Physical Sciences and Mathematics Commons^™

Subsurface Glacial Geology Of The Area Between The Tekonsha And Kalamazoo Moraines, Kalamazoo County, Michigan, Kim Finkbeiner

Masters Theses

Cross sections profiling the stratigraphy of the glacial sediments were created using the geological logs recorded on water well records. Glacial sediments in the study area comprise a large outwash complex between two moraines. The surficial landforms are the result of the last Wisconsinan advance and retreat through the area.

Cross sections contructed for this project reveal at least three major till units. An additional till unit contains a weathered soil sequence. Therefore, it is possible that this paleosol represents the Sangamon Interglacial period between the Wisconsinan and Illinoian stages. No obvious evidence of movement of the Saginaw Lobe remains …

Climatic Impact Of The A.D. 1783 Asama (Japan) Eruption Was Minimal: Evidence From The Gisp2 Ice Core, G. A. Zielinski, R. J. Fiacco, Paul Andrew Mayewski, L. D. Meeker, S. Whitlow, M. S. Twickler, M. S. Germani, K. Endo, M. Yasui

Earth Science Faculty Scholarship

Assessing the climatic impact of the A.D. 1783 eruption of Mt. Asama, Japan, is complicated by the concurrent eruption of Laki, Iceland. Estimates of the stratospheric loading of H₂SO₄ for the A.D. 1108 eruption of Asama derived from the SO₄²⁻ time series in the GISP2 Greenland ice core indicate a loading of about 10.4 Tg H₂SO₄ with a resulting stratospheric optical depth of 0.087. Assuming sulfur emissions from the 1783 eruption were only one‐third of the 1108 event yields a H₂SO₄ loading value of 3.5 Tg and a stratospheric …

Record Drilling Depth Struck In Greenland, Paul Andrew Mayewski, M. S. Twickler, J. E. Dibb, M. Wumkes, J. Klinck, J. S. Putscher, K. C. Taylor, D. A. Meese, E. D. Waddington, R. B. Alley, P. M. Grootes, M. Ram, M. Wahlen, A. T. Wilson

Earth Science Faculty Scholarship

On July 1, 1993, after 5 years of drilling, the Greenland Ice Sheet Project (GISP2) penetrated several meters of silty ice and reached bedrock at a depth of 3053.4 m. It then penetrated 1.5 m into the bedrock, producing the deepest ice core ever recovered (Figure 1).

In July 1992, a nearby European ice coring effort, the Greenland Ice Core Project (GRIP), reached an ice depth of 3028.8 m, providing more than 250,000 years of record. Comparisons between these ice core records have already demonstrated the remarkable reproducibility of the upper ∼90% of the records unparalleled view of climatic and …

Two-Hundred-Year Record Of Biogenic Sulfur In A South Greenland Ice Core (20d), P. Y. Whung, E. S. Saltzman, M. J. Spencer, Paul Andrew Mayewski, N. Gundestrup

Earth Science Faculty Scholarship

The concentration of methanesulfonic acid (MSA) was determined in a shallow south central Greenland ice core(20D). This study provides a high-resolution record of the DMS-derived biogenic sulfur in Greenland precipitation over the past 200 years. The mean concentration of MSA is 3.30 ppb(σ = 2.38 ppb,n = 1134). The general trend of MSA is an increase from 3.01 to 4.10 ppb between 1767 and 1900, followed by a steady decrease to 2.34 ppb at the present time. This trend is in marked contrast to that of non-sea-salt sulfate (nss SO₄^2-), which increases dramatically after 1900 due to …

Ductile Saline Ice, G. A. Kuehn, E. M. Schulson

Dartmouth Scholarship

Experiments have shown that tensile ductility of about 5% or more can be imparted to columnar, saline ice by pre-compressing the material by about 3.5%. This effect is similar to that observed in granular, fresh-water ice and is attributed to the operation of both dislocation creep and diffusion creep within that part of the matrix which recrystallized during the pre-compressive deformation.