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Articles 1 - 21 of 21
Full-Text Articles in Earth Sciences
Assessment Of The Record Of The 1982 El Chichón Eruption As Preserved In Greenland Snow, Gregory A. Zielinski, Jack E. Dibb, Qinzhao Yang, Paul Andrew Mayewski, Sallie Whitlow, Mark S. Twickler, Mark S. Germani
Assessment Of The Record Of The 1982 El Chichón Eruption As Preserved In Greenland Snow, Gregory A. Zielinski, Jack E. Dibb, Qinzhao Yang, Paul Andrew Mayewski, Sallie Whitlow, Mark S. Twickler, Mark S. Germani
Earth Science Faculty Scholarship
Variability in the SO 4 2 - and Cl− time series for the 1980s from 12 shallow snow pits across the Greenland ice sheet is used to evaluate the record of the 1982 El Chichón eruption and the potential for recording a moderate northern equatorial eruption in a single Greenland ice core. Composition of volcanic glass found in spring 1983 snow in one of the pits in the Summit region matches that from El Chichón glass, thereby verifying the deposition of material from the eruption. High Na+ and Cl− concentrations in this same layer probably represent deposition …
On The Strain-Rate Sensitivity Of Columnar Ice, M. E. Manley, E. M. Schulson
On The Strain-Rate Sensitivity Of Columnar Ice, M. E. Manley, E. M. Schulson
Dartmouth Scholarship
A power law relation between stress and strain rate of the form σ ∝ ε̇1/n was used to describe the response to strain rate of S1 ice loaded across the columns at -10°C. The rate exponent, n, decreased with increasing strain from about 4.6 at an observed peak on the load displacement curve to approximately 2.6 at a shortening of 2%. Analysis of these results and of the results of other authors on different forms of ice deformed at the same temperature suggests that the power law exponent, n, is proportional to Fc/Fg. The parameter Fc/Fg is the far-field basal …
Preface, Claus Hammer, Paul Andrew Mayewski, David Peel, Minze Stuiver
Preface, Claus Hammer, Paul Andrew Mayewski, David Peel, Minze Stuiver
Earth Science Faculty Scholarship
This special issue of the Journal of Geophysical Research presents 47 papers developed from research on the two deep ice cores drilled in central Greenland during the years 1989-1993 by the U.S. Greenland Ice Sheet Project 2 (GISP2) and the European Greenland Ice Core Program (GRIP). In this "grand experiment," two large ice-core-drilling programs were combined. A major reason was to validate the presence of fast climate oscillations that could not be verified by a single deep ice core.
A 110,000-Year History Of Change In Continental Biogenic Emissions And Related Atmospheric Circulation Inferred From The Greenland Ice Sheet Project Ice Core, L. D. Meeker, Paul Andrew Mayewski, M. S. Twickler, S. I. Whitlow, D. Meese
A 110,000-Year History Of Change In Continental Biogenic Emissions And Related Atmospheric Circulation Inferred From The Greenland Ice Sheet Project Ice Core, L. D. Meeker, Paul Andrew Mayewski, M. S. Twickler, S. I. Whitlow, D. Meese
Earth Science Faculty Scholarship
The 110,000-year record of ammonium concentrations from the Greenland Ice Sheet Project 2 (GISP2) ice core provides the basis for an analysis of terrestrial biological production and atmospheric circulation patterns involved in the transport of biologically produced ammonium to the Greenland atmosphere. The directly measured concentration series was selected for analysis, rather than that of estimated ammonium flux, after a detailed analysis of the relationship among ice core glaciochemical concentrations and a high-resolution simultaneous record of snow accumulation from the GISP2 core. Analysis of the ammonium concentration series shows that maxima in background levels of ammonium in the Greenland atmosphere …
The Co2 Concentration Of Air Trapped In Greenland Ice Sheet Project 2 Ice Formed During Periods Of Rapid Climate Change, H. J. Smith, M. Wahlen, D. Mastroianni, K. Taylor, Paul Andrew Mayewski
The Co2 Concentration Of Air Trapped In Greenland Ice Sheet Project 2 Ice Formed During Periods Of Rapid Climate Change, H. J. Smith, M. Wahlen, D. Mastroianni, K. Taylor, Paul Andrew Mayewski
Earth Science Faculty Scholarship
The CO2 content of air occluded in Greenland Ice Sheet Project 2 (GISP2) ice formed over two separate intervals of rapidly changing climate, centered at approximately 46 and 63 kyr B. P., is as much as 90 ppm more during warm periods (interstadials) than during cold periods (stadials). These CO2 variations are superimposed on changes in annual layer thickness and δ18O of the ice and do not show the 200- to 700-year offsets which would be expected for concurrent variations in the atmosphere and the ice. The CO2 concentrations during the stadials are similar to …
Electrical Measurements On The Greenland Ice Sheet Project 2 Core, Kendrick C. Taylor, Richard B. Alley, Gregg W. Lamorey, Paul Andrew Mayewski
Electrical Measurements On The Greenland Ice Sheet Project 2 Core, Kendrick C. Taylor, Richard B. Alley, Gregg W. Lamorey, Paul Andrew Mayewski
Earth Science Faculty Scholarship
The Greenland Ice Sheet Project 2 (GISP2) electrical conductivity measurement (ECM) record is an indication of the concentration of H+ in the core. The ECM detected seasonal variations in the nitrate concentration of the core which were used to assist in dating the core by annual layer counting. Volcanic eruptions that produce acidic aerosols are recorded in the ECM record. Evidence of biomass burning is detected by the ECM because fire-related ammonium emissions neutralize the acids in the core. Rapid climate transitions associated with the Younger Dryas and Dansgaard/Oeschger interstadial events alter the concentration of alkaline dust and are detected …
Paleoclimatic Variability Inferred From The Spectral Analysis Of Greenland And Antarctic Ice-Core Data, R. Yiou, K. Fuher, L. D. Meeker, J. Jouzel, S. Johnsen, Paul Andrew Mayewski
Paleoclimatic Variability Inferred From The Spectral Analysis Of Greenland And Antarctic Ice-Core Data, R. Yiou, K. Fuher, L. D. Meeker, J. Jouzel, S. Johnsen, Paul Andrew Mayewski
Earth Science Faculty Scholarship
Paleoclimate variations occur at various time scales, between a few centuries for the Heinrich events and several hundreds of millenia for the glacial to interglacial variations. The recent ice cores from Greenland (Greenland Ice Core Project and Greenland Ice Sheet Project 2) and Antarctica (Vostok) span at least one glacial oscillation and provide many opportunities to investigate climate variations with a very fine resolution. The joint study of cores from both hemispheres allows us to distinguish between the sources of variability and helps to propose mechanisms of variations for the different time scales involved. The climate proxies we analyze are …
The Greenland Ice Sheet Project 2 Depth-Age Scale: Methods And Results, D. A. Meese, A. J. Gow, R. B. Alley, G. A. Zielinski, P. M. Grootes, M. Ram, K. C. Taylor, Paul Andrew Mayewski, J. F. Bolzan
The Greenland Ice Sheet Project 2 Depth-Age Scale: Methods And Results, D. A. Meese, A. J. Gow, R. B. Alley, G. A. Zielinski, P. M. Grootes, M. Ram, K. C. Taylor, Paul Andrew Mayewski, J. F. Bolzan
Earth Science Faculty Scholarship
The Greenland Ice Sheet Project 2 (GISP2) depth-age scale is presented based on a multiparameter continuous count approach, to a depth of 2800 m, using a systematic combination of parameters that have never been used to this extent before. The ice at 2800 m is dated at 110,000 years B.P. with an estimated error ranging from 1 to 10% in the top 2500 m of the core and averaging 20% between 2500 and 2800 m. Parameters used to date the core include visual stratigraphy, oxygen isotopic ratios of the ice, electrical conductivity measurements, laser-light scattering from dust, volcanic signals, and …
Volcanic Aerosol Records And Tephrochronology Of The Summit, Greenland, Ice Cores, Gregory A. Zielinski, Paul Andrew Mayewski, L. David Meeker, Karl Grönvold, Mark D. Germani, Sallie Whitlow, Mark S. Twickler, Kendrick Taylor
Volcanic Aerosol Records And Tephrochronology Of The Summit, Greenland, Ice Cores, Gregory A. Zielinski, Paul Andrew Mayewski, L. David Meeker, Karl Grönvold, Mark D. Germani, Sallie Whitlow, Mark S. Twickler, Kendrick Taylor
Earth Science Faculty Scholarship
The recently collected Greenland Ice Sheet Project 2 (GISP2) and Greenland Ice Core Project ice cores from Summit, Greenland, provide lengthy and highly resolved records of the deposition of both the aerosol (H2SO4) and silicate (tephra) components of past volcanism. Both types of data are very beneficial in developing the hemispheric to global chronology of explosive volcanism and evaluating the entire volcanism-climate system. The continuous time series of volcanic SO42− for the last 110,000 years show a strong relationship between periods of increased volcanism and periods of climatic change. The greatest number of volcanic …
Major Features And Forcing Of High-Atitude Northern Hemisphere Atmospheric Circulation Using A 110,000-Year-Long Glaciochemical Series, Paul Andrew Mayewski, Loren D. Meeker, Mark S. Twickler, Sallie Whitlow, Qinzhao Yang, W. Berry Lyons, Michael Prentice
Major Features And Forcing Of High-Atitude Northern Hemisphere Atmospheric Circulation Using A 110,000-Year-Long Glaciochemical Series, Paul Andrew Mayewski, Loren D. Meeker, Mark S. Twickler, Sallie Whitlow, Qinzhao Yang, W. Berry Lyons, Michael Prentice
Earth Science Faculty Scholarship
The Greenland Ice Sheet Project 2 glaciochemical series (sodium, potassium, ammonium, calcium, magnesium, sulfate, nitrate, and chloride) provides a unique view of the chemistry of the atmosphere and the history of atmospheric circulation over both the high latitudes and mid-low latitudes of the northern hemisphere. Interpretation of this record reveals a diverse array of environmental signatures that include the documentation of anthropogenically derived pollutants, volcanic and biomass burning events, storminess over marine surfaces, continental aridity and biogenic source strength plus information related to the controls on both high- and low-frequency climate events of the last 110,000 years. Climate forcings investigated …
Methanesulfonate In The Greenland Ice Sheet Project 2 Ice Core, E. S. Saltzman, P-Y. Whung, Paul Andrew Mayewski
Methanesulfonate In The Greenland Ice Sheet Project 2 Ice Core, E. S. Saltzman, P-Y. Whung, Paul Andrew Mayewski
Earth Science Faculty Scholarship
In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmospheric oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmospheric loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day [Hansson and Saltzman, 1993]. We conclude that the flux of biogenic sulfur from the North Atlantic Ocean …
Major Features Of Glaciochemistry Over The Last 110,000 Years In The Greenland Ice Sheet Project 2 Ice Core, Qinzhao Yang, Paul Andrew Mayewski, Marks S. Twickler, Sallie Whitlow
Major Features Of Glaciochemistry Over The Last 110,000 Years In The Greenland Ice Sheet Project 2 Ice Core, Qinzhao Yang, Paul Andrew Mayewski, Marks S. Twickler, Sallie Whitlow
Earth Science Faculty Scholarship
Major chemical species (Cl−, NO 3 - , SO 4 2 - , Na+, NH 4 + , K+, Mg2+, Ca2+) and δ18O covering the last 110,000 years from the Greenland Ice Sheet Project 2 (GISP2) ice core were utilized in this study in order to reconstruct the soluble chemistry of the atmosphere over Greenland and interpret major climate events that have affected the region. During the Holocene the major chemical species and δ18O do not display any significant relationship. However, a strong inverse correlation was …
Glaciochemistry Of Polar Ice Cores: A Review, Michel Legrand, Paul Andrew Mayewski
Glaciochemistry Of Polar Ice Cores: A Review, Michel Legrand, Paul Andrew Mayewski
Earth Science Faculty Scholarship
Human activities have already modified the chemical composition of the natural atmosphere even in very remote regions of the world. The study of chemical parameters stored in solid precipitation and accumulated on polar ice sheets over the last several hundred thousand years provides a unique tool for obtaining information on the composition of the preindustrial atmosphere and its natural variability over the past. This paper deals with the chemistry of polar ice focused on the soluble mineral (Na+, NH4+, K+, Ca++, Mg++, H+, F−, Cl …
Researchers Pool Knowledge About Antarctic Dry Valleys, Andrew G. Fountain, Sarah Spaulding
Researchers Pool Knowledge About Antarctic Dry Valleys, Andrew G. Fountain, Sarah Spaulding
Geology Faculty Publications and Presentations
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.
Across-Column Cracks And Axial Splits In S2 Saline Ice Under Compression, E. M. Schulson, S. Qi, J. S. Melton, E. T. Gratz
Across-Column Cracks And Axial Splits In S2 Saline Ice Under Compression, E. M. Schulson, S. Qi, J. S. Melton, E. T. Gratz
Dartmouth Scholarship
Experiments on plate-like specimens have established that across-column cracks from within S2 (columnar) salt-water ice when compressed uniaxially along a direction inclined to the long axis of the grains. Wing cracks initiate from the across-column cracks and lengthen into axial splits when the ice is rapidly deformed; correspondingly; the macroscopic behavior changes from ductile to brittle. The across-column cracking is attributed to grain-boundary sliding, and the splitting to the suppression of crack-tip creep.
Glaciochemical Studies At Siple Dome, West Antarctica, During The 1996–1997 Season, Karl J. Kreutz, Paul Andrew Mayewski, Mark S. Twickler, Sallie I. Whitlow, L. David Meeker
Glaciochemical Studies At Siple Dome, West Antarctica, During The 1996–1997 Season, Karl J. Kreutz, Paul Andrew Mayewski, Mark S. Twickler, Sallie I. Whitlow, L. David Meeker
Earth Science Faculty Scholarship
Deep ice cores collected from the interior of the west antarctic ice sheet and the interice stream ridges along the Siple Coast potentially contain long time-series records of Southern Hemisphere environmental change. One such location is Siple Dome, an approximately l20-kilometer (km) x 250-km ice dome located between ice streams C and D (figure 1). Because of promising results from reconnaissance glaciochemical (Mayewski, Twickler, and Whitlow 1995) and geophysical (Raymond et al. 1995) research, current U.S. deep ice-coring efforts are focused in the area. Drilling at Siple Dome is advantageous for several reasons, including the site's relatively simple geometry and …
Grand Tour-Part 2: Petrogenesis And Thermal Evolution Of Deep Continental-Crust: The Record From The East Humboldt Range, Nevada, Allen J. Mcgrew, Mark T. Peters
Grand Tour-Part 2: Petrogenesis And Thermal Evolution Of Deep Continental-Crust: The Record From The East Humboldt Range, Nevada, Allen J. Mcgrew, Mark T. Peters
Geology Faculty Publications
The northern part of the East Humboldt Range, Nevada, provides a rare opportunity to explore the petrogenetic environment of deep levels in the middle crust during both large-scale Mesozoic contraction and Cenozoic regional extension. On this segment of the field trip, we will explore evidence bearing on the character of the metamorphic and magmatic history of this terrane, and attempt to link these constraints to the rheology and tectonic evolution of the middle crust during the Mesozoic and Cenozoic.
The Grand Tour Of The Ruby-East Humboldt Metamorphic Core Complex, Northeastern Nevada: Part 1-Introduction & Road Log, Arthur W. Snoke, Keith A. Howard, Allen J. Mcgrew, Bradford R. Burton, Calvin G. Barnes, Mark T. Peters, James E. Wright
The Grand Tour Of The Ruby-East Humboldt Metamorphic Core Complex, Northeastern Nevada: Part 1-Introduction & Road Log, Arthur W. Snoke, Keith A. Howard, Allen J. Mcgrew, Bradford R. Burton, Calvin G. Barnes, Mark T. Peters, James E. Wright
Geology Faculty Publications
The purpose of this geological excursion is to provide an overview of the multiphase developmental history of the Ruby Mountains and East Humboldt Range, northeastern Nevada. Although these mountain ranges are commonly cited as a classic example of a Cordilleran metamorphic core complex developed through large-magnitude, mid-Tertiary crustal extension, a preceding polyphase Mesozoic contractional history is also well preserved in the ranges. An early phase of this history involved Late Jurassic two-mica granitic magmatism, high-temperature but relatively low-pressure metamorphism, and polyphase deformation in the central Ruby Mountains. In the northern Ruby Mountains and East Humboldt Range, a Late Cretaceous history …
A Strategy For Monitoring Glaciers, Andrew G. Fountain, Robert M. Krimmel, Dennis C. Trabant
A Strategy For Monitoring Glaciers, Andrew G. Fountain, Robert M. Krimmel, Dennis C. Trabant
Geography Faculty Publications and Presentations
Glaciers are important features in the hydrologic cycle and affect the volume, variability, and water quality of runoff. Assessing and predicting the effect of glaciers on water resources require a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing. Ideally, each glacierized region of the United States would have such a network of glaciers. The intensively studied glacier provides a detailed understanding of the physical processes and their temporal …
Sem Analysis Of Quartz Sand Grain Surface Textures Indicates Alluvial/Colluvial Origin Of The Quaternary "Glacial" Boulder Clays At Huangshan (Yellow Mountain), East-Central China, P. E. Helland, Pei-Hua Huang, Robert F. Diffendal Jr.
Sem Analysis Of Quartz Sand Grain Surface Textures Indicates Alluvial/Colluvial Origin Of The Quaternary "Glacial" Boulder Clays At Huangshan (Yellow Mountain), East-Central China, P. E. Helland, Pei-Hua Huang, Robert F. Diffendal Jr.
School of Natural Resources: Faculty Publications
Geomorphic features and Pleistocene deposits on Huangshan have been attributed to glaciation. Recent reassessment questions this interpretation. As part of the reassessment, quartz sand grains from deposits identified as glacial boulder clays (till composed of boulders in a clay or silt matrix) were analyzed by scanning electron microscope for evidence of their sedimentary history. Surface textures found on the boulder-clay grains were compared with those on grains with known sedimentary histories including glacial, grus, colluvial, and alluvial grains. The analysis shows that the grains lack typical glacial textures. The surface textures present indicate a complex history. Non-uniformly weathered grain surfaces …
The Impact Of Glacier Recession Upon The Discharge Of The Bow River Above Banff, Alberta, 1951-1993, Christopher Dennis Hopkinson
The Impact Of Glacier Recession Upon The Discharge Of The Bow River Above Banff, Alberta, 1951-1993, Christopher Dennis Hopkinson
Theses and Dissertations (Comprehensive)
Three methods have been used to explore the volumetric change of glaciers in the Bow Basin above Banff for the years 1951 to 1993. Using aerial photography, the extent of glacier covers for the two years were mapped at a scale of 1:50,000. The first volumetric calculation of glacier loss was based on inventory criteria; the second a hyposgraphic curve method based on Young’s investigations in Mistaya Basin (1991) and the third stereo air photogrammetry and DEM comparisons using computer software. These methods were applied to the highly glacierized Hector Lake catchment within the Bow Valley and then extrapolated up …