Author: Katherine V. Boldt Publisher: ISBN: Category : Glacial erosion Languages : en Pages : 162
Book Description
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: Publisher: Academic Press ISBN: 0123964733 Category : Nature Languages : en Pages : 787
Book Description
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: Bruno Latour Publisher: MIT Press ISBN: 0262044455 Category : Art Languages : en Pages : 473
Book Description
Artists and writers portray the disorientation of a world facing climate change. This monumental volume, drawn from a 2020 exhibition at the ZKM Center for Art and Media, portrays the disorientation of life in world facing climate change. It traces this disorientation to the disconnection between two different definitions of the land on which modernizing humans live: the sovereign nation from which they derive their rights, and another one, hidden, from which they gain their wealth—the land they live on, and the land they live from. Charting the land they will inhabit, they find not a globe, not the iconic “blue marble,” but a series of critical zones—patchy, heterogenous, discontinuous. With short pieces, longer essays, and more than 500 illustrations, the contributors explore the new landscape on which it may be possible for humans to land—what it means to be “on Earth,” whether the critical zone, the Gaia, or the terrestrial. They consider geopolitical conflicts and tools redesigned for the new “geopolitics of life forms.” The “thought exhibition” described in this book can opens a fictional space to explore the new climate regime; the rest of the story is unknown. Contributors include Dipesh Chakrabarty, Pierre Charbonnier, Emanuele Coccia, Vinciane Despret, Jerôme Gaillarde, Donna Haraway, Joseph Leo Koerner, Timothy Lenton, Richard Powers, Simon Schaffer, Isabelle Stengers, Bronislaw Szerszynski, Jan A. Zalasiewicz, Siegfried Zielinski Copublished with ZKM | Center for Art and Media Karlsruhe
Author: Haakon Hop Publisher: Springer ISBN: 3319464256 Category : Science Languages : en Pages : 565
Book Description
This book focuses in detail on all ecologically important aspects of the Kongsfjorden system such as the marine and atmospheric environment including long-term monitoring, Ecophysiology of individual species, structure and function of the ecosystem, ecological processes and biological communities. The contributed articles include review articles and research articles that have a wider approach and bring the current research up-to-date. This book will form a baseline for future work.
Author: James P.M. Syvitski Publisher: Springer Science & Business Media ISBN: 1461246326 Category : Science Languages : en Pages : 381
Book Description
Fjords are both an interface and a buffer between glaciated continents and the oceans. They exhibit a very wide range in environmental conditions, both in dynamics and geography. Some are truly wonders of the world with their dizzying mountain slopes rising sharply from the ocean edge. Others represent some of the harshest conditions on earth, with hurricane winds, extremes in temperature, and catastrophic earth and ice movements. Fjords are unique estuaries and represent a large portion of the earth's coastal zone. Yet they are not very well known, given the increasing population and food pressures, and their present industrial and strategic importance. Temperate zone estuaries have had many more years of intense study, with multiyear data available. Most fjords have not been impacted by man but, if history repeats itself, that condition will not last long. Fjords present some unique environmental problems, such as their usually slow flushing time, a feature common to many silled environments. Thus there is presently a need for management guidelines, which can only be based on a thorough knowledge of the way fjords work. Fjords are, in many respects, perfect natural oceanographic and geologic lab oratories. Source inputs are easily identified and their resulting gradients are well developed. Throughout this book, we emphasize the potential of modeling pro cesses in fjords, with comparisons to other estuary, lake, shelf and slope, and open ocean environments.
Author: J.A. Dowdeswell Publisher: Geological Society of London ISBN: 1786202689 Category : Science Languages : en Pages : 631
Book Description
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.
Author: Eric Wolanski Publisher: Elsevier ISBN: 0128140046 Category : Science Languages : en Pages : 730
Book Description
Coasts and Estuaries: The Future provides valuable information on how we can protect and maintain natural ecological structures while also allowing estuaries to deliver services that produce societal goods and benefits. These issues are addressed through chapters detailing case studies from estuaries and coastal waters worldwide, presenting a full range of natural variability and human pressures. Following this, a series of chapters written by scientific leaders worldwide synthesizes the problems and offers solutions for specific issues graded within the framework of the socio-economic-environmental mosaic. These include fisheries, climate change, coastal megacities, evolving human-nature interactions, remediation measures, and integrated coastal management. The problems faced by half of the world living near coasts are truly a worldwide challenge as well as an opportunity for scientists to study commonalities and differences and provide solutions. This book is centered around the proposed DAPSI(W)R(M) framework, where drivers of basic human needs requires activities that each produce pressures. The pressures are mechanisms of state change on the natural system and Impacts on societal welfare (including well-being). These problems then require responses, which are the solutions relating to governance, socio-economic and cultural measures (Scharin et al 2016). - Covers estuaries and coastal seas worldwide, integrating their commonality, differences and solutions for sustainability - Includes global case studies from leading worldwide contributors, with accompanying boxes highlighting a synopsis about a particular estuary and coastal sea, making all information easy to find - Presents full color images to aid the reader in a better understanding of details of each case study - Provides a multi-disciplinary approach, linking biology, physics, climate and social sciences
Author: John B. Anderson Publisher: Geological Society of America ISBN: 9780813722610 Category : Science Languages : en Pages : 244
Book Description
The papers in this collection are based on a symposium held at the 1988 annual meeting of the Geological Society of America, with the objective of identifying sedimentary criteria and facies models that can be used to characterize the glacial-climate setting of ancient sedimentary sequences. Includes papers on Antarctica, Alaska, and Ellesmere Island, and a brief literature review.
Author: Katherine V. Boldt
Author: Michèle Nathalie Koppes
Author: 
Author: Bruno Latour
Author: M.N. KOPPES
Author: Haakon Hop
Author: James P.M. Syvitski
Author: J.A. Dowdeswell
Author: Eric Wolanski
Author: John B. Anderson