glacier at 2.6 cal kyr BP and its persistence from ~1.9 cal kyr BP-present suggests cold conditions during late Holocene time. I also use geomorphic mapping and surface exposure dating to document the extents of the GrIS in southern West Greenland, near Kangerlussuaq. I show that the Keglen, Ørkendalen and Historical moraines were deposited at 7.3 ka, 6.3 ka, and by ~AD 1950, respectively. These data indicate that the GrIS was as small as or smaller than at present during much of middle to late Holocene time. Finally, I synthesize my results and discuss possible causes of GrIS marginal changes in central East and southern West Greenland including changes in air and ocean temperatures and changes in sea level."
Download or read book Holocene Interaction Between Ocean Circulation and the West Greenland Ice Sheet written by Kerstin Perner and published by . This book was released on 2012 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quaternary ice sheet ocean interactions and landscape responses written by and published by . This book was released on 2009 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quaternary Glaciations Extent and Chronology written by J. Ehlers and published by Elsevier. This book was released on 2011-08-17 with total page 1128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents an up-to-date, detailed overview of the Quaternary glaciations all over the world, not only with regard to stratigraphy but also with regard to major glacial landforms and the extent of the respective ice sheets. The locations of key sites are included. The information is presented in digital, uniformly prepared maps which can be used in a Geographical Information System (GIS) such as ArcView or ArcGIS. The accompanying text supplies the information on how the data were obtained (geomorphology, geological mapping, air photograph evaluation, satellite imagery), how the features were dated (14C, TL, relative stratigraphy) and how reliable they are supposed to be. All references to the underlying basic publications are included. Where controversial interpretations are possible e.g. in Siberia or Tibet, this is pointed out. As a result, the information on Quaternary glaciations worldwide will be much improved and supplied in a uniform digital format. The information on the glacial limits is compiled in digital form by the coordinators of the project, and is available for download at: http://booksite.elsevier.com/9780444534477/ Completely updated detailed coverage of worldwide Quaternary glaciations Information in digital, uniformly prepared maps which can be used in a GIS such as ArcView or ArcGis Step-by-step guideline how to open and use ArcGis files Possibility to convert the shapefiles into GoogleEarth kmz-files Availability of chronological controls
Download or read book Glacier Science and Environmental Change written by Peter G. Knight and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glacier Science and Environmental Change is an authoritative and comprehensive reference work on contemporary issues in glaciology. It explores the interface between glacier science and environmental change, in the past, present, and future. Written by the world’s foremost authorities in the subject and researchers at the scientific frontier where conventional wisdom of approach comes face to face with unsolved problems, this book provides: state-of-the-art reviews of the key topics in glaciology and related disciplines in environmental change cutting-edge case studies of the latest research an interdisciplinary synthesis of the issues that draw together the research efforts of glaciologists and scientists from other areas such as geologists, hydrologists, and climatologists color-plate section (with selected extra figures provided in color at www.blackwellpublishing.com/knight). The topics in this book have been carefully chosen to reflect current priorities in research, the interdisciplinary nature of the subject, and the developing relationship between glaciology and studies of environmental change. Glacier Science and Environmental Change is essential reading for advanced undergraduates, postgraduate research students, and professional researchers in glaciology, geology, geography, geophysics, climatology, and related disciplines.
Download or read book Glacial Isostasy Sea Level and Mantle Rheology written by R. Sabadini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 705 pages. Available in PDF, EPUB and Kindle. Book excerpt: by K. Lambeck, R. Sabadini and E. B08Chi Viscosity is one of the important material properties of the Earth, controlling tectonic and dynamic processes such as mantle convection, isostasy, and glacial rebound. Yet it remains a poorly resolved parameter and basic questions such as whether the planet's response to loading is linear or non-linear, or what are its depth and lateral variations remain uncertain. Part of the answer to such questions lies in laboratory observations of the rheology of terrestrial materials. But the extrapolation of such measurements from the laboratory environment to the geological environment is a hazardous and vexing undertaking, for neither the time scales nor the strain rates characterizing the geological processes can be reproduced in the laboratory. General rules for this extrapolation are that if deformation is observed in the laboratory at a particular temperature, deformation in geological environments will occur at a much reduced temperature, and that if at laboratory strain rates a particular deformation mechanism dominates over all others, the relative importance of possible mechanisms may be quite different at the geologically encountered strain rates. Hence experimental results are little more than guidelines as to how the Earth may respond to forces on long time scales.
Download or read book Late Quaternary sedimentary processes and ocean circulation changes at the Southeast Greenland margin written by A. KUIJPERS and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quaternary Climates Environments and Magnetism written by Barbara A. Maher and published by Cambridge University Press. This book was released on 1999-12-13 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Quaternary has been a period of major climatic and environmental oscillations, and our knowledge of these past variations is important for our understanding of the possible impact of human activity on the present-day environment. First published in 1999, Quaternary Climates, Environments and Magnetism presents an account of the rich variety of uses of magnetic measurements in the environmental geosciences. Ten chapters by leading world authorities describe the highlights of environmental magnetic work during the last decade and identify directions for future research. Emphasis is placed on a multidisciplinary approach to achieve a more thorough understanding of the environmental processes involved. This volume will be of interest to research scientists from a wide range of disciplines working on Quaternary environments, including earth and environmental sciences, physical geology, geography and palaeoclimatology. It will also be valuable as a supplementary text for graduates and advanced undergraduates.
Download or read book Polar Environments and Global Change written by Roger G. Barry and published by Cambridge University Press. This book was released on 2018-08-09 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surveys atmospheric, oceanic and cryospheric processes, present and past conditions, and changes in polar environments.
Download or read book Glacimarine Environments written by J. A. Dowdeswell and published by . This book was released on 1990 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume examines the processes responsible for sedimentation in modern glaciomarine environments, and how such modern studies can be used as analogues in the interpretation of ancient glaciomarine sequences. Sediments released from glaciers grounded in tidewater, floating ice shelves, ice tongues, icebergs and sea ice form complex sequences governed by glaciological, oceanographic, sedimentary and biogenic controls. Ten per cent of the world's oceans and epicontinental seas contain such active glacimarine environments, but during Cenozoic glacial periods this area was doubled. This book will, therefore, be of relevance to all scientists concerned with high and middle latitude marine environments. The early chapters are concerned largely with processes of sedimentation in modern glacimarine environments; examples are drawn from Alaska, the Canadian Arctic, Svalbard and Antarctica. Studies of ancient sequences, both Cenozoic and pre-Cenozoic, from the Barents Sea, Greenland, Sweden, Alaska and the northwest European continental shelf, form the latter part of the book.
