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 0 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 Quaternary Glaciations Extent and Chronology written by J. Ehlers and published by Elsevier. This book was released on 2004-10-02 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the second of three volumes in which the recent knowledge of the extent and chronology of Quaternary glaciations has been compiled on a global scale. This information is seen as a fundamental requirement, not only for the glacial community, but for the wider user-community of general Quaternary workers. In particular the need for accurate ice-front positions is a basic requirement for the rapidly growing field of palaeoclimate modelling. In order to provide the information for the widest-possible range of users in the most accessible form, a series of digital maps was prepared.The glacial limits were mapped in ArcView, the Geographical Information System (GIS) used by the work group. Included with the publication is a CD with digital maps, showing glacial limits, end moraines, ice-dammed lakes, glacier-induced drainage diversions and the locations of key sections through which the glacial limits are defined and dated. The last deglaciation is also shown in 500 year time-steps. The digital maps in this volume cover the USA and Canada and include Greenland and Hawaii. Both overview maps and more detailed maps at a scale 1: 1,000,000 are provided.Also available:Part I: Europe, ISBN 0-444-51462-7Part III: South America, Asia, Africa, Australia, Antarctica, ISBN 0-444-51593-3

Download or read book Holocene Ice Sheet Dynamics and Detrital Provenance Shifts Along the West Greenland Margin written by Lina Madaj and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the effect of Arctic Amplification the Arctic is currently warming at least twice as fast as the rest of the planet. Seasonal sea-ice extent has been alarmingly declining in the past decade. Glaciers and ice caps along the Greenland coast and in the Canadian Arctic have been losing mass on an accelerated rate during the past century. As the global climate system is a complex system connecting different regions via atmospheric transport, changes in Arctic climate patterns are affecting the climate and weather conditions in the lower latitudes. The Greenland Ice Sheet as well as glaciers and ice caps in the Canadian Arctic are the largest freshwater storages on the northern hemisphere and expected to be among the highest contributors to global sea level rise. Freshwater input through meltwater discharge is not only affecting sea level rise but further influencing deep water formation in the Labrador Sea and the subpolar North Atlantic and hence global ocean circulation and climate patterns. To be able to sufficiently predict future developments of the Greenland Ice Sheet with respect to mass loss and resulting impacts on the global climate, data from past climate and Greenland Ice Sheet extents are crucially important. The Holocene spanning the last period of the deglaciation after the Last Glacial Maximum culminating in the Holocene Thermal Maximum when atmospheric temperatures were warmer and glacier and ice-sheet extent smaller than today represents the closest analogue to current atmospheric warming and Greenland Ice Sheet mass loss. The wide west Greenland shelf of Baffin Bay and Labrador Sea hosts thick marine sediments archiving around ten thousand years of this past climate and ice-sheet history. Siliciclastic detrital material discharged into Baffin Bay and the Labrador Sea via meltwater and erosion can be separated from those sedimentary archives and traced back to its source region. Radiogenic isotopes (Sr, Nd, Pb) label the source regions of those sediments by fingerprinting the isotopic composition of the prevailing bedrock. Hence, they can be used as reliable provenance tracers. Retreating land-ice masses expose bedrock that before was not subject to erosion, influencing the isotopic signatures delivered into the surrounding ocean. Based on this theory, radiogenic isotopes can record changes in siliciclastic detrital sediment provenance and hence, indirectly trace ice-sheet dynamics. The overall aim of this thesis work is to reconstruct changes in detrital sediment provenance along the west Greenland shelf to gain new insights into Holocene Greenland Ice Sheet dynamics and ocean current-induced sediment transport. Sedimentary archives from three main research areas (eastern Labrador Sea, northeastern Baffin Bay, and Kane Basin, central Nares Strait) record obvious shifts in sediment provenance throughout the Holocene. Those shifts coincide with major regional climatic changes in the research area. Generally, all records reveal the local bedrock as the main source region of detrital material and distal-sourced material transported along the coast via the West Greenland Current as a secondary source. Although the proportion of distal sourced material appears to be small, changes in West Greenland Current strength have been recorded in the isotopic composition. In southwestern Greenland and the Labrador Sea radiogenic isotope records reveal a shift towards a higher proportion of the local Archean Block in the late Holocene caused by Neoglacial ice advance and a reduction in West Greenland Current speed delivering less material from southern most Greenland. Farther north in the Upernavik region, midwest Greenland coast, the isotopic composition marks a change with the transition from early to mid Holocene caused by increased West Greenland Current strength and the opening of Vaigat Strait which enabled erosion and transport of freshly exposed basalts from the Disko Bay area due to ice-sheet retreat. This basalt input is, however, not transported all the way to northernmost Melville Bay (northern Baffin Bay) where the detrital sediment composition is clearly dominated by contribution of the local Committee-Melville Belt without any significant provenance changes throughout the Holocene. Farthest north, the sedimentary record from Kane Basin records provenance shifts that confirm the opening of Nares Strait around 8.3 ka BP. This event is followed by an increased delivery of carbonate-rich detrital sediments from northern Ellesmere Island due to the newly established gateway of Arctic Ocean water transporting sediments from further north to the core location. Additionally determined mineralogical composition of the sedimentary records along the west Greenland coast supports the interpretation drawn from the radiogenic isotopic composition. Furthermore, it points out the additional value of radiogenic isotopes through variations only visible in isotopic composition but not in the mineralogical composition. Further comparison to other studies from the region based on different tracers confirms the reliability and sufficient application of radiogenic isotopes in provenance studies as well as the advantage of multi-proxy approaches in paleoclimatological studies. Overall, this study highlights the advantages and reliability of radiogenic isotopes in provenance studies with regards to reconstructions of ice-sheet dynamics. The combination of the three isotopic systems (Sr, Nd, Pb) enables source region determination with a higher probability compensating for overlapping signatures within individual isotopic systems. The transect of sedimentary records along the west Greenland coast identifies clearly distinguishable isotopic ranges for the different Greenland bedrock terrains, qualifying this approach for further high-resolution investigation in past Greenland Ice Sheet development.

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 Holocene Ice Margin Fluctuations of the Greenland Ice Sheet in the Disko Bugt Region West Greenland written by and published by . This book was released on 2014 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current response of the Greenland Ice Sheet (GrIS) margin to climate change is spatially and temporally variable. Understanding the mechanisms that control this variability is crucial for accurate predictions of how the GrIS will change in the future. One factor that appears to play a role in driving the varying response exhibited along the margin of the GrIS is the ice margin setting (marine-terminating or land-terminating). Recent research has demonstrated that basal melting of marine-terminating glaciers may increase their vulnerability to climatic perturbations, while their land-terminating counterparts may lag in their reaction similar climatic changes. While these trends are illustrated in historic and modern records, longer temporal records are needed to place these observations in context. Here, I present a chronology of GrIS fluctuations within the Disko Bugt region of West Greenland. This record spans the Holocene, and is constrained by 10Be and radiocarbon ages. Through building this chronology, I reconstruct the pattern and timing of Holocene ice margin fluctuations and evaluate the response of differing ice margin types (marine-based or land-based) to regional climate forcing. From my chronology it is apparent that, on millennial timescales early Holocene ice margin retreat rates were synchronous within Disko Bugt. This pattern extends along the western margin of the GrIS, with all the sections of the ice margin examined displaying similar retreat rates despite dissimilar marginal settings. This is strikingly different than modern trends, where marine-based outlet glaciers exhibit significantly higher retreat rates than their land-based counterparts. The record of ice margin reaction to recent warming demonstrates a distinct pattern of asynchrony. In my late Holocene records, marine-based glaciers initiate retreat much sooner than land-based sectors of the ice margin. I believe this feature demonstrates a relationship between ice margin type and response time. I propose that in West Greenland faster glaciers maintain a closer equilibrium with changing climate than slower flowing glaciers. In total, the historic pattern of relative stability of land-based sectors of the GrIS is in contrast with the longer records of Holocene ice margin fluctuation. Additionally, a relationship between ice margin type and response time suggests that land-based sectors of the ice margin lag in their reaction to climate forcing on decadal scales. This indicates that historically stable sectors of the ice margin may be expected to undergo significant future retreat, as a larger percentage of the GrIS margin begins to react to 20th century warming.

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 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 European Glacial Landscapes written by David Palacios and published by Elsevier. This book was released on 2023-10-21 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: European Glacial Landscapes: The Holocene presents the current state of knowledge on glacial landscapes of Europe and nearby areas over the Holocene to deduce the influence of atmospheric and oceanic currents and the insolation forcing variability and volcanic activity on Holocene paleoclimates, the existence of asynchronies in the timing of occurrence of glacier expansion and shrinkage during the Holocene, time lags between the identification of oceanic and atmospheric changes and those occurring in glacial extension during the Holocene, the role of Holocene glaciers on the climate of Europe, and on sea level variability, and the delimitation of landscapes that need special protection. Students, academics and researchers in Geography, Geology, Environmental Sciences, Physics and Earth Science departments will find this book provides novel findings of all the major European Regions in a single publication, with updated information about Holocene glacial geomorphology and paleo-climatology and clear figures that model the landscapes covered. Provides a synthesis and summary of glacial processes in Europe over the Holocene period Features research from experts in palaeo-climatology, palaeo-oceanography and palaeo-glaciology Includes access to a companion website with an interactive map, photos of glacial features, and geospatial data related to European Glacial Landscapes

Download or read book Antarctic Climate Evolution written by Fabio Florindo and published by Elsevier. This book was released on 2008-10-10 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antarctic Climate Evolution is the first book dedicated to furthering knowledge on the evolution of the world's largest ice sheet over its ~34 million year history. This volume provides the latest information on subjects ranging from terrestrial and marine geology to sedimentology and glacier geophysics. - An overview of Antarctic climate change, analyzing historical, present-day and future developments - Contributions from leading experts and scholars from around the world - Informs and updates climate change scientists and experts in related areas of study

Download or read book Holocene History of the Greenland Ice Sheet Based on Radio carbon dated Moraines in West Greenland written by Norman W. Ten Brink and published by . This book was released on 1975 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Untangling the Quaternary Period written by Richard B. Waitt and published by Geological Society of America. This book was released on 2021-04-20 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume brings together nineteen papers of interdisciplinary Quaternary science honoring Stephen Porter. Special Paper 548 features papers from six continents, on wide-ranging topics including glaciation, paleoecology, landscape evolution, megafloods, and loess. The topical and geographical range of the papers, as well as their interdisciplinary nature, honor Porter's distinct approach to Quaternary science and leadership that influence the field to this day"--

Download or read book Quaternary Dating Methods written by Mike Walker and published by John Wiley & Sons. This book was released on 2013-04-30 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introductory textbook introduces the basics of dating, the range of techniques available and the strengths and limitations of each of the principal methods. Coverage includes: the concept of time in Quaternary Science and related fields the history of dating from lithostratigraphy and biostratigraphy the development and application of radiometric methods different methods in dating: radiometric dating, incremental dating, relative dating and age equivalence Presented in a clear and straightforward manner with the minimum of technical detail, this text is a great introduction for both students and practitioners in the Earth, Environmental and Archaeological Sciences. Praise from the reviews: "This book is a must for any Quaternary scientist." SOUTH AFRICAN GEOGRAPHICAL JOURNAL, September 2006 “...very well organized, clearly and straightforwardly written and provides a good overview on the wide field of Quaternary dating methods...” JOURNAL OF QUATERNARY SCIENCE, January 2007

Download or read book Early Middle Pleistocene Transitions written by Geological Society of London and published by Geological Society of London. This book was released on 2005 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Early-Middle Pleistocene transition (around 1.2 to 0.5 Ma) marks a profound shift in Earth's climate state. Low-amplitude 41 ka climate cycles, dominating the earlier part of the Pleistocene, gave way progressively to a 100 ka rhythm of increased amplitude that characterizes our present glacial-interglacial world. This volume assesses the biotic and physical response to this transition both on land and in the oceans: indeed it examines the very nature of Quaternary climate change. Milankovitch theory, palaeoceanography using isotopes and microfossils, marine organic geochemistry, tephrochronology, the record of loess and soil deposition, terrestrial vegetational change, and the migration and evolution of hominins as well as other large and small mammals, are all considered. These themes combine to explore the very origins of our present biota.

Download or read book Antarctic Peninsula Climate Variability written by Eugene Domack and published by American Geophysical Union. This book was released on 2003-01-10 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 79. The Antarctic Peninsula region represents our best natural laboratory to investigate how earth's major climate systems interact and how such systems respond to rapid regional warming. The scale of environmental changes now taking place across the region is large and their pace rapid but the subsystems involved are still small enough to observe and accurately document cause and affect mechanisms. For example, clarification of ice shelf stability via the Larsen Ice Shelf is vital to understanding the entire Antarctic Ice Sheet, its climate evolution, and its response to and control of sea level. By encompassing the broadest range of interdisciplinary studies, this volume provides the global change research and educational communities a framework in which to advance our knowledge of the causes behind regional warming, the dramatic glacial and ecological responses, and the potential uniqueness of the event within the region's paleoclimate record. The volume also serves as a vital resource for public policy and governmental funding agencies as well as a means to educate the large number of ecotourists that visit the region each austral summer.

Download or read book The Glacial World According to Wally written by Wallace S. Broecker and published by . This book was released on 1995 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atlas of Submarine Glacial Landforms written by J.A. Dowdeswell and published by Geological Society of London. This book was released on 2016-12-16 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: New geophysical techniques (multibeam echo sounding and 3D seismics) have revolutionized high-resolution imaging of the modern seafloor and palaeo-shelf surfaces in Arctic and Antarctic waters, generating vast quantities of data and novel insights into sedimentary architecture and past environmental conditions. The Atlas of Submarine Glacial Landforms is a comprehensive and timely summary of the current state of knowledge of these high-latitude glacier-influenced systems. The Atlas presents over 180 contributions describing, illustrating and discussing the full variability of landforms found on the high-latitude glacier-influenced seafloor, from fjords and continental shelves to the continental slope, rise and deep-sea basins beyond. The distribution and geometry of these submarine landforms provide key information on past ice-sheet extent and the direction and nature of ice flow and dynamics. The papers discuss individual seafloor landforms, landform assemblages and entire landsystems from relatively mild to extreme glacimarine climatic settings and on timescales from the modern margins of tidewater glaciers, through Quaternary examples to ancient glaciations in the Late Ordovician.

Download or read book The Vegetation of Antarctica through Geological Time written by David J. Cantrill and published by Cambridge University Press. This book was released on 2012-11-22 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fossil history of plant life in Antarctica is central to our understanding of the evolution of vegetation through geological time and also plays a key role in reconstructing past configurations of the continents and associated climatic conditions. This book provides the only detailed overview of the development of Antarctic vegetation from the Devonian period to the present day, presenting Earth scientists with valuable insights into the break up of the ancient supercontinent of Gondwana. Details of specific floras and ecosystems are provided within the context of changing geological, geographical and environmental conditions, alongside comparisons with contemporaneous and modern ecosystems. The authors demonstrate how palaeobotany contributes to our understanding of the paleoenvironmental changes in the southern hemisphere during this period of Earth history. The book is a complete and up-to-date reference for researchers and students in Antarctic paleobotany and terrestrial paleoecology.