Earth Sciences Commons^™

Stratigraphic Analysis Of Diamicton Units In North-Central St. Joseph County, Michigan, Andrew C. Flint

Masters Theses

Seven subsurface glacial diamicton units, including a paleosol, have been characterized from two borings in north-central St. Joseph County, Michigan. These units have been characterized in terms of their clay mineralogy, texture, color, and stratigraphic position. t-Tests confirm that each unit displays a significant difference in mean 7A/10A peak height ratio from all other units.

Unit 4, informally called the Gray Marker tilt has been correlated between borings in this study and to the findings of others (Gardner, 1997, Nicks, in preparation). The Newbury till described by the Indiana Geological Survey (unpublished data) may also correlate to Unit 4, raising …

Maximum Temperature Trends In The Himalaya And Its Vicinity: An Analysis Based On Temperature Records From Nepal For The Period 1971-94, Arun B. Shrestha, Camerson P. Wake, Paul Andrew Mayewski, Jack E. Dibb

Earth Science Faculty Scholarship

Analyses of maximum temperature data from 49 stations in Nepal for the period 1971-94 reveal warming trends after 1977 ranging from 0.06° to 0.12°C yr¹ in most of the Middle Mountain and Himalayan regions, while the Siwalik and Terai (southern plains) regions show warming trends less than 0.03°C yr¹. The subset of records (14 stations) extending back to the early 1960s suggests that the recent warming trends were preceded by similar widespread cooling trends. Distributions of seasonal and annual temperature trends show high rates of warming in the high-elevation regions of the country (Middle Mountains and Himalaya), …

Antarctic's Role Pursued In Global Climate Change, Paul Andrew Mayewski, I. Goodwin

Earth Science Faculty Scholarship

The impact of Antarctica on global climate change and the impact of global climate change on Antarctica are the focal points of a current series of expeditions there, and an international, interdisciplinary array of researchers met this past spring to go over the expeditions' progress. Advances were reported in describing the impact of the seasonal cycle, semiannual oscillation, and the El Niño-Southern Oscillation (ENSO) cycle on Antarctic accumulation in recent decades.

Difficulties still remain, however, in explaining fully the history and forcing of the Antarctic climate and the links between tropical forcing and high-latitude response. The difficulties arise largely because …

Spatial Variability Of Climate And Past Atmospheric Circulation Patterns From Central West Antarctic Glaciochemistry, David B. Reusch, Paul Andrew Mayewski, Sallie I. Whitlow, Iqbal I. Pittalawa, Mark S. Twickler

Earth Science Faculty Scholarship

Atmospheric circulation patterns and the spatial variability of atmospheric chemistry and moisture transport in central West Antarctica are investigated using new 40 year long (1954–1994 A.D.) glaciochemical and accumulation rate records developed from four firn cores from this region. The core sites lie on a 200 km traverse from 82° 22′ S, 119° 17′ W to 81° 22′ S, 107° 17′ W. The glaciochemical records represent the major ionic species present in Antarctic snow: Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃⁻, and SO₄²⁻. High spatial …

The Weddell Sea Region: An Important Precipitation Channel To The Interior Of The Antarctic Ice Sheet As Revealed By Glaciochemical Investigation Of Surface Snow Along The Longest Trans-Antarctic Route, Qin Dahe, Paul Andrew Mayewski, Ren Jiawen, Xiao Cunde, Sun Junying

Earth Science Faculty Scholarship

Glaciochemical analysis of surface snow samples, collected along a profile crossing the Antarctic ice sheet from the Larsen Ice Shelf, Antarctic Peninsula, via the Antarctic Plateau through South Pole, Vostok and Komsomolskaya to Mirny station (at the east margin of East Antarctica), shows that the Weddell Sea region is an important channel for air masses to the high plateau of the Antarctic ice sheet (>2000 m a.s.l.). This opinion is supported by the following. (1) The fluxes of sea-salt ions such as Na⁺, Mg²⁺ and Cl⁻ display a decreasing trend from the west to the …

Seasonal Variations Of Glaciochemical, Isotopic And Stratigraphic Properties In Siple Dome (Antarctica) Surface Snow, K. J. Kreutz, Paul Andrew Mayewski, M. S. Twickler, S. I. Whitlow, J. W.C. White, C. A. Shuman, C. F. Raymond, H. Conway, J. R. Mcconnell

Earth Science Faculty Scholarship

Six snow-pit records recovered from Siple Dome, West Antarctica, during 1994 are used to study seasonal variations in chemical (major ion and H2O2), isotopic (deuterium) and physical stratigraphic properties during the 1988-94 period. Comparison of dD measurements and satellite-derived brightness temperature for the Siple Dome area suggests that most seasonal dD maxima occur within ±4 weeks of each 1 January. Several other chemical species (H2O2, non-sea-salt (nss) SO42-, methanesulfonic acid and NO3-) show coeval peaks with dD, together providing an accurate method for identifying summer accumulation. Sea-salt-derived species generally peak during winter/spring, but episodic input is noted throughout some years. …

Climatological Significance Of Δ18O In Precipitation And Ice Cores: A Case Study At The Head Of The Ürütnqi River, Tien Shan, China, Hou Shugui, Qin Dahe, Paul Andrew Mayewski, Yang Qinzhao, Ren Jiawen, Li Zhongqin, Xiao Cunde

Earth Science Faculty Scholarship

Stable-oxygen-isotope ratios (δ¹⁸O) collected from the headwaters of the Ürümqi river, Tien Shan, China, were used to test the relationship between δ¹⁸O temporal relationship is found between δ¹⁸O monthly averages which remove synoptic-scale influences such as changes in condensation level, condensation temperature and moisture sources (Yao and others, 1996). Linear fits as high as 0.95‰°C^-1 for precipitation events and 1.23‰°C^-1 for monthly averages are found. Although the δ¹⁸O (∼2 km from the precipitation sampling site) decreased dramatically compared to the precipitation samples , the ice-core records of annually averaged δ …