Eastern Mineral Resources Team
Background geochemical surveys determine natural variations in elements both between geographic areas and among various geological materials within an area. This information is essential to accurately assess how natural and anthropogenic geochemical variations affect the environment, wildlife, and human health.
Regional geochemical studies using various soil layers, stream sediments, and lake sediments are being conducted with assistance from USDA Forest Service. The project is providing a comprehensive, multi-media data base on chemical variations in natural materials in and near the Forest. Concurrently, research is exploring the relationships between chemical composition of surficial materials and geologic variables such as types of bedrock, glacial deposits, and soils. Results will provide a rationale in which maximum use can be made of available geochemical information in order to streamline planning and conducting future geochemical surveys. (More on Chequamegon National Forest)
Additional research in the Chequamegon National Forest is measuring the geochemical impact of undisturbed mineral deposits on surficial materials. Mineral deposits are natural concentrations of numerous elements, some of potential environmental concern. Natural processes are capable of dispersing those elements into surrounding materials both by physical transport, such as in glacially transported materials, and by chemical dispersal in groundwater. It is important to determine the extent and intensity of natural dispersal, both to identify possible current environmental impacts and to assess potential impacts of future mining. Two deposits within the Forest are being studied. Both have been drilled extensively during mineral exploration, but are otherwise undisturbed. (More on studies of undisturbed mineral deposits)
Isle Royale, a pristine wilderness island in northern Lake Superior, is the site for studies of surficial geochemistry related to mercury distribution. In spite of lack of permanent human habitation and very limited past mining activity, mercury levels are high in some soils and biota on the island. Joint investigations are being conducted with scientists in the USGS Biological Resources Division to map the pattern of recent airborne mercury deposition, using lichens as natural air-quality monitors, and to determine if changes in airborne deposition can be related to variations in the mercury content of soils. (More on mercury on Isle Royale)
In support of the Geochemical Backgrounds and Baselines project in Northern Wisconsin, we are working to put together an updated database of National Uranium Resource Evaluation (NURE) data. There are between quadrangle biases, especially in the NURE stream sediment data, that become apparent when the data is re-analyzed using current laboratory analytical techniques. NURE samples are archived by the USGS in Denver, CO and are available for re-analysis. This re-analysis of the data has enabled us to perform a mathematical adjustment of the original NURE stream sediment data, thus helping to reduce the between quadrangle bias, and improve the quality of the data for over 20 elements. (More on NURE data adjustment) (pdf file, 134KB)
Other project activities in the Upper Midwest are described in two Information Handouts:
U.S. Geological Survey's Mineral Resources Program Activities in the Upper Midwest (April 1999)
Potential for New Nickel-Copper Sulfide Deposits in the Lake Superior Region (1997)
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U.S. Geological Survey
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Page Last Modified: 12-Jun-2008@14:20
