Researchers Pool Knowledge About Antarctic Dry Valleys, 2015 Portland State University
Researchers Pool Knowledge About Antarctic Dry Valleys, Andrew G. Fountain, Sarah Spaulding
Andrew G. Fountain
Most of us think of ice when we think of the Antarctic, and rightly so, considering that only 5% of it is ice-free. Dry valleys--the ice-free areas--have sandy, rocky valley floors, ice-covered lakes, and streams that flow only two months of the year. The McMurdo Dry Valleys (78øS 163øE) are the largest of these regions.
Hydrologic Response To Extreme Warm And Cold Summers In The Mcmurdo Dry Valleys, East Antarctica, 2015 University of Illinois at Chicago
Hydrologic Response To Extreme Warm And Cold Summers In The Mcmurdo Dry Valleys, East Antarctica, Peter T. Doran, Christopher P. Mckay, Andrew G. Fountain, Thomas H. Nylen, Diane M. Mcknight, Chris Jaros, John E. Barrett
Andrew G. Fountain
The meteorological characteristics and hydrological response of an extreme warm, and cold summer in the McMurdo Dry Valleys are compared. The driver behind the warmer summer conditions was the occurrence of down-valley winds, which were not present during the colder summer. Occurrence of the summer down-valley winds coincided with lower than typical mean sea level pressure in the Ross Sea region. There was no significant difference in the amount of solar radiation received during the two summers. Compared to the cold summer, glaciological and hydrological response to the warm summer in Taylor Valley included significant glacier mass loss, and 3- ...
A Stable Isotopic Investigation Of A Polar Desert Hydrologic System, Mcmurdo Dry Valleys, Antarctica, 2015 Colorado School of Mines
A Stable Isotopic Investigation Of A Polar Desert Hydrologic System, Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, W. Berry Lyons, Diane M. Mcknight, Bruce H. Vaughn, Andrew G. Fountain, Carolyn Dowling
Andrew G. Fountain
The hydrologic system of the coastal McMurdo Dry Valleys, Antarctica, is defined by snow accumulation, glacier melt, stream flow, and retention in closed-basin, ice-covered lakes. During the austral summers from 1993-1996 and 1999-2000 to 2002-2003, fresh snow, snow pits, glacier ice, stream water, and lake waters were sampled for the stable isotopes deuterium (D) and 18O in order to resolve sources of meltwater and the interactions among the various hydrologic reservoirs in the dry valleys. This data set provides a survey of the distribution of natural water isotope abundances within the well-defined dry valley hydrologic system in Taylor Valley, which ...
Glacier Change On The Three Sisters Volcanoes, Oregon: 1900-2010, 2015 Portland State University
Glacier Change On The Three Sisters Volcanoes, Oregon: 1900-2010, Justin George Ohlschlager
Dissertations and Theses
A glacier responds to changes in climate by subsequent retreat and advance as a result of changes in snow inputs and outputs. Understanding these changes is important because shrinking glaciers limit and diminish local water resources. They contribute to alpine runoff in the late-summer months by delaying the maximum runoff until late in the melt season. A comprehensive glacier and perennial snowfield inventory has not been completed for the Three Sisters in Central Oregon. Using aerial photography, Digital Elevation Models (DEMs), previous studies, and historical ground based photographs these glacier and perennial snowfields were defined and their surface area change ...
Temperature Distribution And Thermal Anomalies Along A Flowline Of The Greenland Ice Sheet, 2015 University of Wyoming
Temperature Distribution And Thermal Anomalies Along A Flowline Of The Greenland Ice Sheet, Joel A. Harrington, Neil F. Humphrey, Joel T. Harper
Geosciences Faculty Publications
Englacial and basal temperature data for the Greenland ice sheet (GrIS) are sparse and mostly limited to deep interior sites and ice streams, providing an incomplete representation of the thermal state of ice within the ablation zone. Here we present 11 temperature profiles at five sites along a 34km east-west transect of West Greenland. These profiles depict ice temperatures along a flowline and local temperature variations between closely spaced boreholes. A temperate basal layer is present in all profiles, increasing in thickness in the flow direction, where it expands from about 3% of ice height furthest inland to 100% at ...
Evidence Of Late Quaternary Fires From Charcoal And Siliceous Aggregates In Lake Sediments In The Eastern U.S.A., 2015 University of Tennessee - Knoxville
Evidence Of Late Quaternary Fires From Charcoal And Siliceous Aggregates In Lake Sediments In The Eastern U.S.A., Joanne P. Ballard
The late-glacial transition to the Holocene, 15,000–11,600 cal yr BP, is an enigmatic period of dynamic global changes and a major extinction event in North America. Fire is an agent of disturbance that transforms the environment physically and chemically, and affects plant community composition. To improve understanding of the linkages between fire, vegetation, and climate over the late glacial and Holocene in the eastern U.S., I analyzed lake-sediment cores for charcoal and indicators of wood ash, and compared results to existing pollen records. A new microscopic charcoal record from Anderson Pond, Tennessee revealed high fire activity ...
Establishing A Chronology Of Late Quaternary Glacial Advances In The Cordillera De Talamanca, Costa Rica, 2015 University of Tennessee - Knoxville
Establishing A Chronology Of Late Quaternary Glacial Advances In The Cordillera De Talamanca, Costa Rica, Rebecca Susan Potter
Little research has focused on glacial events in the tropics. Providing an absolute glacial chronology in Costa Rica will build a foundation for future glacial chronologies and paleoclimate reconstructions in the highlands of Central America. Evidence of past glaciation, including moraines and glacial lakes, is preserved within formerly glaciated valleys in the Cordillera de Talamanca. Orvis and Horn (2000) constrained deglaciation ages of the most recent glacial event in the Cordillera de Talamanca based on radiocarbon dates of glacial lake sediments. Radiocarbon ages indicated complete deglaciation after 12.4 ka cal BP but before 9.7 ka cal BP (Orvis ...
Timing And Extent Of The Little Ice Age Glacial Advances In The Eastern Tian Shan, China, 2015 University of Tennessee - Knoxville
Timing And Extent Of The Little Ice Age Glacial Advances In The Eastern Tian Shan, China, Yanan Li
Located in Central Asia, one of the most continental regions on Earth, the Tian Shan’s glaciers contribute critical fresh water to populated areas in the lowland. These glaciers are sensitive to climate change, and knowledge of contemporary glaciers and their changes in the past is of critical importance for sustainable development in this region. Constraining glacial fluctuations in recent centuries will fill a gap in numerical constraints on glacial history and paleoclimate information, and provide important evidence on the spatio-temporal changes of the climate systems in the Tian Shan. This doctoral dissertation investigates the timing and extent of Little ...
Dye Tracing To Determine Flow Properties Of Hydrocarbon-Polluted Rabots Glaciär, Kebnekaise, Sweden, 2015 Stockholm University
Dye Tracing To Determine Flow Properties Of Hydrocarbon-Polluted Rabots Glaciär, Kebnekaise, Sweden, Caroline C. Clason, C. Coch, J. Jarsjö, Keith A. Brugger, P. Jansson, G. Rosqvist
Over 11 000 L of kerosene was deposited on the surface of Rabots glaciär on the Kebnekaise Massif, northern Sweden, following the crash of a Royal Norwegian Air Force aircraft in March 2012. An environmental monitoring programme was subsequently commissioned, including a series of dye tracing experiments during the 2013 melt season, conducted to investigate the transport of pollutants through the glacier hydrological system. This experimental set-up provided a basis from which we could gain new insight into the internal hydrological system of Rabots glaciär. Results of dye tracing experiments reveal a degree of homogeneity in the topology of the ...
Roosevelt Island Climate Evolution Project (Rice): Us Deep Ice Core Glaciochemistry Contribution (2011- 2014), 2015 Principal Investigator; University of Maine, Orono
Roosevelt Island Climate Evolution Project (Rice): Us Deep Ice Core Glaciochemistry Contribution (2011- 2014), Paul Andrew Mayewski, Karl J. Kreutz, Andrei V. Kurbatov
University of Maine Office of Research and Sponsored Programs: Grant Reports
This award supports a project to analyze a deep ice core which will be drilled by a New Zealand research team at Roosevelt Island. The objectives are to process the ice core at very high resolution to (a) better understand phasing sequences in Arctic/Antarctic abrupt climate change, even at the level of individual storm events; (b) determine the impact of changes in the Westerlies and the Amundsen Sea Low on past/present/future climate change; (c) determine how sea ice extent has varied in the area; (d) compare the response of West Antarctica climate to other regions during glacial ...
Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, 2015 Far Eastern Federal University
Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, Alexander T. Bekker, Nikita Ya. Tsimbelman, Tatiana I. Chernova, Vadim D. Bruss, Ömer Bilgin
Civil and Environmental Engineering and Engineering Mechanics Faculty Publications
Thin metal or reinforced concrete shells with granular infill structures are considered in this article. These structures are massive and they are used as support for the construction of berthing quays, piers, artificial islands, shore protection, and other structures of coastal infrastructure. It is more convenient to use the thin shell structures during the development of the Arctic shelf, because it is possible to install them from the ice side. In addition, it is possible to enhance the technology and install thin shells with infill on deeper solid foundation layers. A mathematical model for the stresses on a compressible foundation ...
Experimental Recreation Of The Sub-Glacial System, An Analysis Of Hold Time Versus Strengthening To Shed Light On The Mechanics Of Stick-Slip Ice Streams, Ian Mcbrearty
Symposium on Undergraduate Research and Creative Expression
Ice streams in Antarctica are known to move ice rapidly, in a narrow band, over a loose permeable substrate to the sea- contributing to sea-level rise and the decay of the Antarctic Ice Sheet. It has been observed that some of these ice streams move in a “stick-slip” fashion, lurching ahead small steps at a time. Past workers have proposed this observation is indicative of temporal strengthening in the ice stream when it’s sitting at rest, but have not satisfactorily concluded which components of the glacial system are directly causing the strengthening. To understand the mechanics dictating ice stream ...
Determining Provenance Of Glacial Material In Southwestern Ohio, 2015 Cedarville University
Determining Provenance Of Glacial Material In Southwestern Ohio, Jorian Krob
The Research and Scholarship Symposium
During the last glacial maximum, ice moved south from Canada to cover much of the northern United States. This included the northern and western portions of Ohio. As the ice migrated it picked up Canadian bedrock which it transported and then left in Ohio when the ice retreated. The goal of this project was to determine the provenance (the source of origin) of the glacial material that is located in Greene, Clark, Montgomery, Logan, and Champaign Counties in Ohio. To determine where in southern Canada the material in these counties came from, this project included literature review into the glacial ...
Glacial Till Prospecting In Southwest Ohio: Implications For Improved Sampling, 2015 Cedarville University
Glacial Till Prospecting In Southwest Ohio: Implications For Improved Sampling, Dylan J. Mckevitt
The Research and Scholarship Symposium
Glacial till (drift) prospecting has served a major role in corporate mineral exploration, especially for gold and diamond during the past 30 years. It involves analyzing heavy indicator minerals from bulk sampling of various glacial deposits in order to track up ice flow direction to the potential orebody (such as a kimberlite pipe or Cu-Ni deposit), a technique commonly used in Canada but not in the U.S. Heavy minerals including diamond, gold, and native copper have been found in Ohio glacial till; the provenance of these heavy minerals is the Precambrian bedrock north of Ohio. This study utilized standard ...
Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments, 2015 University College London
Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments, Francesco Iacoviello, Giovanna Giorgetti, Isabella Turbanti Memmi, Sandra Passchier
ANDRILL Research and Publications
The present study deals with heavy mineral analysis of late Early Miocene marine sediments recovered in the McMurdo Sound region (Ross Sea, Antarctica) during the ANDRILL— SMS Project in 2007. The main objective is to investigate how heavy mineral assemblages reflect different source rocks and hence different provenance areas. These data contribute to a better understanding of East Antarctica ice dynamics in the Ross Sea sector during the Early Miocene (17.6–20.2 Ma), a time of long-term global warming and sea level rise. The AND-2A drill core recovered several stratigraphic intervals that span from Early Miocene to Pleistocene ...
Glacier Slip And Seismicity Induced By Surface Melt, 2015 Iowa State University
Glacier Slip And Seismicity Induced By Surface Melt, Peter Lindsay Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Mark E. Mathison, Denis Cohen
Peter Lindsay Moore
Many of the key processes governing fast glacier flow involve interaction between a glacier and its basal hydrological system, which is hidden from direct observation. Passive seismic monitoring has shown promise as a tool for remotely monitoring basal processes, but lack of glacier-bed access prevents clear understanding of the relationships between subglacial processes and corresponding seismic emissions. Here we describe direct measurements of basal hydrology, sliding, and broadband seismicity made in a unique subglacial facility in Norway during the onset of two summer melt seasons. In the most pronounced of these episodes, rapid delivery of surface meltwater to the bed ...
Ice Flow Across A Warm-Based/Cold-Based Transition At A Glacier Margin, 2015 Iowa State University
Ice Flow Across A Warm-Based/Cold-Based Transition At A Glacier Margin, Peter Lindsay Moore, Neal R. Iverson, Denis Cohen
Peter Lindsay Moore
Where polythermal glaciers have frozen margins that buttress otherwise temperate-based sliding ice, longitudinal compression can strongly influence ice flow trajectory, and consequently sediment transport paths. Past efforts to model flow in the vicinity of a basal thermal transition (BTT) have generally relied on simplified boundary conditions or rheological idealizations, making these model results difficult to apply to real glacier termini. Herein, we present results of numerical simulations using a power-law rheology and with boundary conditions that better represent the frozen margin. Model results indicate that a transition to a non-sliding frozen margin causes a decline in surface velocity made possible ...
Effect Of A Cold Margin On Ice Flow At The Terminus Of Storglacïaren, Sweden: Implications For Sediment Transport, Peter Lindsay Moore, Neal R. Iverson, Keith A. Brugger, Denis Cohen, Thomas S. Hooyer, Peter Jansson
Peter Lindsay Moore
The cold-based termini of polythermal glaciers are usually assumed to adhere strongly to an immobile substrate and thereby supply significant resistance to the flow of warm-based ice upglacier. This compressive environment is commonly thought to uplift basal sediment to the surface of the glacier by folding and thrust faulting. We present model and field evidence from the terminus of Storglacïaren, Sweden, showing that the cold margin provides limited resistance to flow from up-glacier. Ice temperatures indicate that basal freezing occurs in this zone at 10–1 – 10–2 ma–1, but model results indicate that basal motion at rates greater ...
Debris-Bed Friction Of Hard-Bedded Glaciers, 2015 Iowa State University
Debris-Bed Friction Of Hard-Bedded Glaciers, Denis Cohen, Neal R. Iverson, T. S. Hooyer, U. H. Fischer, M. Jackson, Peter Lindsay Moore
Peter Lindsay Moore
Field measurements of debris-bed friction on a smooth rock tablet at the bed of Engabreen, a hard-bedded, temperate glacier in northern Norway, indicated that basal ice containing 10% debris by volume exerted local shear traction of up to 500 kPa. The corresponding bulk friction coefficient between the dirty basal ice and the tablet was between 0.05 and 0.08. A model of friction in which nonrotating spherical rock particles are held in frictional contact with the bed by bed-normal ice flow can account for these measurements if the power law exponent for ice flowing past large clasts is 1 ...
Deformation Of Debris-Ice Mixtures, 2015 Iowa State University
Deformation Of Debris-Ice Mixtures, Peter Lindsay Moore
Peter Lindsay Moore
Mixtures of rock debris and ice are common in high-latitude and high-altitude environments and are thought to be widespread elsewhere in our solar system. In the form of permafrost soils, glaciers, and rock glaciers, these debris-ice mixtures are often not static but slide and creep, generating many of the landforms and landscapes associated with the cryosphere. In this review, a broad range of field observations, theory, and experimental work relevant to the mechanical interactions between ice and rock debris are evaluated, with emphasis on the temperature and stress regimes common in terrestrial surface and near-surface environments. The first-order variables governing ...