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Full-Text Articles in Glaciology

The Effects Of Sulfuric Acid On The Mechanical Properties Of Ice Single Crystals, Y. L. Trickett, I. Baker, P. M.S Pradhan Sep 2000

The Effects Of Sulfuric Acid On The Mechanical Properties Of Ice Single Crystals, Y. L. Trickett, I. Baker, P. M.S Pradhan

Dartmouth Scholarship

Ice single crystals of various orientations containing various concentrations of H2SO4 up to 11.5 ppm were cut from large pucks of laboratory-grown ice. Constant-strain-rate compression tests were performed on the doped ice crystals both at −20°C at an axial strain rate of 1 × 10−5 s−1 and at −10°C at 1 × 106 s−1. The stress–strain curves showed a linearly rising stress with increasing strain, followed by a sharply declining stress after reaching a peak. With further strain, the sharp decline in stress slowed. The tests clearly showed, for the first time, that this naturally occurring impurity dramatically decreases both …


In Situ Stress Tensor Measured In An Alaskan Glacier, W. Tad Pfeffer, Neil Humphrey, B. Amadei, Joel T. Harper, J. Wegmann Jan 2000

In Situ Stress Tensor Measured In An Alaskan Glacier, W. Tad Pfeffer, Neil Humphrey, B. Amadei, Joel T. Harper, J. Wegmann

Geosciences Faculty Publications

An experimental program at Worthington Glacier, Alaska, U.S.A., has yielded the first in situ measurements of the full stress tensor in glacier ice. Measurements were made with an array of stiff (low-compliance) normal-force sensors frozen into a borehole at 120 m depth. Freezing in temperate ice was accomplished by a down-hole heat exchanger which extracted heat at the rate of 15 W. Under slowly varying stress conditions, relaxation of stress anomalies by viscous creep following drilling of the hole and installation of the sensors allows for equilibration of measured stresses with far-field stresses. Equilibration of local and far-field stresses was …


The Link Between Climate Warming And Break-Up Of Ice Shelves In The Antarctic Peninsula, Ted A. Scambos, Christina L. Hulbe, Mark A. Fahnestock, Jennifer Bohlander Jan 2000

The Link Between Climate Warming And Break-Up Of Ice Shelves In The Antarctic Peninsula, Ted A. Scambos, Christina L. Hulbe, Mark A. Fahnestock, Jennifer Bohlander

Geology Faculty Publications and Presentations

A review of in situ and remote-sensing data covering the ice shelves of the Antarctic Peninsula provides a series of characteristics closely associated with rapid shelf retreat: deeply embayed ice fronts; calving of myriad small elongate bergs in punctuated events; increasing flow speed; and the presence of melt ponds on the ice-shelf surface in the vicinity of the break-ups. As climate has warmed in the Antarctic Peninsula region, melt-season duration and the extent of ponding have increased. Most break-up events have occurred during longer melt seasons, suggesting that meltwater itself, not just warming, is responsible. Regions that show melting without …


Revised Glacial Margins And Wisconsin Meltwater Paleoflood Hydrology In Slippery Rock Creek Basin, Central Western Pennsylvania, Gary John D'Urso Jan 2000

Revised Glacial Margins And Wisconsin Meltwater Paleoflood Hydrology In Slippery Rock Creek Basin, Central Western Pennsylvania, Gary John D'Urso

Graduate Theses, Dissertations, and Problem Reports (ETD)

Glacial margins mapped in Slippery Rock Creek basin during the 1950s are problematic. The number of sedimentological, mineralogical, petrological, and textural analyses used to distinguish glacial drifts in the southern portion of the basin were inadequate to resolve the margins. Furthermore, misidentification of man-made deposits as glacial drift led to erroneous interpretations regarding the extent and character of pre-Wisconsin glacial deposits, and appears to have influenced subsequent soil mapping. Canadian Shield erratic weathering was the primary tool used in this study to re-investigate the glacial margins. Erratics display one of three distinctive weathering rinds, so glacial deposits can be differentiated …