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Articles 1 - 30 of 31
Full-Text Articles in Glaciology
Discovery Of A Nanodiamond-Rich Layer In The Greenland Ice Sheet, Andrei V. Kurbatov, Paul Andrew Mayewski, Jorgen P. Steffensen, Allen West, Douglas J. Kennett, James P. Kennett, Ted E. Bunch, Mike Handley, Douglas S. Introne, Shane S. Que Hee, Christopher Mercer, Marilee Sellers, Feng Shen, Sharon B. Sneed, James C. Weaver, James H. Wittke, Thomas W. Stafford, John J. Donovan, Sujing Xie, Joshua J. Razink, Adrienne Stich, Charles R. Kinzie, Wendy S. Wolbach
Discovery Of A Nanodiamond-Rich Layer In The Greenland Ice Sheet, Andrei V. Kurbatov, Paul Andrew Mayewski, Jorgen P. Steffensen, Allen West, Douglas J. Kennett, James P. Kennett, Ted E. Bunch, Mike Handley, Douglas S. Introne, Shane S. Que Hee, Christopher Mercer, Marilee Sellers, Feng Shen, Sharon B. Sneed, James C. Weaver, James H. Wittke, Thomas W. Stafford, John J. Donovan, Sujing Xie, Joshua J. Razink, Adrienne Stich, Charles R. Kinzie, Wendy S. Wolbach
Earth Science Faculty Scholarship
We report the discovery in the Greenland ice sheet of a discrete layer of free nanodiamonds (NDs) in very high abundances, implying most likely either an unprecedented influx of extraterrestrial (ET) material or a cosmic impact event that occurred after the last glacial episode. From that layer, we extracted n-diamonds and hexagonal diamonds (lonsdaleite), an accepted ET impact indicator, at abundances of up to about 5!106 times background levels in adjacent younger and older ice. The NDs in the concentrated layer are rounded, suggesting they most likely formed during a cosmic impact through some process similar to carbon-vapor deposition or …
Policy And Science Of Geothermal Heat Use At Mcmurdo Station, Antarcrtica, Joe Alvine
Policy And Science Of Geothermal Heat Use At Mcmurdo Station, Antarcrtica, Joe Alvine
Department of Environmental Studies: Undergraduate Student Theses
My thesis research project deals with the use of geothermal heat in Antarctica. Currently it is not allowed due to article 7 of the 1991 Protocol on Environmental Protection that placed a 50 moratorium on the exploitation of mineral resources. The US main base in Antarctica, McMurdo Station is currently powered by diesel generators that are inefficient, cause environmental damage, and is expensive to run. By exploring alternative energy options, McMurdo Station can reduce its dependence on non-renewable energy sources. By determining the geothermal potential of McMurdo Station, this project explores the possibilities and benefits that would occur with the …
Geogram 2010, David J. Keeling Editor, Wku Department Of Geography And Geology
Geogram 2010, David J. Keeling Editor, Wku Department Of Geography And Geology
Earth, Environmental, and Atmospheric Sciences Publications
No abstract provided.
Comparison Of Ice Core Dissolved Organic Matter From A Greenland Ice Core By Nanospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Joshua Jeremiah Shiloh Marsh
Comparison Of Ice Core Dissolved Organic Matter From A Greenland Ice Core By Nanospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Joshua Jeremiah Shiloh Marsh
Chemistry & Biochemistry Theses & Dissertations
Recent studies of ice cores have embarked on the task of determining the classes of dissolved organic matter (DOM) present in melt-water from the cores collected in numerous locations in the northern and southern hemispheres. This DOM originally derives from wet precipitation and is thought to reflect atmospheric organic matter derived from anthropogenic and non-anthropogenic sources. Because the amount of DOM is so low, previous studies have necessarily used large sample volumes (greater than 500 mL) to concentrate sufficient ice core DOM necessary for mass spectral analysis. Solid phase extraction (SPE) with C18 resins was followed by evaporative concentration …
Collaborative Research: Grounding-Line Retreat In The Southern Ross Sea - Constraints From Scott Glacier, Brenda L. Hall
Collaborative Research: Grounding-Line Retreat In The Southern Ross Sea - Constraints From Scott Glacier, Brenda L. Hall
University of Maine Office of Research Administration: Grant Reports
This award supports a project to investigate late Pleistocene and Holocene changes in Scott Glacier, a key outlet glacier that flows directly into the Ross Sea just west of the present-day West Antarctic Ice Sheet (WAIS) grounding line. The overarching goals are to understand changes in WAIS configuration in the Ross Sea sector at and since the last glacial maximum (LGM) and to determine whether Holocene retreat observed in the Ross Embayment has ended or if it is still ongoing. To address these goals, moraine and drift sequences associated with Scott Glacier will be mapped and dated and ice thickness, …
Ice Layers As An Indicator Of Summer Warmth And Atmospheric Blocking In Alaska, Eric P. Kelsey, Cameron P. Wake, Karl Kreutz, Erich Osterberg
Ice Layers As An Indicator Of Summer Warmth And Atmospheric Blocking In Alaska, Eric P. Kelsey, Cameron P. Wake, Karl Kreutz, Erich Osterberg
Dartmouth Scholarship
No abstract provided.
Glaciotectonic Deformation Along The Valparaiso Upland In Southwest Michigan, Usa, Brian C. Bird
Glaciotectonic Deformation Along The Valparaiso Upland In Southwest Michigan, Usa, Brian C. Bird
Dissertations
Glaciotectonic deformation has been observed and analyzed across parts of the Valparaiso, Kendall, and Inner Kalamazoo Moraines in southwest Michigan, USA. Deformation structures such as folds and faults have been analyzed using techniques typically used by structural geologist along with the fabric of elongated clasts in the surficial diamicton. The structures are consistent with simple shear, horizontal compressional stresses, and pure shear. A series of drumlin fields exist along the western boundary of the study area. Direct investigation of the deformed sediments was conducted at a gravel pit in one of these drumlins. Lacustrine derived sediments interbedded with coarse sand …
Collaborative Proposal: 2000+ Year Detailed, Calibrated Climate Reconstruction From A South Pole Ice Core Set In An Antarctic - Global Scale Context, Paul Andrew Mayewski Dr., Karl J. Kreutz, Andrei V. Kurbatov
Collaborative Proposal: 2000+ Year Detailed, Calibrated Climate Reconstruction From A South Pole Ice Core Set In An Antarctic - Global Scale Context, Paul Andrew Mayewski Dr., Karl J. Kreutz, Andrei V. Kurbatov
University of Maine Office of Research Administration: Grant Reports
This award supports a project to examine an existing ice core of opportunity from South Pole (SPRESO core) to develop a 2000+ year long climate record. SPRESO ice core will be an annually dated, sub-annually-resolved reconstruction of past climate (atmospheric circulation, temperature, precipitation rate, and atmospheric chemistry) utilizing continuous, co-registered measurements (n=45) of: major ions, trace elements, and stable isotope series, plus selected sections for microparticle size and composition. The intellectual merit of this project relates to the fact that few 2000+ year records of this quality exist in Antarctica despite increasing scientific interest in this critical time period as …
Central New York Varve Chronology: A Suggestion For Quaternary Geologists, Thomas Bradley Walker
Central New York Varve Chronology: A Suggestion For Quaternary Geologists, Thomas Bradley Walker
Thomas Bradley Walker
Work done to build a chronology of deglaciation using varves has been the focus of a number of researchers in New England for many years. The locations employed to build their timeline have been quite useful to date. However, New England is not the only place in the Northeast conducive to studying the last deglaciation of North America. The discovery of a set of ice proximal varves in an ancient glacial lake, now a swamp, in Oswego County, central New York, has shown that some locations outside of New England would be suitable for similar studies. The land having been …
Timing Of Present And Future Snowmelt From High Elevations In Northwest Montana, Bonnie Jean Gillan, Joel T. Harper, Johnnie N. Moore
Timing Of Present And Future Snowmelt From High Elevations In Northwest Montana, Bonnie Jean Gillan, Joel T. Harper, Johnnie N. Moore
Geosciences Faculty Publications
The sensitivity of snowmelt-driven water supply to climate variability and change is difficult to assess in the mountain west, where strong climatic gradients coupled with complex topography are sampled by sparse ground measurements. We developed a model which ingests daily satellite imagery and meteorological data and is suitable for areas >1000 km2, yet captures spatial variability of snow accumulation and melt in steep mountain terrain.We applied the model for the years 2000–2008 to a 2900 km2 snowmelt-dominated watershed in NW Montana. We found that >25% of the basin’s snow water equivalent (SWE) accumulates above the highest measurement station and >70% …
Melting Ice And Sea Level Changes, Morton Sternheim
Melting Ice And Sea Level Changes, Morton Sternheim
IPY STEM Polar Connections
A simple experiment to demonstrate the effects of melting sea.
Thermohaline Circulation, Rob Snyder
Thermohaline Circulation, Rob Snyder
IPY STEM Polar Connections
Surface currents, such as the Gulf Stream, are pushed by the wind. Deep ocean currents, called the “Thermohaline Circulation”, are the result of changes in the density of water. In this activity you can investigate how differences in the temperature and salinity of water can produce deep ocean currents
Detecting Atmospheric Carbon Dioxide With Btb, Stephan Schneider
Detecting Atmospheric Carbon Dioxide With Btb, Stephan Schneider
IPY STEM Polar Connections
A study of the concentration of carbon dioxide gas in air samples requires an understanding of effective sampling techniques, the use of pH indicators, an understanding of chemical reactions that result on the formation of acidic compounds, and an understanding of the chemical processes that contribute to the composition and characteristics of Earth’s atmosphere.
Melting Ice And Sea Level Change, Morton Sternheim
Melting Ice And Sea Level Change, Morton Sternheim
IPY STEM Polar Connections
Global warming can melt snow or ice on Greenland, Antarctica, and other land areas. It can also melt floating ice in the Arctic Ocean. How do the two cases compare in changing sea levels?
Brine Rejection Activity, Beth Caissie, Rob Snyder
Brine Rejection Activity, Beth Caissie, Rob Snyder
IPY STEM Polar Connections
As salt water freezes, the salt is pushed out of solution through channels in the ice. This process is called brine rejection or brine exclusion. These channels are often used as microhabitats by ice algae, zooplankton, and even tiny fish. You can easily demonstrate what these channels look like.
Play Doh Coring Sampler Teacher Guide, Beth Caissie
Play Doh Coring Sampler Teacher Guide, Beth Caissie
IPY STEM Polar Connections
Sediment cores are one of the most valuable types of samples for researchers who would like to learn about past climate or ecological changes. Cores can be retrieved from lakes, marshes, swamps, fields, and the ocean. The layers often reveal striking changes in color (see photos) reflecting changing sediment composition (i.e. more clay deposition or more microfossil s). This easy activity illustrates the basic geologic principle that horizontal layers of sediment become older the deeper you go below the Earth’s surface (Law of Superposition). Each layer contains sediment, fossils and organic matter etc. that can inform us about past changes …
Sea Ice Food Webs—Hands On Sampler Teacher Guide, Beth Caissie
Sea Ice Food Webs—Hands On Sampler Teacher Guide, Beth Caissie
IPY STEM Polar Connections
This activity is a variation on a food web game that I’ve seen played many times before, but it is adapted to reflect a sea ice food web and show the many organisms that are intimately connected to polar bears.
Glacier Goo Activity, Beth Caissie
Glacier Goo Activity, Beth Caissie
IPY STEM Polar Connections
We provided the students with background information about what a glacier is, where they are, how they move. Then split the students into four groups each tasked with a question to answer through experimentation
Group s 1 and 2: How does temperature change the way a glacier flows? (we provided frozen, and room temperature goo, and a microwave for heating the goo)
Groups 3 and 4: How does friction or obstacles change the way a glacier flows? (we provided different pvc tubes—tubes with nothing done to them, tubes with paintable sand applied to them, and tubes with rocks glued to …
Carbon Travels Game, Marie Silver
Carbon Travels Game, Marie Silver
IPY STEM Polar Connections
Carbon cycle game.
Proportions for this activity are based LOOSELY on data from the Exploring the Environment website http://davem2.cotf.edu/ete/modules/carbon/effig11_full.html
They have a brief overview of the carbon cycle at http://davem2.cotf.edu/ete/modules/carbon/efcarbon.html
Recommended Books, Holly Hargraves, Ray Bradley
Recommended Books, Holly Hargraves, Ray Bradley
IPY STEM Polar Connections
No abstract provided.
Teacher’S Guide: Penguins Of Antarctic Region, Marie Silver
Teacher’S Guide: Penguins Of Antarctic Region, Marie Silver
IPY STEM Polar Connections
These activities help to connect science learning with real world issues through a study of the Antarctic region. By studying the penguins of the South Pole region you can tap students’ interest in a charismatic macrospecies through demonstrating their adaptation to ongoing climate changes and human activity. A number of current research projects at Antarctic research stations can be accessed online and the data used to demonstrate key concepts of feeding behavior, migration, breeding and population dynamics. The attached activity is in three parts and includes one hands-on demonstration, several mapping exercises and some data interpretation. These activities also provide …
A New Technique For Firn Grain-Size Measurement Using Sem Image Analysis, N.E. Spaulding, D.A. Meese, I. Baker, P.A. Mayewski
A New Technique For Firn Grain-Size Measurement Using Sem Image Analysis, N.E. Spaulding, D.A. Meese, I. Baker, P.A. Mayewski
Dartmouth Scholarship
Firn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Gow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the …
Climate In The Southern Sawatch Range And Elk Mountains, Colorado, U.S.A., During The Last Glacial Maximum: Inferences Using A Simple Degree-Day Model, Keith A. Brugger
Climate In The Southern Sawatch Range And Elk Mountains, Colorado, U.S.A., During The Last Glacial Maximum: Inferences Using A Simple Degree-Day Model, Keith A. Brugger
Geology Publications
Equilibrium-line altitudes (ELAs) were determined from reconstructions of 22 paleoglaciers at their extent during the local last glacial maximum (LGM) using the accumulation-area method. LGM ELAs thus derived ranged from 2980 to 3560 m and follow a statistically significant regional trend of rising ~4.5 m km-1 to the east. Two approaches using a degree-day model were used to infer LGM climate by finding plausible combinations of temperature and precipitation change that (1) would be required to lower ELAs to their mean LGM values in both the Taylor Park/eastern Elk Mountains region and western Elk Mountains, and (2) provide steady-state …
Women In Glaciology, An Historical Perspective, Christina L. Hulbe, Weili Wang, Simon Ommanney
Women In Glaciology, An Historical Perspective, Christina L. Hulbe, Weili Wang, Simon Ommanney
Geology Faculty Publications and Presentations
Women's history in glaciology extends as far back in time as the discipline itself, although their contributions to the scientific discourse have for all of that history been constrained by the sociopolitical contexts of the times. The first Journal of Glaciology paper authored by a woman appeared in 1948, within a year of the founding of the Journal, but it was not until the 1980s that women produced more than a few percent of Journal and Annals of Glaciology papers. Here international perspectives on women's participation in the sciences are presented in order to establish an economic and sociopolitical context …
Grounding-Line Basal Melt Rates Determined Using Radar-Derived Internal Stratigraphy, Ginny Catania, Christina L. Hulbe, Howard Conway
Grounding-Line Basal Melt Rates Determined Using Radar-Derived Internal Stratigraphy, Ginny Catania, Christina L. Hulbe, Howard Conway
Geology Faculty Publications and Presentations
We use ice-penetrating radar data across grounding lines of Siple Dome and Roosevelt Island, Antarctica, to measure the spatial pattern, magnitude and duration of sub-ice-shelf melting at these locations. Stratigraphic layers across the grounding line show, in places, a large-amplitude downwarp at, or slightly downstream of, the grounding line due to sub-ice-shelf basal melting. Localized downwarping indicates that melting is transient; melt rates, or the grounding line position, have changed within a few hundred years in order to produce the observed stratigraphy. Elsewhere, no meltrelated stratigraphic signature is preserved. In part, heterogeneity in the amount of sub-ice-shelf melt is due …
Propagation Of Long Fractures In The Ronne Ice Shelf Investigated Using A Numerical Model Of Fracture Propagation, Christina L. Hulbe, Christine Marie Ledoux, Kenneth M. Cruikshank
Propagation Of Long Fractures In The Ronne Ice Shelf Investigated Using A Numerical Model Of Fracture Propagation, Christina L. Hulbe, Christine Marie Ledoux, Kenneth M. Cruikshank
Geology Faculty Publications and Presentations
Long rifts near the front of the Ronne Ice Shelf, Antarctica, are observed to begin as fractures along the lateral boundaries of outlet streams feeding the shelf. These flaws eventually become the planes along which tabular icebergs calve. The fractures propagate laterally as they advect through the shelf, with orientations that can be explained by the glaciological stress field. Fracture length remains constrained over much of the advective path, and locations of crack tip arrest are observed to coincide with structural boundaries, such as suture zones between ice from adjacent outlet glaciers. Geomechanical principles and numerical models demonstrate that in …
A Dynamic Physical Model For Soil Temperature And Water In Taylor Valley, Antarctica, H. W. Hunt, Andrew G. Fountain, Peter T. Doran, Hassan J. Basagic
A Dynamic Physical Model For Soil Temperature And Water In Taylor Valley, Antarctica, H. W. Hunt, Andrew G. Fountain, Peter T. Doran, Hassan J. Basagic
Geography Faculty Publications and Presentations
We developed a simulation model for terrestrial sites including sensible heat exchange between the atmosphere and ground surface, inter- and intra-layer heat conduction by rock and soil, and shortwave and longwave radiation. Water fluxes included snowmelt, freezing/thawing of soil water, soil capillary flow, and vapour flows among atmosphere, soil, and snow. The model accounted for 96-99% of variation in soil temperature data. No long-term temporal trends in soil temperature were apparent. Soil water vapour concentration in thawed surface soil in summer often was higher than in frozen deeper soils, leading to downward vapour fluxes. Katabatic winds caused a reversal of …
Climate Investigations Using Ice Sheet And Mass Balance Models With Emphasis On North American Glaciation, Sean David Birkel
Climate Investigations Using Ice Sheet And Mass Balance Models With Emphasis On North American Glaciation, Sean David Birkel
Electronic Theses and Dissertations
This dissertation describes the application of the University of Maine Ice Sheet Model (UM-ISM) and Environmental Change Model (UM-ECM) to understanding mechanisms of ice-sheet/climate integration during ice ages. The UM-ECM, written by the author for this research, calculates equilibrium biome and snow/ice mass balance solutions for the globe based on modern input climatology and user-defined parameter values. The program was produced in conjunction with a National Science Foundation ITEST grant meant to seed inquiry-based classroom study of Earth systems using computer models. To that end, the UM-ECM serves as both a research and teaching tool. The model has a web-based …
Higher-Order Physic For Modeling Ice Streams In Ice Sheets, Debra A. Kenneway
Higher-Order Physic For Modeling Ice Streams In Ice Sheets, Debra A. Kenneway
Electronic Theses and Dissertations
Ice streams are transitional between inland glaciers and ice shelves. Hence no stresses can be neglected. Ice streams are important dynamic features of a glacier; it is well known that ice streams drain up to 90% of the ice from an ice sheet. Herein I model ice streams as a multiphysics system of coupled components. This includes treating ice as a non-Newtonian fluid since empirical measurements show a power law relation between stress and strain rate. Sliding is a physical feature that must be included. This is done with a novel approach to sliding by way of a slippery layer. …
Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman
Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
In this study, we report measurements of CFC-12 (CCl2F2) in firn air and in air extracted from shallow ice cores from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, some of the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the ice core and firn air data provide evidence for the presence of modern air entrapped in the shallow ice core samples that likely contained open pores at the time of collection. We propose that this is due to closure of the open pores …