Influence of rapid glacial retreat on the rate of erosion by tidewater glaciers PDF Download

Author: M.N. KOPPES
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Katherine V. Boldt
Publisher:
ISBN:
Category : Glacial erosion
Languages : en
Pages : 162

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Ice-ocean interactions remain poorly understood despite the growing recognition that they play significant roles in the complex behavior of glaciers that reach the oceans, which is of broad interest because it contributes substantially to the challenge of predicting global sea-level rise. This research focuses on the dynamics of sediment accumulation near the calving fronts of tidewater glaciers across a climatic continuum from polar to temperate conditions. Rates and spatial patterns of sediment accumulation merit close attention because they can affect glacier stability by reducing the water depth that controls the calving rate, the surface area available for submarine melting, and the ability of tidewater glaciers to advance into deep water. The sediments produced by these glaciers are also of considerable interest because they record changes in glacial, environmental, and tectonic conditions. In light of the recent, well documented changes in climate and glacier extent along the Antarctic Peninsula through much of the last century, a detailed study was developed to understand how modern sediments have recorded these regional changes. Sediment accumulation rates for sixteen cores collected in fjords across a 15° N-S transect from the Antarctic Peninsula to southern Chile were calculated using the decay of naturally occurring radioisotope 210Pb. Records from the Antarctic Peninsula show surprisingly constant rates of sediment accumulation (1-7 mm/yr) throughout the past century despite rapid warming, increase in surface melt, and glacial retreat. Cores from the South Shetland Islands, on the other hand, reveal accelerated sediment accumulation over the past few decades, likely due to warming and an increase in surface melt in this region, which straddles the boundary between subpolar and temperate conditions. In the temperate fjords of southern Chile, sediment accumulates faster (11-24 mm/yr). This increase in sediment accumulation with decreasing latitude reflects the gradient from subpolar to temperate climates, and is consistent with glacial erosion being much faster in the very wet, temperate climate of southern Chile than along the colder Antarctic Peninsula. Links between rates of glacier retreat, ice motion, sediment flux, and the evolution of glacial sediment deposits in a temperate setting are explored using a large existing dataset for Columbia Glacier, Alaska and new oceanographic data from the fjord recently exposed by its retreat. High-resolution seismic data indicate that 3.2 x 108 m3 of sediment has accumulated over the last three decades; this volume corresponds to erosion at 5.1 ± 1.8 mm/yr averaged over the entire ~1000 km2 area of the glacier. A numerical model is developed to relate known patterns of sedimentation and changes in the glacier terminus position to the accumulation of sediment in the fjord during the 30-year period of retreat. The model, which represents both primary sedimentation and secondary reworking, is used to produce a history of the sediment flux from the glacier that is compatible with the observed post-retreat sediment deposit thickness and architecture. The bathymetric history and model results corroborate that the sediment flux increased sixfold within the 1997-2000 period; interestingly this increase is not correlated with concurrent changes in glacier dynamics. It is suggested that the increase resulted from the sediment transport capacity of subglacial rivers increasing due to the retreat-related steepening of the glacier surface over a deep subglacial basin. That major variations in the sediment flux can be controlled by changes in subglacial sediment storage, in addition to changes in climate and the erosion rate, adds richness and complexity to the interpretation of the glacimarine sediment record. The sediment-flux model is also applied to Jorge Montt Glacier, a Patagonian tidewater glacier with very similar behavior to Columbia Glacier, but without the detailed record of its retreat history and other complementary glaciological data. Sediment volume calculations for both glaciers indicate that the effective erosion rate necessary to sustain the mean sediment fluxes during their respective periods of retreat is surprisingly similar, ~5 mm/yr, despite differences in the geographic, tectonic, and geologic settings. For both rapidly retreating glaciers, the numerical model yields a sediment-flux history that produces sediment packages generally consistent with observed bathymetry and internal stratigraphic architecture. On the time scale of retreat, temporal variations in the modeled sediment flux from both glaciers are not related to concurrent variations in ice velocity, as expected. Rather, changes in the sediment flux are attributed to the tendency for sediment to be flushed from subglacial basins due to the progressive steepening of the glacier terminus during retreat. In both fjords, model results corroborate that sediment accumulates rapidly (>1 m/yr) near the ice front. In addition, the model suggests that gravity-driven processes are essential for delivering and redistributing sediment within the fjords to create the observed bathymetry and internal stratigraphic architecture.

Author: Michèle Nathalie Koppes
Publisher:
ISBN:
Category : Glacial erosion
Languages : en
Pages : 80

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Author: Michael Z. Li
Publisher: John Wiley & Sons
ISBN: 144435082X
Category : Science
Languages : en
Pages : 442

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The application of multibeam and sediment transport measurement technologies and the adoption of multi-faceted research methodologies have greatly advanced our understanding of the sedimentary processes on continental shelves in the last decade. This book uniquely blends cutting-edge research and state-of-the art review articles that take stock of new advances in multibeam mapping and sediment transport technologies, spatial analysis and modelling, and the applications of these advances to the understanding of shelf sediments, morphodynamics, and sedimentary processes. Case studies are also presented to illustrate the utilization of seabed property and process knowledge in habitat mapping and ocean management With its mix of papers focusing on technological advances, integration of shelf morphology and processes, and the application of these advances to coastal and ocean management, this Special Publication volume will serve as a milestone reference for professional marine scientists and as advanced text for students in marine geology, sedimentology and oceanography. This book is part of the International Association of Sedimentologists (IAS) Special Publications. The Special Publications from the IAS are a set of thematic volumes edited by specialists on subjects of central interest to sedimentologists. Papers are reviewed and printed to the same high standards as those published in the journal Sedimentology and several of these volumes have become standard works of reference.

Author: Vijay P. Singh
Publisher: Springer Science & Business Media
ISBN: 904812641X
Category : Science
Languages : en
Pages : 1301

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The earth’s cryosphere, which includes snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost, contains about 75% of the earth’s fresh water. It exists at almost all latitudes, from the tropics to the poles, and plays a vital role in controlling the global climate system. It also provides direct visible evidence of the effect of climate change, and, therefore, requires proper understanding of its complex dynamics. This encyclopedia mainly focuses on the various aspects of snow, ice and glaciers, but also covers other cryospheric branches, and provides up-to-date information and basic concepts on relevant topics. It includes alphabetically arranged and professionally written, comprehensive and authoritative academic articles by well-known international experts in individual fields. The encyclopedia contains a broad spectrum of topics, ranging from the atmospheric processes responsible for snow formation; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide distribution; glaciation and ice ages; glacier dynamics; glacier surface and subsurface characteristics; geomorphic processes and landscape formation; hydrology and sedimentary systems; permafrost degradation; hazards caused by cryospheric changes; and trends of glacier retreat on the global scale along with the impact of climate change. This book can serve as a source of reference at the undergraduate and graduate level and help to better understand snow, ice and glaciers. It will also be an indispensable tool containing specialized literature for geologists, geographers, climatologists, hydrologists, and water resources engineers; as well as for those who are engaged in the practice of agricultural and civil engineering, earth sciences, environmental sciences and engineering, ecosystem management, and other relevant subjects.

Author: Intergovernmental Panel on Climate Change (IPCC)
Publisher: Cambridge University Press
ISBN: 9781009157971
Category : Science
Languages : en
Pages : 755

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The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.

Author: Wilfried Haeberli
Publisher: Elsevier
ISBN: 0128171308
Category : Science
Languages : en
Pages : 786

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Snow and Ice-Related Hazards, Risks, and Disasters, Second Edition, provides you with the latest scientific developments in sea level rise, permafrost degradation, rock/ice avalanches, glacier surges, glacial lake outburst floods, ice shelf collapses, climate change implications, causality, impacts, preparedness and mitigation. The book takes a geo-scientific approach to the topic while also covering current thinking about directly related social scientific issues that can affect ecosystems and global economies. Special emphasis is placed on the rapidly progressing effects from global warming on the cryosphere, perspectives for the future and latest scientific advances, and technological developments. - Presents the latest research on causality, glacial surges, ice-shelf collapses, sea level rise, climate change implications, and more - Contains numerous tables, maps, diagrams, illustrations and photographs of hazardous processes - Features new insights on the implications of climate change, including increased melting, collapsing, flooding, methane emissions, and sea level rise

Author: Carina Hoorn
Publisher: John Wiley & Sons
ISBN: 111915989X
Category : Science
Languages : en
Pages : 595

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Mountains, Climate and Biodiversity: A comprehensive and up-to-date synthesis for students and researchers Mountains are topographically complex formations that play a fundamental role in regional and continental-scale climates. They are also cradles to all major river systems and home to unique, and often highly biodiverse and threatened, ecosystems. But how do all these processes tie together to form the patterns of diversity we see today? Written by leading researchers in the fields of geology, biology, climate, and geography, this book explores the relationship between mountain building and climate change, and how these processes shape biodiversity through time and space. In the first two sections, you will learn about the processes, theory, and methods connecting mountain building and biodiversity In the third section, you will read compelling examples from around the world exploring the links between mountains, climate and biodiversity Throughout the 31 peer-reviewed chapters, a non-technical style and synthetic illustrations make this book accessible to a wide audience A comprehensive glossary summarises the main concepts and terminology Readership: Mountains, Climate and Biodiversity is intended for students and researchers in geosciences, biology and geography. It is specifically compiled for those who are interested in historical biogeography, biodiversity and conservation.

Author:
Publisher: Academic Press
ISBN: 0123964733
Category : Nature
Languages : en
Pages : 787

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Snow and Ice-Related Hazards, Risks, and Disasters provides you with the latest scientific developments in glacier surges and melting, ice shelf collapses, paleo-climate reconstruction, sea level rise, climate change implications, causality, impacts, preparedness, and mitigation. It takes a geo-scientific approach to the topic while also covering current thinking about directly related social scientific issues that can adversely affect ecosystems and global economies. Puts the contributions from expert oceanographers, geologists, geophysicists, environmental scientists, and climatologists selected by a world-renowned editorial board in your hands Presents the latest research on causality, glacial surges, ice-shelf collapses, sea level rise, climate change implications, and more Numerous tables, maps, diagrams, illustrations and photographs of hazardous processes will be included Features new insights into the implications of climate change on increased melting, collapsing, flooding, methane emissions, and sea level rise

Author: Johansen, Kari Synnove
Publisher: UNESCO Publishing
ISBN: 9231002864
Category : Education
Languages : en
Pages : 80

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This Atlas illustrates the significant reduction in glacier mass happening throughout the Andean region. It quantifies the contribution of glaciers to drinking water supplies in cities and to agriculture, hydropower and industries. A reduction in glacier mass results in a long-term reduction in seasonal melt water - which is the mainstay of livelihoods for millions of people.