Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, 2018 Louisiana State University and Agricultural and Mechanical College
Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, Louis Stephen Garcia
LSU Master's Theses
Glacial outburst floods are difficult to predict and threaten human life. These events are characterized by rapid draining of glacier-dammed lakes via the sub/englacial hydraulic network to the proglacial stream. The glacier-dammed lake on Gornergletscher in Switzerland, which fills and drains each summer, provides an opportunity to study this hazard. For three drainages (2004, 2006, and 2007), icequakes (IQ) are tracked as well as on-ice GPS movement. The seasonal seismic networks had 8 – 24 three-component stations and apertures of about 300 – 400 m on the glacier surface. The seasonal GPS arrays contained 4 – 8 GPS antennae on the glacier ...
Multi-Channel Ground-Penetrating Radar For The Continuous Quantification Of Snow And Firn Density, Depth, And Accumulation, Tate Meehan
Boise State University Theses and Dissertations
A priority of ice sheet surface mass balance (SMB) prediction is ascertaining the surface density and annual snow accumulation. These forcing data are inputs for firn density models and can be used to inform remotely sensed ice sheet surface processes and to assess Regional Climate Model (RCM) skill. The Greenland Traverse for Accumulation and Climate Studies (GreenTrACS) retrieved 16 shallow firn cores and dug 42 snow pits along the Western percolation zone of the Greenland Ice Sheet (GrIS) during May and June of 2016 and 2017. I deployed and maintained a multi-channel 500 MHz ground-penetrating radar in a multi-offset configuration ...
Carbon Flux And Weathering Processes In Icelandic Glacial-Fed Rivers, 2018 Western Kentucky University
Carbon Flux And Weathering Processes In Icelandic Glacial-Fed Rivers, Allison Quiroga
Masters Theses & Specialist Projects
An investigation into the carbon dynamics and weathering processes occurring in Icelandic glacial-fed streams was conducted during the spring to summer seasonal transition in June of 2017. Four major outlet rives were sampled from the glaciers of Gígjökull, Steinsholtsjökull, Sólheimajökull, and Falljökull. Markarfljót, the major river that Gígjökull, Steinsholtsjökull, and many other glaciers drain into, was also sampled. Longitudinal sampling occurred at all sites to capture downstream trends in the hydrogeochemistry and carbon dynamics. Distinct differences in geochemistry between glacier surface meltwater, sub-glacial waters, pro-glacial lake water, and post-mixed downstream samples were evident in the data. Glacier surface streams were ...
Mapping And Interpreting The Glacial Geology Of Pictured Rocks National Lakeshore, Michigan, 2018 Western Michigan University
Mapping And Interpreting The Glacial Geology Of Pictured Rocks National Lakeshore, Michigan, Sarah M. Vandermeer
Pictured Rocks National Lakeshore is among the most popular parks in Michigan, yet prior to this study, it was the only National Park that lacked a detailed surficial geology map characterizing the distribution of sediments and landforms. Additionally, much of the landscape remained unexplored. These factors prevented thorough interpretations of landscape development and evolution. This research aims to map and further explore the relationship of glacial sediments and landforms throughout Pictured Rocks to refine and expand the current understanding of glacial events that shaped this landscape.
A new, detailed (1:24,000-scale) surficial geology map of the ten 7.5-minute ...
Drivers Of Solar Radiation Variability In The Mcmurdo Dry Valleys, Antarctica, 2018 U.S. Geological Survey
Drivers Of Solar Radiation Variability In The Mcmurdo Dry Valleys, Antarctica, Maciej K. Obryk, Andrew G. Fountain, Peter T. Doran
Geology Faculty Publications and Presentations
Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m−2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry ...
Improved Estimates Of Glacier Change Rates At Nevado Coropuna Ice Cap, Peru, 2018 Dickinson College
Improved Estimates Of Glacier Change Rates At Nevado Coropuna Ice Cap, Peru, William Hardy Kochtitzky, Benjamin R. Edwards, Ellyn M. Enderlin, Jersy Marino, Nelida Marinque
Faculty and Staff Publications By Year
Accurate quantification of rates of glacier mass loss is critical for managing water resources and for assessing hazards at ice-clad volcanoes, especially in arid regions like southern Peru. In these regions, glacier and snow melt are crucial dry season water resources. In order to verify previously reported rates of ice area decline at Nevado Coropuna in Peru, which are anomalously rapid for tropical glaciers, we measured changes in ice cap area using 259 Landsat images acquired from 1980 to 2014. We find that Coropuna Ice Cap is presently the most extensive ice mass in the tropics, with an area of ...
Rapid Expansion Of Greenland’S Low-Permeability Ice Slabs In A Warming Climate, 2018 University of Colorado at Boulder
Rapid Expansion Of Greenland’S Low-Permeability Ice Slabs In A Warming Climate, Michael John Macferrin
Cooperative Institute for Research in Environmental Sciences Graduate Theses & Dissertations
Recent increases in Greenland’s glacial melt have accelerated runoff and become Greenland’s dominant mechanism of ice loss. More meltwater is being generated in the ice sheet’s lower accumulation zone, which has begun to anneal ice lenses found within the porous firn and form continuous low-permeability ice slabs (LPISs). LPISs are layers of ice meters thick that inhibit water percolating beneath them, extend horizontally for tens of kilometers, and can cause runoff from regions where water previously refroze. LPISs form on decadal timescales and have the potential to quickly increase the extent of Greenland’s runoff zone. I ...
Oceanographic And Climatic Change In The Bering Sea, Last Glacial Maximum To Holocene, 2018 University of Northern British Columbia
Oceanographic And Climatic Change In The Bering Sea, Last Glacial Maximum To Holocene, Ben M. Pelto, Beth E. Caissie, Steven T. Petsch, Julie Brigham-Grette
Geological and Atmospheric Sciences Publications
Post‐glacial sea level rise led to a direct connection between the Arctic and Pacific Oceans via the Bering Strait. Consequently, the Bering Sea experienced changes in connectivity, size, and sediment sources that were among the most drastic of any ocean basin in the past 30,000 years. However, the sedimentary response to the interplay between climate change and sea level rise in high‐latitude settings such as Beringia remains poorly resolved. To ascertain changes in sediment delivery, productivity, and regional oceanography from the Last Glacial Maximum (LGM) to the Holocene, we analyzed sedimentological, geochemical, and isotopic characteristics of three ...
Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, 2018 Old Dominion University
Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, Aradhna Tripati, Dennis Darby
OEAS Faculty Publications
Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with ...
The Impact Of Reduced Arctic Sea Ice Extent On Cryospheric Snowfall, 2017 University of Nebraska-Lincoln
The Impact Of Reduced Arctic Sea Ice Extent On Cryospheric Snowfall, Alexander Carne
Dissertations & Theses in Earth and Atmospheric Sciences
Satellite observations show that sea ice extent in the Arctic has been declining from 1979 through present day, reaching record minimum extents in 2007 and 2012. Reduced sea ice extent allows for greater expanses of open water to interact with the Arctic atmosphere, potentially leading to changes in the Arctic climate. The greatest declines in Arctic sea ice extent have occurred in summer and autumn. During these seasons, it is likely that the decrease in Arctic sea ice extent led to an increase in atmospheric sensible and latent heat fluxes, possibly leading to increases in Arctic temperature and moisture. Increases ...
Revealing Our Melting Past: Rescuing Historical Snow And Ice Data, 2017 University of Denver
Revealing Our Melting Past: Rescuing Historical Snow And Ice Data, Jack Maness, Ruth Duerr, Michael Dulock, Florence Fetterer, Gloria Hicks, Athea Merredyth, William Sampson, Allaina Wallace
University Libraries Faculty & Staff Contributions
Analog archival data can supplement modern digital research, but only if those data are preserved, described, and migrated to appropriate formats. The National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder (CU) is responsible for managing, archiving, and disseminating cryospheric and polar data. The clear majority of these data are digital, but the NSIDC also houses a collection of historical archival materials that include measurements related to the earth's glaciated regions prior to the development of modern instrumentation. Their formats, however, are not conducive to contemporary analysis, rendering them ostensibly “lost” to research. This paper ...
Monitoring Tropical Debris-Covered Glacier Dynamics From High-Resolution Unmanned Aerial Vehicle Photogrammetry, Cordillera Blanca, Peru, Oliver Wigmore, Bryan G. Mark
University Libraries Open Access Fund Supported Publications
The glaciers of the Cordillera Blanca, Peru, are rapidly retreating and thinning as a result of climate change, altering the timing, quantity and quality of water available to downstream users. Furthermore, increases in the number and size of proglacial lakes associated with these melting glaciers is increasing potential exposure to glacier lake outburst floods (GLOFs). Understanding how these glaciers are changing and their connection to proglacial lake systems is thus of critical importance. Most satellite data are too coarse for studying small mountain glaciers and are often affected by cloud cover, while traditional airborne photogrammetry and lidar are costly. Recent ...
Raritan Formation (Upper Cretaceous), Long Island, New York: Sedimentological And Geochemical Assessment, Nazrul I. Khandaker, Arif Sikder, Stanley Schleifer, Xin-Chen Liu, Carlos E. Castano Londano, Joseph B. Mcgee Turner
Publications and Research
The lithology of the Upper Cretaceous Raritan Formation (RF) consists of two members: an upper clay member (Raritan clay) and a lower unit, the Lloyd Sand Member. RF is unconformably overlain by upper Pleistocene glacial deposits. The RF consists of stratified white, light- to dark-gray, and red beds and lenses of clay, silt, and sand; lignite and pyrite are common. Variegated, thin to thickly-bedded Lloyd sandstone (LS) is considered to be one of the extensive regional aquifers in Long Island and interpreted to be nearshore, fluvio-deltaic deposit. Proximity to fluvial axes and active deltaic lobes plays an important role in ...
Giovanni Badino (1953-2017), 2017 International Union of speleology
Giovanni Badino (1953-2017), Arrigo Cigna, Paolo Forti
International Journal of Speleology
Short obituary of Giovanni Badino.
Oxygen Isotope Ratios In The Shell Of Mytilus Edulis: Archives Of Glacier Meltwater In Greenland?, 2017 University of Reading
Oxygen Isotope Ratios In The Shell Of Mytilus Edulis: Archives Of Glacier Meltwater In Greenland?, E. A. A. Verteegh, M. E. Blicher, J. Mortensen, S. Rysgaard, T. D. Als, Alan D. Wanamaker
Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute significantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into the past are vital for validating models predicting the influence of ongoing climate change. We investigated a potential meltwater proxy in Godthåbsfjord (West Greenland), where glacier meltwater causes seasonal excursions with lower oxygen isotope water (δ18Ow) values and salinity. The blue mussel (Mytilus edulis) potentially records these variations, because it precipitates its shell calcite in oxygen isotopic equilibrium with ambient ...
Odu Scientists Address Antarctic Ice Melt Affecting Sea Levels, 2017 Old Dominion University
Odu Scientists Address Antarctic Ice Melt Affecting Sea Levels, Miasia Osbey
No abstract provided.
The Geography Of Glaciers And Perennial Snowfields In The American West, 2017 Portland State University
The Geography Of Glaciers And Perennial Snowfields In The American West, Andrew G. Fountain, Bryce Glenn, Hassan J. Basagic
Geology Faculty Publications and Presentations
A comprehensive mid-20th century inventory of glaciers and perennial snowfields (G&PS) was compiled for the American West, west of the 100° meridian. The inventory was derived from U.S. Geological Survey 1:24,000 topographic maps based on aerial photographs acquired during 35 years, 1955–1990, of which the first 20 years or more was a cool period with little glacier change. The mapped features were filtered for those greater than 0.01 km2. Results show that 5036 G&PS (672 km2, 14 km3) populate eight states, of which about 1276 (554 km2, 12 km3) are glaciers. Uncertainty is ...
Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, 2017 University of Texas at Austin
Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler
Fractures that propagate off of weak slip planes are known as wing cracks and often play important roles in both tectonic deformation and fluid flow across reservoir seals. Previous numerical models have produced the basic kinematics of wing crack openings but generally have not been able to capture fracture geometries seen in nature. Here we present both a phase-field modeling approach and a physical experiment using gelatin for a wing crack formation. By treating the fracture surfaces as diffusive zones instead of as discontinuities, the phase-field model does not require consideration of unpredictable rock properties or stress inhomogeneities around crack ...
Soft-Bed Experiments Beneath Engabreen, Norway: Regelation Infiltration, Basal Slip And Bed Deformation, 2017 Iowa State University
Soft-Bed Experiments Beneath Engabreen, Norway: Regelation Infiltration, Basal Slip And Bed Deformation, Neal R. Iverson, Thomas S. Hooyer, Urs H. Fischer, Denis Cohen, Peter L. Moore, M. Jackson, G. Lappegard, J. Kohler
To avoid some of the limitations of studying soft-bed processes through boreholes, a prism of simulated till (1.8 m × 1.6 m × 0.45 m) with extensive instrumentation was constructed in a trough blasted in the rock bed of Engabreen, a temperate glacier in Norway. Tunnels there provide access to the bed beneath 213 m of ice. Pore-water pressure was regulated in the prism by pumping water to it. During experiments lasting 7–12 days, the glacier regelated downward into the prism to depths of 50– 80 mm, accreting ice-infiltrated till at rates predicted by theory. During periods of ...
Testing A Glacial Erosion Rule Using Hang Heights Of Hanging Valleys, Jasper National Park, Alberta, Canada, 2017 University of Alaska, Fairbanks
Testing A Glacial Erosion Rule Using Hang Heights Of Hanging Valleys, Jasper National Park, Alberta, Canada, J. M. Amundson, Neal R. Iverson
In most models of glacial erosion, glacier sliding velocity is hypothesized to control rates of bedrock erosion. If this hypothesis is correct, then the elevation difference between hanging and trunk valley floors, the hang height, should be dictated by the relative sliding velocities of the glaciers that occupied these valleys. By considering sliding velocity to be proportional to balance velocity and using mass continuity, hang height is expressed in terms of glacier catchment areas, slopes, and widths, which can be estimated for past glaciers from the morphology of glacial valleys. These parameters were estimated for 46 hanging valleys and their ...