Late Pleistocene Glaciation In The Mosquito Range, Colorado, U.S.A.: Chronology And Climate,
2019
University of Minnesota, Morris
Late Pleistocene Glaciation In The Mosquito Range, Colorado, U.S.A.: Chronology And Climate, Keith A. Brugger, Benjamin J.C. Laabs, Alexander Reimers, Noah Bensen
Geology Publications
New cosmogenic 10Be surface exposure ages from seventeen moraine boulders in the Mosquito Range suggest that glaciers were at their late Pleistocene (Pinedale) maximum extent at ~21–20 ka, and that ice recession commenced prior to ~17 ka. These age limits suggest that the Pinedale Glaciation was synchronous within the Colorado Rocky Mountain region. Locally, the previous (Bull Lake) glaciation appears to have occurred no later than 117 ka, possibly ~130 ka allowing for reasonable rock weathering rates. Temperature-index modeling is used to determine the magnitude of temperature depression required to maintain steady-state mass balances of seven reconstructed glaciers at …
Snowmelt Detection On Alpine Glaciers Using Synthetic Aperture Radar Time Series,
2019
CUNY City College
Snowmelt Detection On Alpine Glaciers Using Synthetic Aperture Radar Time Series, Corey Scher
Dissertations and Theses
Hindu Kush Himalayan (HKH) glaciers serve as some of the most sensitive indicators of changes in global climate. These glaciers shape the hydrologic dynamics of river systems supplying freshwater to over 2 billion people throughout Asia and regulate the geochemistry of sensitive aquatic alpine ecosystems. As snowmelt onsets sooner, lasts longer, and snowfields retreat due to increases in global temperature, the hydrologic dynamics of catchments draining HKH threaten to change the availability of surface freshwater resources for nearly one fifth of the global population, disturb sensitive aquatic habitat, and precipitate hazards associated with glacier wasting. Informed planning and decision-making around …
Reanalysis Of The Us Geological Survey Benchmark Glaciers: Long-Term Insight Into Climate Forcing Of Glacier Mass Balance,
2019
U.S. Geological Survey Alaska Science Center
Reanalysis Of The Us Geological Survey Benchmark Glaciers: Long-Term Insight Into Climate Forcing Of Glacier Mass Balance, Shad O’Neel, Christopher Mcneil, Louis Sass, Caitlyn Florentine, Emily Baker, Andrew G. Fountain, Multiple Additional Authors
Geology Faculty Publications and Presentations
Mountain glaciers integrate climate processes to provide an unmatched signal of regional climate forcing. However, extracting the climate signal via intercomparison of regional glacier mass-balance records can be problematic when methods for extrapolating and calibrating direct glaciological measurements are mixed or inconsistent. To address this problem, we reanalyzed and compared long-term mass-balance records from the US Geological Survey Benchmark Glaciers. These five glaciers span maritime and continental climate regimes of the western United States and Alaska. Each glacier exhibits cumulative mass loss since the mid-20th century, with average rates ranging from −0.58 to −0.30 m w.e. a−1. We produced a …
Ice Flow Impacts The Firn Structure Of Greenland's Percolation Zone,
2019
University of Montana, Missoula
Ice Flow Impacts The Firn Structure Of Greenland's Percolation Zone, Rosemary C. Leone
Graduate Student Theses, Dissertations, & Professional Papers
One dimensional simulations of firn evolution neglect horizontal transport as the firn column moves down slope during burial. This approach is justifiable near Greenland's ice divide, where ice flow is near vertical, but fidelity is lost in the percolation zone where horizontal ice flow advects the firn column through climate gradients. We simulate firn evolution processes under advection conditions using a transient, thermo-mechanically coupled model for firn densification and heat transfer with various schemes for meltwater penetration and refreezing. The simulations isolate processes in synthetic runs and investigate an ice core site and four transects of Greenland’s percolation zone. The …
Analysis Of A Paleoglacier Reconstruction Model For Valley Glaciers Of The Wind River Range, Wyoming,
2019
University of Northern Iowa
Analysis Of A Paleoglacier Reconstruction Model For Valley Glaciers Of The Wind River Range, Wyoming, Taylor Rae Garton
Dissertations and Theses @ UNI
Various approaches, ranging from in-field morphological reconstructions to more technology-based modelling practices allow us to reconstruct and understand the long-term geomorphic evolution of landscapes. The study of paleo-environments by reconstruction can also give us profound insight into paleo-climate. A new model, GlaRe (Glacial Reconstruction), has been introduced into the alpine glacier modeling community to facilitate glacier reconstruction. In this research the mathematical equations representing the basal shear stress parameter are tested to determine the applicability of the GlaRe model to alpine glaciers in the American West. Known ages and extents of past glacier advances were used to test the reconstructions …
Climate Evolution Across The Mid-Brunhes Transition,
2018
Rowan University
Climate Evolution Across The Mid-Brunhes Transition, Aaron M. Barth, Peter U. Clark, Nicholas S. Bill, Feng He, Nicklas G. Pisias
School of Earth & Environment Departmental Research
The Mid-Brunhes Transition (MBT) began ∼ 430 ka with an increase in the amplitude of the 100 kyr climate cycles of the past 800 000 years. The MBT has been identified in ice-core records, which indicate interglaciations became warmer with higher atmospheric CO2 levels after the MBT, and benthic oxygen isotope (δ18O) records, which suggest that post-MBT interglaciations had higher sea levels and warmer temperatures than pre-MBT interglaciations. It remains unclear, however, whether the MBT was a globally synchronous phenomenon that included other components of the climate system. Here, we further characterize changes in the climate system across the MBT …
Assessing Ground Penetrating Radar’S Ability To Image Subsurface Characteristics Of Icy Debris Fans In Alaska And New Zealand,
2018
Bucknell University
Assessing Ground Penetrating Radar’S Ability To Image Subsurface Characteristics Of Icy Debris Fans In Alaska And New Zealand, Robert W. Jacob, Jeffrey M. Trop, R. Craig Kochel
Faculty Journal Articles
Icy debris fans have recently been described as fan shaped depositional landforms associated with (or formed during) deglaciation, however, the subsurface characteristics remain essentially undocumented. We used ground penetrating radar (GPR) to non-invasively investigate the subsurface characteristics of icy debris fans (IDFs) at McCarthy Glacier, Alaska, USA and at La Perouse Glacier, South Island of New Zealand. IDFs are largely unexplored paraglacial landforms in deglaciating alpine regions at the mouths of bedrock catchments between valley glaciers and icecaps. IDFs receive deposits of mainly ice and minor lithic material through different mass-flow processes, chiefly ice avalanche and to a lesser extent …
Alpine Ice Evidence Of A Three-Fold Increase In Atmospheric Iodine Deposition Since 1950 In Europe Due To Increasing Oceanic Emissions,
2018
Université Grenoble Alpes-CNRS
Alpine Ice Evidence Of A Three-Fold Increase In Atmospheric Iodine Deposition Since 1950 In Europe Due To Increasing Oceanic Emissions, Michel Legrand, Joseph R. Mcconnell, Susanne Preunkert, Monica M. Arienzo, Nathan Chellman, Kelly E. Gleason, Tomás Sherwen, Mat J. Evans, Lucy J. Carpenter
Environmental Science and Management Faculty Publications and Presentations
Iodine is an important nutrient and a significant sink of tropospheric ozone, a climate-forcing gas and air pollutant. Ozone interacts with seawater iodide, leading to volatile inorganic iodine release that likely represents the largest source of atmospheric iodine. Increasing ozone concentrations since the preindustrial period imply that iodine chemistry and its associated ozone destruction is now substantially more active. However, the lack of historical observations of ozone and iodine means that such estimates rely primarily on model calculations. Here we use seasonally resolved records from an Alpine ice core to investigate 20th century changes in atmospheric iodine. After carefully considering …
Contrasting Patterns In Surface Ice Velocity Of Glaciers In The Nepal Himalayas,
2018
University of Alabama in Huntsville
Contrasting Patterns In Surface Ice Velocity Of Glaciers In The Nepal Himalayas, Katherine Strattman
Von Braun Symposium Student Posters
No abstract provided.
A Sub-Millennial Sediment Record Of Ice-Stream Retreat And Meltwater Storage In The Baltic Ice Lake During The Bølling-Allerød Interstadial,
2018
Montclair State University
A Sub-Millennial Sediment Record Of Ice-Stream Retreat And Meltwater Storage In The Baltic Ice Lake During The Bølling-Allerød Interstadial, April Lynn Kelly, Sandra Passchier
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
The rapid retreat of the Baltic Ice Stream and the development of the Baltic Ice Lake is assessed using data from sediment cores retrieved from three sub-basins in the southern Baltic Sea. Hydraulic piston coring by the International Ocean Discovery Program (IODP) recovered for the first time intact glacial lake sequences overlying diamictons and other ice-contact deposits at Sites M0063, M0064 and M0065. Based on the particle size and bulk sediment chemical composition the glacial lake sediments were subdivided into a proximal and a distal varve sequence. The origin of a dark, lithologically distinct horizon between the proximal and distal …
The 2015 Landslide And Tsunami In Taan Fiord, Alaska,
2018
Ground Truth Trekking, Seldovia, Alaska
The 2015 Landslide And Tsunami In Taan Fiord, Alaska, Bretwood Higman, Breanyn Macinnes, Colin Bloom
All Faculty Scholarship for the College of the Sciences
Glacial retreat in recent decades has exposed unstable slopes and allowed deep water to extend beneath some of those slopes. Slope failure at the terminus of Tyndall Glacier on 17 October 2015 sent 180 million tons of rock into Taan Fiord, Alaska. The resulting tsunami reached elevations as high as 193 m, one of the highest tsunami runups ever documented worldwide. Precursory deformation began decades before failure, and the event left a distinct sedimentary record, showing that geologic evidence can help understand past occurrences of similar events, and might provide forewarning. The event was detected within hours through automated seismological …
Decadal Topographic Change In The Mcmurdo Dry Valleys Of Antarctica: Thermokarst Subsidence, Glacier Thinning, And Transfer Of Water Storage From The Cryosphere To The Hydrosphere,
2018
Colgate University
Decadal Topographic Change In The Mcmurdo Dry Valleys Of Antarctica: Thermokarst Subsidence, Glacier Thinning, And Transfer Of Water Storage From The Cryosphere To The Hydrosphere, J. S. Levy, Andrew G. Fountain, M. K. Obryk, J. Telling, Craig Glennie, M. Gooseff, David J. Van Horn
Geology Faculty Publications and Presentations
Recent local-scale observations of glaciers, streams, and soil surfaces in the McMurdo Dry Valleys of Antarctica (MDV) have documented evidence for rapid ice loss, glacial thinning, and ground surface subsidence associated with melting of ground ice. To evaluate the extent,magnitude, and location of decadal-scale landscape change in the MDV, we collected airborne lidar elevation data in 2014–2015 and compared these data to a 2001–2002 airborne lidar campaign. This regional assessment of elevation change spans the recent acceleration of warming and melting observed by long-term meteorological and ecosystem response experiments, allowing us to assess the response of MDV surfaces to warming …
Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data,
2018
CUNY Graduate Center
Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta
Dissertations, Theses, and Capstone Projects
Surface melting over the Antarctic Peninsula (AP) plays a crucial role for the stability of ice shelves and dynamics of grounded ice, hence modulating the mass balance in a region of the world which is particularly sensitive to increasing surface temperatures. Understanding the processes that drive melting using surface energy and mass balance models is fundamental to improving estimates of current and future surface melting and associated sea level rise through ice-shelf collapse. This is even more important in view of the specific challenges presented by how circulation patterns over the topographically-complex Antarctic Peninsula, especially foehn winds, impact surface melt. …
Be-10/Be-9 Ratios Reflect Antarctic Ice Sheet Freshwater Discharge During Pliocene Warming,
2018
Benjamin Franklin Institute of Technology
Be-10/Be-9 Ratios Reflect Antarctic Ice Sheet Freshwater Discharge During Pliocene Warming, Rachel D. Valletta, Jane K. Willenbring, Sandra Passchier, Chiara Elmi
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
Along glaciated margins, ratios of meteoric cosmogenic beryllium‐10, 10Be, normalized to its stable isotope, 9Be, reflect an environmental signal, driven ultimately by climatic change. We explore the application of this isotopic pair as a proxy for East Antarctic Ice Sheet dynamics. We analyze 10Be/9Be in middle Pliocene glaciomarine sediments offshore the Wilkes Land Region (Integrated Ocean Drilling Program (IODP) Site U1361A) and examine our new record alongside existing biochemical/geochemical records (Ba/Al, opal %wt, εNd, and 87Sr/86Sr). 10Be/9Be ratios reach local maxima during pulsed, mild warming events and …
Rock Glaciers Of The Contiguous United States: Spatial Distribution, Cryospheric Context, And Riparian Vegetation,
2018
Portland State University
Rock Glaciers Of The Contiguous United States: Spatial Distribution, Cryospheric Context, And Riparian Vegetation, Gunnar Forrest Johnson
Dissertations and Theses
Continental-scale inventories of glaciers are available, but no analogous rock glacier inventories exist. We present the Portland State University Rock Glacier Inventory (n = 10,343) for the contiguous United States, then compare it to an existing inventory of contiguous United States glaciers (n = 853), identifying geographic and climatic factors affecting the spatial distributions observed. At least one rock glacier is identified in each of the 11 westernmost states, but nearly 90% are found in just five; Colorado (n = 3889), Idaho (n = 1723), Montana (n = 1780), Utah (n = 834), and Wyoming (n = 849). Glaciers are …
Geomorphology Of Icy Debris Fans: Delivery Of Ice And Sediment To Valley Glaciers Decoupled From Icecaps,
2018
Bucknell University
Geomorphology Of Icy Debris Fans: Delivery Of Ice And Sediment To Valley Glaciers Decoupled From Icecaps, R. Craig Kochel, Jeffrey M. Trop, Robert W. Jacob
Faculty Journal Articles
The pace and volume of mass flow processes contributing ice and sediment to icy debris fans (IDFs) were documented at sites in Alaska and New Zealand by integrating field observations, drone and time-lapse imagery, ground penetrating radar, and terrestrial laser scanning. Largely unstudied, IDFs are supraglacial landforms at the mouths of bedrock catchments between valley glaciers and icecaps. Time-lapse imagery recorded 300–2300 events reaching 15 fans during intervals from nine months to two years. Field observations noted hundreds of deposits trapped within catchments weekly that were later remobilized onto fans. Deposits were mapped on images taken three to four times …
The Impact Of Ground-Based Glaciogenic Seeding On A Shallow Stratiform Cloud Over The Sierra Madre In Wyoming: A Multi-Sensor Study Of The 3 March 2012 Case,
2018
Utah State University
The Impact Of Ground-Based Glaciogenic Seeding On A Shallow Stratiform Cloud Over The Sierra Madre In Wyoming: A Multi-Sensor Study Of The 3 March 2012 Case, Binod Pokharel, Bart Geerts, Xiaoqin Jing
Plants, Soils and Climate Student Research
A case study is presented of the impact of ground-based glaciogenic seeding on a shallow, lightly precipitating orographic storm with abundant supercooled cloud droplets, but few ice particles. The storm was observed on 3 March 2012 as part of the AgI (silver iodide) Seeding Cloud Impact Investigating (ASCII) experiment in Wyoming. The cloud base temperature was about -9°C, and cloud tops were at about -16°C. The high concentration of small droplets and low ice particle concentration lead to natural snow growth, mainly by vapor diffusion. The question addressed here is whether the injection of ice nucleating particles (AgI) enhanced snow …
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 …
Geochemical Fingerprints Of Glacially Eroded Bedrock From West Antarctica: Detrital Thermochronology, Radiogenic Isotope Systematics And Trace Element Geochemistry In Late Holocene Glacial-Marine Sediments,
2018
Imperial College London
Geochemical Fingerprints Of Glacially Eroded Bedrock From West Antarctica: Detrital Thermochronology, Radiogenic Isotope Systematics And Trace Element Geochemistry In Late Holocene Glacial-Marine Sediments, Patric Simões Pereira, Tina Van De Flierdt, Sidney R. Hemming, Samantha J. Hammond, Gerhard Kuhn, Stefanie A. Brachfeld, Cathleen Doherty, Claus-Dieter Hillenbrand
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
Geochemical provenance studies of glacial-marine sediments provide a powerful approach to describe subglacial geology, sediment transport pathways, and past ice sheet dynamics. The marine-based West Antarctic Ice Sheet (WAIS) is considered highly vulnerable to ocean warming and sea level rise that is likely to cause its rapid and irreversible retreat. Studies of its past response to climate change are hence essential for projecting its future behaviour. The application of radiogenic and trace element provenance studies for past ice sheet reconstructions requires surveying the geographic variability of geochemical compositions of glaciomarine sediments. In this study, we characterize the provenance of the …
Multi-Channel Ground-Penetrating Radar For The Continuous Quantification Of Snow And Firn Density, Depth, And Accumulation,
2018
Boise State University
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 …
