Remote sensing and geochemical investigations of selected surface processes in Egypt and Missouri

This thesis consists of three studies of surface processes on Earth: 1. Age and isotopic constraints of pluvial episodes in the Western Desert of Egypt. North Africa has undergone drastic climatic change over the past several hundred thousand years. Timing of humid intervals called pluvials was investigated by uranium-series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert, Egypt. Stable oxygen isotopes of the travertines were used in equilibrium oxygen isotope fractionation calculations indicating the Kurkur travertines have {dollar}deltasp{lcub}18{rcub}{dollar}O values similar to ancient Western Desert groundwaters ({dollar}{lcub}sim{rcub}{lcub}-{rcub}11perthous{dollar}). The ages of the of the travertines correspond to times of monsoonal maxima, eustatic sea level high stands and interglacial maxima. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during periods of enhanced northern summer insolation.; 2. Identification of soil moisture as an environmental risk factor for filariasis in Egypt. Bancroftian filariasis is a deforming illness transmitted by mosquitoes (Culex. pipiens) and caused by the parasite Wuchereria bancrofti (WHO technical report 821; Neva and Brown, 1994). Environmental variables, such as humidity, play an important role in the transmission cycle of filariasis. Landsat Thematic Mapper data were used to model the surface soil moisture conditions of the southern Nile Delta region of Egypt as a proxy for environmental humidity. Filariasis infection rates were found to be negligible for areas with low surface soil moisture availability ({dollar}>{dollar}20%). Variable infection rates were observed for regions with higher surface soil moisture content, possibly due to anthropogenic influences such as insect control and the use of anti-filarial drugs.; 3. Monitoring of Pb aerosol fallout in the vicinity of the Glover smelter, Southeastern Missouri. Pb ore smelting in Southeastern Missouri is a point source for heavy metal particulates that are dispersed over a wide region. Pb ratios of the ores are distinct from local bedrock and background atmospheric Pb. A feasibility study to determine the usefulness of Sector Field ICP-MS analysis of Pb isotopes and heavy metal concentrations of leaves sampled at increasing distance from the smelter was initiated. The goal was to develop an inexpensive and relatively simple means of mapping the impact of heavy metals on the ecosystem surrounding the smelter.