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This collection contains miscellaneous maps created by faculty and/or staff at the Natural Resources Research Institute (NRRI). At this point we are unaware of any reports or other documents that these maps belong with, but we may find related materials in the future.

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Now showing 1 - 9 of 9
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    Shaded Relief Map of the Basal Contact Surface of the South Kawishiwi Intrusion Duluth Complex, Northeastern Minnesota
    (University of Minnesota Duluth, 2002-03) Peterson, Dean M
    This map depicts a 3-dimensional model of the interpreted shape of the bottom of the western margin of the South Kawishiwi Intrusion (SKI) that is based on ~800 drill hole piercing points into footwall rocks and geophysical data (gravity and aeromagnetic). Severson (1994) defined the igneous stratigraphy of the SKI in the map area based on drill core logging, and the vast majority of all geological information used by the author in the development of this map is taken from that work. Compilation and modeling of geochemical data for all of the mineralized zones within the Partridge River and South Kawishiwi intrusions has been presented by Peterson (1997), and is the source for much of the drill hole assay data within the map area. New interpretations and descriptions of the geology and mineral potential of the whole Duluth Complex have been recently completed (Miller et al., 2001; 2002), and readers interested in the geology of this map area should refer to all these works. A simplified 3-dimensional bedrock geological map of the rocks adjacent to, within, and beneath the western margin of the South Kawishiwi Intrusion is presented in Figure 1. Cross sections of the topographic expression of the basal contact of the SKI are presented in Figure 2. The 3-D model has been instrumental in the development of new ideas on the styles and origin of the Cu- Ni-PGE mineralization within the SKI. Integration of regional geological, geophysical, and geochemical features with the 3-D model has led to new ideas on possible feeder channels for magmas of the northern SKI. The interpreted master magmatic feeder channel of the northern SKI is fed from the central Mid- Continent Rift through the Bald Eagle Intrusion gravity high, into a dike-like body of troctolitic rocks (herein termed the Bald Eagle Trough) cutting older Anorthositic Series rocks (Fig. 3). Integration of the concept of a magmatic feeder channel with assays has led to the development of conceptual models for the formation of the Spruce Road (Peterson, 2002) and Maturi (Peterson, 2001) deposit areas. Early magmas that formed the Spruce Road deposit were deflected to the north by a pillar of older Anorthositic Series rocks that is located at depth within the northern portion of the SKI (Fig. 1). Moreover, PGE-enriched Cu-Ni mineralization of the Maturi Extension deposit is located beneath the pillar, and a conceptual model for the formation of this deposit area is presented in Peterson (2001). 1) Open - (early) vertically extensive (> 450 meters) mineralization with generally low to moderate Cu-Ni grade and low Au+PGE grades; and 2) Confined - (later) vertically restricted (< 150 meters) mineralization with moderate to high Cu-Ni grades and moderate to very high (locally) Au+PGE grades; and 3) Cloud Zone - (latest) Cu-Ni-PGE mineralization seemingly unrelated to the basal contact. Regional geologic and crosscutting relationships (Fig. 3) indicate that the Open-style mineralization preceded the Confined-style.
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    Bedrock Geology, Sample Location, and Property Position Maps of the West Birch Lake Area, South Kawishiwi Intrusion, Duluth Complex, Lake and St. Louis Counties, Northeastern Minnesota
    (University of Minnesota Duluth, 2002-04) Peterson, Dean M; Marma, John; Brown, Philip
    This map (NRRI/MAP-2002/02) is the outcome of eight field days mapping and sampling in the area by the senior author. The initial impetus for this mapping was to try to define Duluth Complex induced contact-metamorphic zonation in the footwall Giants Range batholith, and to relate this to Cu-rich mineralization in these rocks. Research into footwall Cu-rich mineralization continues, and will be published in the future. However, the discovery of large expanses of Cu-Ni mineralized rock in the basal zone of the South Kawishiwi, in an essentially unmapped area, lead to this preliminary map (Figure 1). The geologic map represents the initial interpretaton of the bedrock geology of the basal zone of the South Kawishiwi Intrusion, based on mapped outcrops, subcrops, and glacial materials (float). In addition, geologic units intersected in drill holes have been projected updip to the surface. The faults depicted on the map are interpreted from aeromagnetic data, steepening of the dip of the basal contact of the Duluth Complex, and topographic lineaments. The location and simplified regional geology encompassing the map area is depicted in Figure 4. The lithologic legend of the geology map is simplified into the intrusive stratigraphy of the South Kawishiwi Intrusion first defined by Severson (1994). Readers interested in detailed descriptions of the regional South Kawishiwi Intrusion stratigraphy are referred to that work. Cu-Ni-PGE mineralization is largely confined to the basal stratigraphic units of the intrusion (units BAN, BH, and U3), and on the ground is largely represented by knob-like outcrops, and large expanses of rusty, gossaneous boulder fields (subcrops). Old test pit dumps (circa 1890 ?) into the Biwabik Iron Formation are common in the southern portion of the map, and occur in areas of anomalous magnetic field properties. Seventy-five rock samples (Figure 2) were collected in the area (described in Table 1), and Dr. Philip Brown and John Marma (Department of Geology, University of Wisconsin - Madison) provided the funding for the base- and precious-metal analyses of twenty of these samples (presented in Table 2). Check assays for anomalous samples were analyzed by ALS Chemex labs from the original pulps and rejects (Table 2). Assay data for the majority of the drill holes in the map area have been compiled by Peterson (1997), which includes > 60,000 geochemical analyses for drill holes throughout the Duluth Complex. The smaller-scale property position map (Figure 3) depicts the current mineral lease holders in the area, and should only be viewed as a "snapshot" of the mineral land positions at the date of this map. Detailed geologic mapping in the area, including additional geochemical analyses, has been approved from the Permanent University Trust Fund, and will be completed during the 2002 field season.
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    Bedrock Geology Map of the Nickel Lake Macrodike and Adjacent Areas: Lake County, Northeastern Minnesota
    (University of Minnesota Duluth, 2006-11) Peterson, Dean M; Albers, Paul B; White, Chris R
    This map is the first of what is hoped (contingent on funding) to be a series of new detailed bedrock geology maps of the marginal zone of the South Kawishiwi Intrusion by the University of Minnesota Duluth's Natural Resources Research Institute (see Peterson, 2006). Such mapping will form the basis for continued exploration for Cu-Ni-PGE mineralization as well create the geologic base upon which environmental review associated with exploitation of such mineralization can be built. Recent detailed mapping at a scale of 1:5,000 by the authors was conducted west and south of the Boundary Waters Canoe Area Wilderness (BWCAW). Nearly 1,000 outcrops along approximately 100 kilometers of field traverses were examined to identify and confirm the internal lithologic variability, contact relationships, and structure of the Nickel Lake Macrodike between the BWCAW and Omaday Lake. The authors wish to acknowledge Dr. Paul Weiblen (emeritus professor of geology at the University of Minnesota) for his keen insight of the geology of the area and Dr. George Hudak and undergraduate student Jeremiah Gowey of the University of Wisconsin Oshkosh for assistance in mapping outcrops around and south of Omaday Lake. Additional reconnaissance mapping in early November by the senior author was conducted to field check compiled outcrop locations depicted on the 1957 INCO map of the Spruce Road Deposit and the 1968 Hanna Mining map of the South Filson Creek Deposit (both of which are publically available in the DNR archive at Hibbing, Minnesota). The reconnaissance mapping confirmed the location of gossaneous Cu-Ni bearing INCO outcrops and reconfirmed the outstanding field mapping of all types of Duluth Complex rocks by Hanna Mining Company geologists of the late 1960s (see figure of "Sources of Information"). This map has been built upon (in the areas surrounding depicted outcrops and historic drill holes) the 1966 map of the Gabbro Lake 15' quadrangle by Green et al. (Minnesota Geological Survey Miscellaneous Map M-2), which because of its quality has been the geologic foundation for this area for 40 years. The reader of this map should compare the author's interpretation of the bedrock geology to that depicted on M-2, which will undoubtedly highlight the need for continued detailed mapping of the marginal zone of the South Kawishiwi Intrusion (which was not the purpose of map M-2), especially in light of the greatly increased interest in the potential for exploiting the vast resources of Cu-Ni-PGE mineralization enclosed within these rocks. The Nickel Lake Macrodike is lithologically and structurally related to the South Kawishiwi Intrusion and the known Cu-Ni-PGE deposits of Birch Lake, Maturi, Maturi Extension, Spruce Road, and South Filson Creek. The citation for this map includes the caveat "Version 1", which points out the fact that the authors believe that more detailed geologic mapping and analytical studies (no petrography or geochemical analyses of recently collected samples has been completed) are needed to truly understand what the bedrock geology enclosed within the boundaries of this map sheet (and the area to the west-southwest) really is (ie. we've only begun to scratch the surface). This map and all associated GIS data (in ArcView 3.2 format) can be obtained online at
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    Digital Base for Geological Mapping within the Northern South Kawishiwi Intrusion: Lake and St. Louis Counties, Northeastern Minnesota
    (University of Minnesota Duluth, 2006-07) Peterson, Dean M
    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.
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    Bedrock Geologic Map of the Duluth Complex in the Northern South Kawishiwi Intrusion and Surrounding Area, Lake and St. Louis Counties, Minnesota
    (University of Minnesota Duluth, 2008-05) Peterson, Dean M
    This map is the result of numerous investigations by the author and many others over the last 8 years of the South Kawishiwi intrusion (SKI) and it's contained Cu-Ni-PGE mineralization. Detailed geological mapping evolved from a study of the Nickel Lake Macrodike (NLM) into a comprehensive geologic mapping and compilation project (104,000 acres) to answer some of the fundamental questions on the origin of the extensive known and undiscovered Cu-Ni-PGE mineralization in the northern portion of the SKI. Such an increase in scope is needed due to the economic significance of the published resource estimates (>$146 billion in contained metal) from this area. To date, nearly 15,000 outcrops, 1,400 structural measurements, geology and geochemistry from 773 drill holes totaling over 845,000 feet of core, and 12,500,000 meters of elevated contour lines (see Digital Topography image below) have been integrated into the comprehensive GIS database. The map units of the SKI depicted on this map sheet differ from previous maps from the area, in that the author has consulted with numerous company geologists and defined map units based on what industry geologists use to define rock masses encountered in drill core. This new map includes geology from each of the major lithologic units in the area, namely the Late Archean Giants Range batholith, the Paleoproterozoic Biwabik Iron and Virginia Formations, and the Anorthositic Series, Bald Eagle Intrusion, SKI, and the NLM of the Mesoproterozoic Duluth Complex. There are only a few faults depicted on the map, and literally hundreds of kilometers of linear topographic features that remain to be investigated in detail (see Digital Topography image below). However, little obvious offset of rock units have been observed along these features where investigated in detail, thus the author has purposely not drawn many faults on the map. One main new insight of this recently completed compilation is the recognition that the northeastern extent of the SKI is not a shallowly dipping sill but rather a southwest trending, inclined funnel-like body. Such an interpretation leads to the conclusion that the eastern contact of the SKI, which previously was interpreted as the top of the intrusion, is a basal contact, and thus has great potential for hosting Cu-Ni-PGE mineralization at its base. Understanding the origin of mineralized zones is the goal of all economic geologists, and in magmatic ore systems like the SKI, one must try to imagine the magmatic processes that culminated in the formation of the ores and surrounding rocks, i.e. how did the SKI form? Did the magmas intrude as crystal-laden slurries? Are the "Open" and "Confined" styles of mineralization defined by Peterson (2001) true mappable units? Such thoughts are the basis upon which the author began the quest to complete this map sheet. The author has inserted a number of inset maps and figures for the reader to review and ponder about the possible types of magmatic prosesses that occurred in the area (now depicted on this map sheet) 1.1 billion years ago. It is hoped that careful review of the bedrock geologic map and inset figures will give the reader and user of the map new geologic insight and ideas for future mineral exploration programs and scientific study.
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    Mesabi Hard Rock Usage in Minnesota
    (University of Minnesota Duluth, 2006) Patelke, Marsha Meinders
    Example projects represent a subset of Mesabi Hard Rock usage statewide.
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    Bedrock Geology Map and Cu-Ni Mineralization Data for the Basal Contact of the Duluth Complex West of Birch Lake, St. Louis and Lake Countiues, Northeastern Minnesota
    (University of Minnesota Duluth, 2004) Peterson, Dean M; Patelke, Richard L; Severson, Mark J
    This map is the outcome of eight days of field mapping by Dean M. Peterson in 2001 (Peterson, 2002e), and 6 days of mapping by the authors in 2002. The discovery of large (hundreds of meters long) gossanous expanses of Cu-Ni mineralized rock in the basal zone of the South Kawishiwi intrusion (SKI) in 2001 (in a historically under-mapped area) lead to the acquisition of funds to complete the subsequent detailed geological mapping that resulted in the publication of this map sheet. The mapping was completed at a scale of 1:3,000 and was concentrated within the Cu-Ni-PGE mineralized horizon immediately east of the basal contact of the Duluth Complex. Three mapping traverses were completed to the west into the footwall Neoarchean Giants Range batholith, and to the east into the unmineralized rocks of the SKI stratigraphically overlying the mineralized zone. The information generated from the detailed geological mapping was integrated with previous work by Phinney (1967), Miller et al. (2001), and Miller et al. (2002c), outside of the corridors of detailed mapping during the final compilation of this geologic map (see Fig. 1). In addition, geologic units intersected in the scattered drill holes in the area (see Severson, 1994) have been projected updip to the surface. The faults depicted on the map are interpreted from analysis of aeromagnetic data, steepening of the dip of the basal contact of the Duluth Complex (Figs. 2 and 3), and topographic lineaments. Digital data will be available online at in the fall of 2004.
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    Bedrock Geology and Lode Gold Prospect Data Map of the Mud Creek Road Area, Northern St. Louis County, Minnesota
    (University of Minnesota Duluth, 2004) Peterson, Dean M; Patelke, Richard L
    Gold mineralization in northeastern Minnesota occurs in numerous prospects east of Lake Vermilion in rocks of the Bass Lake sequence (Peterson and Jirsa, 1999) of the Neoarchean Wawa Subprovince of the Canadian Shield. This zone of abundant gold mineralization is bounded to the south by the Mud Creek shear zone and to the north by the Vermilion fault (Fig. 1). The main access to these prospects is along the Mud Creek road (County Road 38). A brief period of mineral exploration for lode-gold deposits in this immediate area of the Vermilion district occurred in the mid 1980s to early 1990s. These programs typically consisted of grid-based geologic mapping, bedrock sampling, ground geophysics, and the completion of soil geochemical surveys. Personal conversations with many of the people involved in gold exploration programs in the area, and compilation of all exploration data from the district as a whole by Peterson (2001), has led to the conclusion that interpretation of linear structural elements exposed in outcrops were typically not used in designing exploratory drilling plans in the map area. Therefore, many of the prospects discovered on the surface as a result of these exploration programs remain untested by drilling. The goal of this project was to try to determine the downdip orientation of specific gold mineralized zones discovered in these previous exploration programs, and therefore, encourage new gold exploration in the area. Brief descriptions of the techniques used in the project are described below. Detailed geologic outcrop maps (at scales ranging from 1:1,000 to 1:3,000) were completed for a number of the gold prospects located in the field area. The mapping was focused on structural (shear zones, lineations, intersecting foliations and small-scale folds), geological (contact relationships, competence contrasts), geochemical (gold assays, trace element characteristics), and alteration (Fe-bearing carbonate, sericite, pyrite, silicification) features within and around areas of gold mineralized exposures.
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    Archean Geology of the Minnesota River Valley Sacred Heart to Morton Geology
    (University of Minnesota Duluth, 2016-12) Grant, James A; Oreskovich, Julie A