Digital Base for Geological Mapping within the Northern South Kawishiwi Intrusion: Lake and St. Louis Counties, Northeastern Minnesota

Abstract

This map depicts the outcome of several hundred hours of digitizing contour lines and associated topographic map data (lakes, streams, roads, trails) as well as updating a three-dimensional database of drill hole information and scattered surface sample geochemical analyses for the northern portion of the South Kawishiwi Intrusion. The data was digitized in three-dimensions, and was used to generate the 3D image of the surface topography that forms the background of the map sheet. As well, all of the data has been incorporated into a detailed GIS basemap of the area. The purpose of this work is two-fold: (1) to visually comprehend the geomorphology of this area (which is in the scoured bedrock terrane of northeastern Minnesota) as a tool in understanding the bedrock and surficial geology, and (2) to provide a visual impetus for funding a large geological mapping project in this economically significant (Cu-Ni-PGE mineral potential) and environmentally sensitive (BWCAW) area. Such a project would need financial support from both the University of Minnesota Duluth's Natural Resources Research Institute and from companies in the Minerals Industry that have active Cu-Ni-PGE mineral exploration programs situated within the boundaries of this map sheet (Duluth Metals Limited, Franconia Minerals, Encampment Resources). These active mineral exploration activities are being driven by greatly increased metal prices as a result of global economic expansion. Previous mineral exploration programs within the boundaries of this map sheet has included approximately 607 exploration holes totaling over 90 miles of core (296 kilometers) that was drilled between the years 1951 - 2006. Integration of geologic data from these historic exploration programs into a conservative geological resource estimate of contained copper, nickel, platinum, palladium, and gold indicates that at today's metal prices, over $500 billion dollars of these metals (which includes an estimated 50 million ounces of palladium, 25 million ounces of platinum, and 10 million ounces of gold) is hosted by the South Kawishiwi Intrusion within this map sheet (Peterson, unpublished data). The economic significance of these geological resources, along with the possible extraction of these metals in the future, is driving the author's desire to complete a new geological map of a large portion of this area. Published geological maps of portions of this sheet are given in the "INDEX TO MAPPING". Review of this figure highlights the need for a new mapping campaign, namely that the bulk of this area has only been mapped at small scales (1:31,680 and 1:48,000 scales) thirty to forty years ago, prior to the great advances in our knowledge of the geology, geophysical characteristics (Fig. 1), and mineralization in the Duluth Complex over the past twenty years.