Eastern Mineral and Environmental Resources Science Center
The geochemical landscape of the Chequamegon National Forest is being defined though studies of various soil horizons and sediments from stream-beds and lake-bottoms. Studies of soils are being conducted in cooperation with the USDA Forest Service who are providing samples collected and described during previous soil characterization studies. Additional samples have been collected as needed to complete regional coverage and for specialized studies. Analyses of 43 elements is being performed on all samples. About 400 samples of stream-bed sediments have been similarly analyzed. The samples were originally collected and analyzed during the National Uranium Resource Evaluation program in the late 1970's and have since been archived at USGS facilities in Denver, Colorado. The new analyses take advantage of modern analytical methods with improved accuracy and detection limits.
Geochemical patterns are being interpreted using a geographic information system (GIS) approach in which results of the geochemical surveys can be efficiently displayed in various map formats and compared with numerous other GIS data layers. The interpretation of geochemical results is being done in cooperation with the Great Lakes Ecological Assessment, a multi-agency project spear-headed by USDA Forest Service. The Great Lakes Assessment has assembled nearly 200 GIS layers characterizing the physical, biological, and cultural aspects of the region. GIS analyses will allow rapid determination of interrelationships of surficial geochemistry and numerous other characteristics of the region. The geochemical results will provide important new layers to the GIS for the Chequamegon Forest region.
Of equal importance is the application of a GIS approach to quantify links between various geological variables and surficial geochemistry. An expected outcome of this research is development of sampling and interpretive techniques for efficient and accurate geochemical baseline determinations that use existing maps of surficial and bedrock geology and soil types to design sampling programs that will provide accurate geochemical characterization of a region with a minimum of samples and analyses. These techniques will allow future surveys to be conducted with maximum efficiency.
|Rob Barber-DeLach and Bill Cannon, USGS, using gravity core sampler to sample lake bottom sediments on Bear Skull Lake, Wisconsin.|
|Laurel Woodruff and Bill Cannon, USGS, sample bottom sediments from Perch Lake, Chequamegon National Forest, Wisconsin.|
|Mineral Resources Program||National Minerals Information / Geology, Minerals, Energy and Geophysics|
|Alaska / Crustal Geophysics and Geochemistry / Central Mineral and Environmental Resources / Spatial Data|