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Glaciology Commons

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2014

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Articles 1 - 30 of 41

Full-Text Articles in Glaciology

Spring Thaw Ionic Pulses Boost Nutrient Availability And Microbial Growth In Entombed Antarctic Dry Valley Cryoconite Holes, Jon Telling, Alexandre M. Anesio, Martyn Tranter, Andrew G. Fountain, Thomas H. Nylen, Jon Hawkings, Virendra B. Singh, Preeti Kaur, Michaela Musilova, Jemma L. Wadham Dec 2014

Spring Thaw Ionic Pulses Boost Nutrient Availability And Microbial Growth In Entombed Antarctic Dry Valley Cryoconite Holes, Jon Telling, Alexandre M. Anesio, Martyn Tranter, Andrew G. Fountain, Thomas H. Nylen, Jon Hawkings, Virendra B. Singh, Preeti Kaur, Michaela Musilova, Jemma L. Wadham

Geology Faculty Publications and Presentations

The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During …


Core Handling And Processing For The Wais Divide Ice-Core Project, Joseph Souney Jr, Mark S. Twickler, Geoffrey M. Hargreaves, Brian M. Bencivengo, Matthew J. Kippenhan, Jay A. Johnson, Eric D. Cravens, Peter D. Neff, Richard M. Nunn, Anais J. Orsi, Trevor J. Popp, John F. Rhoades, Bruce H. Vaughn, Donald E. Voigt, Gifford J. Wong, Kendrick C. Taylor Dec 2014

Core Handling And Processing For The Wais Divide Ice-Core Project, Joseph Souney Jr, Mark S. Twickler, Geoffrey M. Hargreaves, Brian M. Bencivengo, Matthew J. Kippenhan, Jay A. Johnson, Eric D. Cravens, Peter D. Neff, Richard M. Nunn, Anais J. Orsi, Trevor J. Popp, John F. Rhoades, Bruce H. Vaughn, Donald E. Voigt, Gifford J. Wong, Kendrick C. Taylor

Earth Systems Research Center

On 1 December 2011 the West Antarctic Ice Sheet (WAIS) Divide ice-core project reached its final depth of 3405 m. The WAIS Divide ice core is not only the longest US ice core to date, but is also the highest-quality deep ice core, including ice from the brittle ice zone, that the US has ever recovered. The methods used at WAIS Divide to handle and log the drilled ice, the procedures used to safely retrograde the ice back to the US National Ice Core Laboratory (NICL) and the methods used to process and sample the ice at the NICL are …


Collaborative Research: Timing And Structure Of The Last Glacial Maximum And Termination In Southern Peru: Implications For The Role Of The Tropics In Climate Change, Brenda L. Hall Oct 2014

Collaborative Research: Timing And Structure Of The Last Glacial Maximum And Termination In Southern Peru: Implications For The Role Of The Tropics In Climate Change, Brenda L. Hall

University of Maine Office of Research Administration: Grant Reports

The role of the tropics in climate change has important implications for understanding both orbital-scale and abrupt climate variations. Yet our ability to assess tropical behavior during major climate events, such as the last glacial maximum (LGM), is limited by poor spatial coverage and insufficient control on sample ages. This project will address this problem by developing well-dated records of glacial fluctuations from the LGM through the termination and late-glacial period at Nevados Coropuna and Allinccapac in southern Peru and use these data in numerical simulations of glacier mass balance and local climate. These sites allow an examination of glacier …


Sensitivity Of The Antarctic Ice Sheet To Climate Change Over The Last Two Glacial/Interglacial Cycles, Brenda Hall, George H. Denton Oct 2014

Sensitivity Of The Antarctic Ice Sheet To Climate Change Over The Last Two Glacial/Interglacial Cycles, Brenda Hall, George H. Denton

University of Maine Office of Research Administration: Grant Reports

This project was designed to develop knowledge of the extent of the Ross Sea ice sheet during the last two glaciations and to develop a chronology for the last glacial maximum and penultimate glaciation. To this end, we had the following goals:

1) Map the extent of the Ross Sea ice sheet along the western coast of McMurdo Sound from Taylor Valley to the southern Royal Society Range.
2) Develop a radiocarbon chronology for the last glacial maximum from dates of algal mats within moraines.
3) Produce a uranium-thorium chronology to gain information on the timing of the penultimate glaciation. …


Sensitivity Of The Antarctic Ice Sheet To Climate Change Over The Last Two Glacial/Interglacial Cycles, Brenda L. Hall, George H. Denton Oct 2014

Sensitivity Of The Antarctic Ice Sheet To Climate Change Over The Last Two Glacial/Interglacial Cycles, Brenda L. Hall, George H. Denton

University of Maine Office of Research Administration: Grant Reports

This award supports a project to investigate the sensitivity of the Antarctic ice sheet (AIS) to global climate change over the last two Glacial/Interglacial cycles. The intellectual merit of the project is that despite its importance to Earth's climate system, we currently lack a full understanding of AIS sensitivity to global climate change. This project will reconstruct and precisely date the history of marine-based ice in the Ross Sea sector over the last two glacial/interglacial cycles, which will enable a better understanding of the potential driving mechanisms (i.e., sea-level rise, ice dynamics, ocean temperature variations) for ice fluctuations. This will …


Volume Loss From Lower Peyto Glacier, Alberta, Canada, Between 1966 And 2010, Laura M. Kehrl, Robert L. Hawley, Erich C. Osterberg, Dominic A. Winski, Dominic A. Winski, Alexander P. Lee Oct 2014

Volume Loss From Lower Peyto Glacier, Alberta, Canada, Between 1966 And 2010, Laura M. Kehrl, Robert L. Hawley, Erich C. Osterberg, Dominic A. Winski, Dominic A. Winski, Alexander P. Lee

Dartmouth Scholarship

Mass loss from mountain glaciers contributes to sea-level rise and reduces freshwater availability in glacier-fed river basins, with negative effects on hydropower generation, agriculture and the health of aquatic ecosystems. In this study, we determine the volume of lower Peyto Glacier, Alberta, Canada, from ground-penetrating radar surveys in 2008–10, and compare our volume estimate with previous estimates from 1966 and 1984. The long-term record of mass-balance estimates on Peyto Glacier highlights Peyto’s importance as an ‘index’ glacier for the region. We calculate a mean volume of (3.39 0.30) 10m for the glacier snout for the period 2008–10. Glacier volume decreased …


Geogram 2014, David J. Keeling Editor, Wku Department Of Geography And Geology Oct 2014

Geogram 2014, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.


The Impact Of Ice Layers On Gas Transport Through Firn At The North Greenland Eemian Ice Drilling (Neem) Site, Greenland, K. Keegan, M. R. Albert, I. Baker Oct 2014

The Impact Of Ice Layers On Gas Transport Through Firn At The North Greenland Eemian Ice Drilling (Neem) Site, Greenland, K. Keegan, M. R. Albert, I. Baker

Dartmouth Scholarship

Typically, gas transport through firn is modeled in the context of an idealized firn column. However, in natural firn, imperfections are present, which can alter transport dynamics and therefore reduce the accuracy of reconstructed climate records. For example, ice layers have been found in several firn cores collected in the polar regions. Here, we examined the effects of two ice layers found in a NEEM, Greenland firn core on gas transport through the firn. These ice layers were found to have permeability values of 3.0 and 4.0 × 10−10 m2, and are therefore not impermeable layers. However, …


Hyperspectral Measurements Of Wet, Dry And Saline Soils From The Mcmurdo Dry Valleys: Soil Moisture Properties From Remote Sensing, Joseph S. Levy, Anne Nolin, Andrew G. Fountain, James W. Head Oct 2014

Hyperspectral Measurements Of Wet, Dry And Saline Soils From The Mcmurdo Dry Valleys: Soil Moisture Properties From Remote Sensing, Joseph S. Levy, Anne Nolin, Andrew G. Fountain, James W. Head

Geology Faculty Publications and Presentations

Soil moisture is a spatially heterogeneous quantity in the McMurdo Dry Valleys of Antarctica that exerts a large influence on the biological community and on the thermal state of Dry Valleys permafrost. The goal of this project was to determine whether hyperspectral remote sensing techniques could be used to determine soil moisture conditions in the Dry Valleys. We measured the spectral reflectance factors of wetted soil samples from the Dry Valleys under natural light conditions and related diagnostic spectral features to surface layer soil moisture content. Diagnostic water absorption features in the spectra at 1.4 mu m and 1.9 mu …


Optimized Method For Black Carbon Analysis In Ice And Snow Using The Single Particle Soot Photometer, I. A. Wendl, James A. Menking, R. Färber, M. Gysel, Susan D. Kaspari, M. J. G. Laborde, M. Schwikowski Aug 2014

Optimized Method For Black Carbon Analysis In Ice And Snow Using The Single Particle Soot Photometer, I. A. Wendl, James A. Menking, R. Färber, M. Gysel, Susan D. Kaspari, M. J. G. Laborde, M. Schwikowski

All Faculty Scholarship for the College of the Sciences

In this study we attempt to optimize the method for measuring black carbon (BC) in snow and ice using a Single Particle Soot Photometer (SP2). Beside the previously applied ultrasonic (CETAC) and Collison-type nebulizers we introduce a jet (Apex Q) nebulizer to aerosolize the aqueous sample for SP2 analysis. Both CETAC and Apex Q require small sample volumes (a few milliliters) which makes them suitable for ice core analysis. The Apex Q shows the least size-dependent nebulizing efficiency in the BC particle diameter range of 100–1000 nm. The CETAC has the advantage that air and liquid flows can be monitored …


Seasonal And Elevational Variations Of Black Carbon And Dust In Snow And Ice In The Solu-Khumbu, Nepal And Estimated Radiative Forcings, Susan Kaspari, T. H. Painter, M. Gysel, S. M. Skiles, M. Schwikowski Aug 2014

Seasonal And Elevational Variations Of Black Carbon And Dust In Snow And Ice In The Solu-Khumbu, Nepal And Estimated Radiative Forcings, Susan Kaspari, T. H. Painter, M. Gysel, S. M. Skiles, M. Schwikowski

All Faculty Scholarship for the College of the Sciences

Black carbon (BC) and dust deposited on snow and glacier surfaces can reduce the surface albedo, accelerate snow and ice melt, and trigger albedo feedback. Assessing BC and dust concentrations in snow and ice in the Himalaya is of interest because this region borders large BC and dust sources, and seasonal snow and glacier ice in this region are an important source of water resources. Snow and ice samples were collected from crevasse profiles and snow pits at elevations between 5400 and 6400 m a.s.l. from Mera glacier located in the Solu-Khumbu region of Nepal during spring and fall 2009, …


The Monica (Monitoring Of Ice Within Caves) Project: A Multidisciplinary Approach For The Geophysical And Paleoclimatic Characterization Of Permanent Ice Deposits In The Southeastern Alps, Renato R. Colucci, Emanuele Forte, Barbara Stenni, Marco Basso Bondini, Mauro Colle Fontana, Costanza Del Gobbo, Daniele Fontana, Doriana Belligoi, Valter Maggi, Marco Filipazzi Aug 2014

The Monica (Monitoring Of Ice Within Caves) Project: A Multidisciplinary Approach For The Geophysical And Paleoclimatic Characterization Of Permanent Ice Deposits In The Southeastern Alps, Renato R. Colucci, Emanuele Forte, Barbara Stenni, Marco Basso Bondini, Mauro Colle Fontana, Costanza Del Gobbo, Daniele Fontana, Doriana Belligoi, Valter Maggi, Marco Filipazzi

The International Workshop on Ice Caves

On days 30 September and 1-2 October 2013, a 7.8 m long ice core has been extracted from a permanent ice cave deposit in the Southeastern Alps (Vasto’s cave, Mt.Canin - Julian Alps). Each 20 to 100 cm long section of the ice core have been immediately stored in plastic bags and preserved thanks to dry ice. The ice samples, thanks to the helicopter, has been subsequently brought on valley and promptly stored in a refrigerated van, made available by BoFrost. Thus the ice cores has been transported intact to the EUROCOLD laboratory in Milan. These operations have been carried …


The Influence Of Karst Topography To Ice Cave Occurrence - Example Of Ledena Jama In Lomska Duliba (Croatia), Nenad Buzjak Aug 2014

The Influence Of Karst Topography To Ice Cave Occurrence - Example Of Ledena Jama In Lomska Duliba (Croatia), Nenad Buzjak

The International Workshop on Ice Caves

The research of cave microclimate in general contributes to a better understanding of physical and chemical processes in complex karst geoecosystems. Special challenges for researchers are ice caves. This preliminary report is a part of the project dedicated to the research of deep caves on Velebit Mt. and pointed to the influence of the large karst depression microclimate to cave microclimate, e.g. ice and snow accumulation. The one year study using T/RH data loggers was conducted in Lomska duliba valley (Velebit Mt.) known for frequent temperature inversion and low air temperature, and in partially ice-snow filled Ledena jama (Ice shaft) …


New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic Aug 2014

New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic

The International Workshop on Ice Caves

No abstract provided.


Time, Money, And Melting Ice: Proposal For A Coopertive Study Of The World’S Cave Ice In A Race Against Climate Change, George Veni, Lewis Land, Aurel Perşoiu Aug 2014

Time, Money, And Melting Ice: Proposal For A Coopertive Study Of The World’S Cave Ice In A Race Against Climate Change, George Veni, Lewis Land, Aurel Perşoiu

The International Workshop on Ice Caves

Climate change is a global phenomenon that is melting and threatening to melt ice deposits in many of the world’s ice caves. The National Cave and Karst Research Institute of the USA is concerned that major and important paleoclimate and paleoenvironmental records stored in cave ice will soon be lost, and is proposing an international collaborative effort to overcome funding and logistical challenges to sample and analyze at least a representative collection of ice from several regions before further melting occurs.


Using Strat Columns To Interpret Sequence Stragraphy Of Glacial Driven Stream Deposits Of The Acient San Joaquin River, Kyle R. Scharton Aug 2014

Using Strat Columns To Interpret Sequence Stragraphy Of Glacial Driven Stream Deposits Of The Acient San Joaquin River, Kyle R. Scharton

STAR Program Research Presentations

The sedimentary deposits of the ancient San Joaquin River tell the story of river flow through three glacial periods. A strat column shows vertical changes in deposition throughout an outcrop. It can be used to extrapolate the energy level of the flow, and other features of the river at different depositional environments. By looking at trends through the column it is possible to determine how the river’s flow changed through time. Variances in the gravel size and whether it supports itself or is held together by the surrounding sand matrix give clues as to the rate of flow and how …


Hudson Museum Collection: Byrd's Second Antarctic Expedition, 1933-1935, John L. Herrman, Harold Borns Aug 2014

Hudson Museum Collection: Byrd's Second Antarctic Expedition, 1933-1935, John L. Herrman, Harold Borns

UMaine Video

Dr. Harold Borns, Professor Emeritus at the University of Maine Climate Change Institute, narrates original footage of Richard E. Byrd's second Antarctic expedition, 1933-1935. The footage was filmed by John L. Herrmann of Paramount Pictures. The original footage presented was transferred from 16mm film in January 2002 by Northeast Historic Film in Bucksport, Maine, and narration by Dr. Harold Borns added in August 2014. The original film footage is held by the Hudson Museum, University of Maine.


Some New Potential Subterranean Glaciation Research Sites From Velebit Mt. (Croatia), Neven Bočić, Nenad Buzjak, Zoltan Kern Aug 2014

Some New Potential Subterranean Glaciation Research Sites From Velebit Mt. (Croatia), Neven Bočić, Nenad Buzjak, Zoltan Kern

The International Workshop on Ice Caves

Despite the frequent reports about their shrinkage detailed survey of the major subterranean ice deposits is still lacking in Croatia. Here we present cave maps and detailed description of cave ice accumulation from five caves of the Velebit Mt. Morphological constraints allowed ice volume estimation for four of them. Ice volumes were estimated as ~1500 m3 at the Gavranova Pit in 1999, 100 m3 at Štirovača ice cave in 1987, 150 m3 at Japagina 3 in 2000, 1500 m3 at Kugina ice cave in 2004. These new records provide reference data for future studies to evaluate …


Internal Drainage Of Glaciers And Its Origin, Bulat R. Mavlyudov Aug 2014

Internal Drainage Of Glaciers And Its Origin, Bulat R. Mavlyudov

The International Workshop on Ice Caves

Ways of occurrence of elements of an internal drainage of glaciers and also origin of internal drainage systems as a whole are considered. It is shown that elements of an internal drainage can be formed either on the base of fissures and crevasses or by incision of water streams into ice from glacier surface. The basic way of glacier drainage is formed on the base of sliding plane which is formed closely to glacier bed and smooth all roughnesses of the bed. Spreading of water on the surface of this plane during spring time forms not effective drainage system however …


The Sandy Glacier Cave Project: The Study Of Glacial Recession From Within, Eduardo L. Cartaya Aug 2014

The Sandy Glacier Cave Project: The Study Of Glacial Recession From Within, Eduardo L. Cartaya

The International Workshop on Ice Caves

The Sandy Glacier Cave Project is a National Speleological Society (NSS) sponsored study on the unique system of glacier caves located on the Sandy Glacier on the western flank of Mt Hood, Oregon. While the study primarily targets the structure, layout and ice volume change of the ever moving cave system by conducting annual grade 5 surveys, numerous tangential observations and trends have been recorded that are of great interest to the study of glacial recession, watershed hydrology, micro-biology and astro-biology, as well as the study of organic specimens and remains being thawed out of the ice mass by the …


Study Of Multiyear Ice In Medeo Cave (North Ural), Yuri Ivanovich Stepanov, Alexandr Alexandrovich Tainitskiy, Alexandr Valerievich Kichigin, Olga Ivanovna Kadebskaya, Bulat Rafaelevich Mavlyudov Aug 2014

Study Of Multiyear Ice In Medeo Cave (North Ural), Yuri Ivanovich Stepanov, Alexandr Alexandrovich Tainitskiy, Alexandr Valerievich Kichigin, Olga Ivanovna Kadebskaya, Bulat Rafaelevich Mavlyudov

The International Workshop on Ice Caves

The uniqueness of cave ice study lies in characteristic and simulation of continental climate and predictability of its changes. In this study carried out GPR studies in a remote cave Medeo. The cave is located in the territory of Srednevisherski area of West Ural folded zone carbon-bearing karst. The aim of the study was to examine the power and homogeneity of perennial ice formations. According to the results for the first time was defined the power of multi-year ice and built a three-dimensional model of sediment. The cave ice is more enriched with mineral ingredient in comparison with aboveground ice …


Characterization Of Two Permanent Ice Cave Deposits In The Southeastern Alps (Italy) By Means Of Ground Penetrating Radar (Gpr), Renato R. Colucci, Daniele Fontana, Emanuele Forte Aug 2014

Characterization Of Two Permanent Ice Cave Deposits In The Southeastern Alps (Italy) By Means Of Ground Penetrating Radar (Gpr), Renato R. Colucci, Daniele Fontana, Emanuele Forte

The International Workshop on Ice Caves

In order to assess the thickness and the inner structure of some permanent ice deposits in two high elevated alpine karstic caves of the Canin massif (Alpi Giulie, Italy), we performed several multi frequency Ground Penetrating Radar (GPR) surveys. The surveys have been conducted within the project MONICA (MOnitoring of Ice within Caves), aimed at the paleoclimatic characterization of the considered cave ice deposits. GPR surveys have proved to be crucial also in finding the most suitable place for carrying out a drilling core. This has been particularly useful in the Vasto’s ice cave (VIC) in which the direct/visual estimation …


Open Access Data In Polar And Cryospheric Remote Sensing, Allen Pope, W. Rees, Adrian Fox, Andrew Fleming Jul 2014

Open Access Data In Polar And Cryospheric Remote Sensing, Allen Pope, W. Rees, Adrian Fox, Andrew Fleming

Dartmouth Scholarship

This paper aims to introduce the main types and sources of remotely sensed data that are freely available and have cryospheric applications. We describe aerial and satellite photography, satellite-borne visible, near-infrared and thermal infrared sensors, synthetic aperture radar, passive microwave imagers and active microwave scatterometers. We consider the availability and practical utility of archival data, dating back in some cases to the 1920s for aerial photography and the 1960s for satellite imagery, the data that are being collected today and the prospects for future data collection; in all cases, with a focus on data that are openly accessible. Derived data …


Collaborative Research: St. Elias Erosion And Tectonics Project (Steep), Peter O. Koons, Phaedra Upton Jun 2014

Collaborative Research: St. Elias Erosion And Tectonics Project (Steep), Peter O. Koons, Phaedra Upton

University of Maine Office of Research Administration: Grant Reports

1) Refinement of a regional scale model to include an approximation of the true 3D geometry of the orogen.

2) Develop a new local-scale model that incorporates topography, GPS data, and glacial erosion processes to refine the initial results.

3) Develop a modeling experiment to test the hypothesis that the rise and fall of ice masses during glacial cycles might influence where deformation is focused at any given time.


Climate Change And Forest Fires Synergistically Drive Widespread Melt Events Of The Greenland Ice Sheet, Kaitlin M. Keegan, Mary R. Albert, Joseph R. Mcconnell, Ian Baker Jun 2014

Climate Change And Forest Fires Synergistically Drive Widespread Melt Events Of The Greenland Ice Sheet, Kaitlin M. Keegan, Mary R. Albert, Joseph R. Mcconnell, Ian Baker

Dartmouth Scholarship

In July 2012, over 97% of the Greenland Ice Sheet experienced surface melt, the first widespread melt during the era of satellite remote sensing. Analysis of six Greenland shallow firn cores from the dry snow region confirms that the most recent prior widespread melt occurred in 1889. A firn core from the center of the ice sheet demonstrated that exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires reduced albedo below a critical threshold in the dry snow region, and caused the melting events in both 1889 and 2012. We use these data to project the …


Stratigraphic Framework And Landsystem Correlation For Deposits Of The Saginaw Lobe, Michigan, Usa, Ivan R. Guzman Jun 2014

Stratigraphic Framework And Landsystem Correlation For Deposits Of The Saginaw Lobe, Michigan, Usa, Ivan R. Guzman

Masters Theses

Since the time of the Last Glacial Maximum (LGM) the south-central portion of the Lower Michigan Peninsula has been subject to several glacial advances and retreats by the Saginaw lobe. As part of the U.S Geological Survey Great Lakes Geological Mapping Coalition projects, several rotosonic borings were drilled between 2006 and 2013 in Barry, Kalamazoo and Calhoun Counties. Gamma ray logs and textural analyses were completed for each core. Five of these borings were selected according to their diamicton (till) content and correlated using water well logs and surficial geology maps. Glacial deposits such as diamicton serve as evidence of …


Colle Gnifetti Ice Core (Kcc) Progress Report (Year One)—Arcadia Ice Core Proposal: Initiatives On The Science Of The Human Past, Paul Mayewski May 2014

Colle Gnifetti Ice Core (Kcc) Progress Report (Year One)—Arcadia Ice Core Proposal: Initiatives On The Science Of The Human Past, Paul Mayewski

University of Maine Office of Research Administration: Grant Reports

The Colle Gnifetti glacier of the Monta Rosa Massif on the Swiss-Italian border is perfectly situated to offer insight into the intersection of environment (climate) and culture (history of the economy, political stability, pollution, disease) in medieval Europe. While ice cores previously collected at Colle Gnifetti were sampled at state-of-the-art resolution for the time, it was nevertheless impossible to differentiate annual or finer layering in the period older than 1500 A.D. The 2013 Colle Gnifetti expedition thus sought to collect a new ice core that could be analyzed using the ultra-high-resolution laser based technology developed in the Climate Change Institute’s …


Geochemical And Stratigraphic Analysis Of The Linnévatnet Sediment Record: A Study Of Late Holocene Cirque Glacier Activity In Spitsbergen, Svalbard, Graham Harper Edwards May 2014

Geochemical And Stratigraphic Analysis Of The Linnévatnet Sediment Record: A Study Of Late Holocene Cirque Glacier Activity In Spitsbergen, Svalbard, Graham Harper Edwards

Honors Projects

Morainal and lacustrine sediments in Linnédalen, Spitsbergen, Svalbard, record the fluctuations of a glacier in a currently unglaciated mountain cirque during the Little Ice Age (LIA). This study attempts to reconstruct Late Holocene glacial activity within this cirque from geochemical, physical, and visual stratigraphic variation of the Linnévatnet lacustrine sediment record. A 57 cm lacustrine sediment core (D10.5) from Linnévatnet was analyzed at a high-resolution for variations in X-Ray Fluorescence (XRF)-measured elemental composition, spectral reflectance, and magnetic susceptibility. The visual stratigraphy was observed at a microscopic scale. An age-depth model for D10.5 is developed by extrapolating sedimentation rates from dated …


Sustained High Basal Motion Of The Greenland Ice Sheet Revealed By Borehole Deformation, Claudia Ryser, Martin P. Lüthi, Lauren C. Andrews, Matthew J. Hoffman, Ginny A. Catania, Robert L. Hawley Apr 2014

Sustained High Basal Motion Of The Greenland Ice Sheet Revealed By Borehole Deformation, Claudia Ryser, Martin P. Lüthi, Lauren C. Andrews, Matthew J. Hoffman, Ginny A. Catania, Robert L. Hawley

Dartmouth Scholarship

Ice deformation and basal motion characterize the dynamical behavior of the Greenland ice sheet (GrIS). We evaluate the contribution of basal motion from ice deformation measurements in boreholes drilled to the bed at two sites in the western marginal zone of the GrIS. We find a sustained high amount of basal motion contribution to surface velocity of 44–73% in winter, and up to 90% in summer. Measured ice deformation rates show an unexpected variation with depth that can be explained with the help of an ice-flow model as a consequence of stress transfer from slippery to sticky areas. This effect …


Near-Surface Internal Melting: A Substantial Mass Loss On Antarctic Dry Valley Glaciers, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston Apr 2014

Near-Surface Internal Melting: A Substantial Mass Loss On Antarctic Dry Valley Glaciers, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys, southern Victoria Land, East Antarctica, are a polar desert, and melt from glacial ice is the primary source of water to streams, lakes and associated ecosystems. Previous work found that to adequately model glacier ablation and subsurface ice temperatures with a surface energy-balance model required including the transmission of solar radiation into the ice. Here we investigate the contribution of subsurface melt to the mass balance of (and runoff from) Dry Valley glaciers by including a drainage process in the model and applying the model to three glacier sites using 13years of hourly meteorological data. Model …