Geology and Mineral Deposits of the Keweenaw Peninsula and Vicinity, Michigan

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Frequently anticipated questions:


What does this data set describe?

Title:
Geology and Mineral Deposits of the Keweenaw Peninsula and Vicinity, Michigan
Abstract:
The area of this data set includes the classic geology and mineral deposits of the Keweenaw Peninsula, renowned for the occurrence of great volumes of Middle Proterozoic flood basalts and the world's largest concentration of native copper. Native copper was mined there continuously from the 1840's to the 1960's. For the earlier part of that period the Keweenawan native copper district was the principal source of copper for the United States.
  1. How might this data set be cited?
    Cannon, William F., McRae, Michele E., and Nicholson, Suzanne W., 1999, Geology and Mineral Deposits of the Keweenaw Peninsula and Vicinity, Michigan: U.S. Geological Survey Open-File Report 99-0149.

    Online Links:

    Other_Citation_Details:
    ArcView project and coverages (3MB) and ARC/INFO export .e00 files (3MB).
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.0
    East_Bounding_Coordinate: -87.5
    North_Bounding_Coordinate: 47.5
    South_Bounding_Coordinate: 46.4
  3. What does it look like?
    http://pubs.usgs.gov/of/1999/of99-149/index.pdf (PDF)
    A PDF representation of the geology and mineral deposits of the Keweenaw Peninsula and vicinity, Michigan
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 1999
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: map
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a vector data set. It contains the following vector data types (SDTS terminology):
      • Entity point
      • Complete chain
      • GT-polygon composed of chains
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -87
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest unknown
      Ordinates (y-coordinates) are specified to the nearest unknown
      Planar coordinates are specified in meters
      The horizontal datum used is NAD27.
      The ellipsoid used is CLARKE 1866.
      The semi-major axis of the ellipsoid used is 6378206.
      The flattening of the ellipsoid used is 1/294.98.
  7. How does the data set describe geographic features?
    GEOLOGY.PAT
    Geologic map units (Source: OFR-99-0149)
    SYMBOL
    Abbreviation of named unit (Source: OFR-99-0149, Attribute UNIT_NAME)
    ValueDefinition
    PzuPaleozoic undivided
    YjJacobsville Sandstone
    YfFreda Sandstone
    YfaFreda Sandstone, andesite member
    YnNonesuch Formation
    YcCopper Harbor Conglomerate
    YcbCopper Harbor Conglomerate, Basalt Member
    YiIndiana felsite
    YfiIntrusive Rhyolite
    YbMt. Bohemia stock
    YplPortage Lake Volcanics undivided
    YplfRhyolite: Portage Lake Volcanics
    YplgGreenstone Flow: Portage Lake Volcanics
    YplkKearsarge Flow: Portage Lake Volcanics
    YplgrGratiot Flow: Portage Lake Volcanics
    YplsScales Creek Flow: Portage Lake Volcanics
    YplcCopper City Flow: Portage Lake Volcanics
    YplbBohemia Conglomerate: Portage Lake Volcanics
    YdDiabase dikes
    YpuPowder Miss Group undivided
    YsSiemens Creek Volcanics
    XmMichigamme Formation
    WgrGranitic gneiss
    SUPERGROUP
    Map unit supergroup (Source: OFR-99-0149)
    ValueDefinition
    Marquette Range 
    Keweenawan 
    (blank) 
    GROUP
    Map Unit Group (Source: OFR-99-0149)
    ValueDefinition
    Baraga 
    Bergland 
    Oronto 
    Powder Mill 
    (blank) 
    ERA
    Geologic time scale era (Source: OFR-99-0149)
    ValueDefinition
    Proterozoic 
    Paleozoic 
    Archean 
    PERIOD
    Geological Time Scale Period (Source: OFR-99-0149)
    ValueDefinition
    undividedNo definite period
    Late Archean 
    Early Proterozoic 
    Middle Proterozoic 
    RK_TYPE
    Primary rock type of named unit (Source: OFR-99-0149)
    ValueDefinition
    Sedimentary 
    Metamorphic 
    Intrusive 
    Extrusive 
    SUBUNIT_NAME
    Subdivision within geologic unit. Unit_name given as Domain definition.. (Source: OFR-99-0149)
    ValueDefinition
    graywackeMichigamme Unit
    Lake Shore TrapsCopper Harbor Conglomerate Unit
    Bear Lake AndesiteFreda Sandstone Unit
    Bohemia ConglomeratePortage Lake Volcanics member
    Copper City FlowPortage Lake Volcanics member
    felsitePortage Lake Volcanics member
    Greenstone flowPortage Lake Volcanics member
    Gratiot FlowPortage Lake Volcanics member
    Kearsarge flowPortage Lake Volcanics member
    Scales Creek FlowPortage Lake Volcanics member
    (blank)No Subunit_name
    AGE
    Age of rock formation in Millions of years (Ma) (Source: OFR-99-0149)
    ValueDefinition
    (blank)Age unknown
    Range of values
    Minimum:1086
    Maximum:2750
    Units:millions of years ago
    Resolution:1
    MAJOR_SUBTYPE
    Further subdivision of RK_TYPE (Source: OFR-99-0149)
    ValueDefinition
    Carbonate 
    Conglomerate 
    Felsic 
    Intermediate 
    Mafic 
    Metasedimentary 
    Mudstone 
    Sandstone 
    gneiss 
    MAJOR_LITHOLOGY
    Predominant lithology of RK_TYPE (Source: OFR-99-0146)
    ValueDefinition
    andesite 
    basalt 
    black shale 
    conglomerate 
    diabase 
    felsite 
    granitic gneiss 
    limestone 
    metagraywacke 
    rhyolite 
    MINOR1_RKTYPE
    Other rock type within named unit (Source: OFR-99-0149)
    ValueDefinition
    Extrusive 
    Intrusive 
    Metamorphic 
    Sedimentary 
    (blank) 
    MINOR1_SUBTYPE
    Further subdivision of MINOR1_RKTYPE (Source: OFR-99-0149)
    ValueDefinition
    Amphibolite 
    Carbonate 
    Conglomerate 
    Intermediate 
    Metasedimentary 
    Mudstone 
    Sandstone 
    (blank) 
    MINOR1_LITHOLOGY
    Predominant lithology of MINOR1_RKTYPE (Source: OFR-99-0149)
    ValueDefinition
    amphibolite 
    andesite 
    arkose 
    conglomerate 
    diorite 
    dolomite 
    sandstone 
    siltstone 
    slate 
    (blank) 
    MINOR2_RKTYPE
    Other rock type within named unit (Source: OFR-99-0149)
    ValueDefinition
    Extrusive 
    Intrusive 
    Sedimentary 
    (blank) 
    MINOR2_SUBTYPE
    Further subdivision of MINOR2_RKTYPE (Source: OFR-99-0149)
    ValueDefinition
    Felsic 
    Mudstone 
    Sandstone 
    (blank) 
    MINOR2_LITHOLOGY
    Predominant lithology of MINOR2_RKTYPE (Source: OFR-99-0149)
    ValueDefinition
    granite 
    rhyolite 
    sandstone 
    siltstone 
    (blank) 
    PROVINCE_ORIGIN
    Province of origin (Source: OFR-99-0149)
    ValueDefinition
    Interior platform 
    Midcontinent rift 
    Penokean 
    Superior 
    SUBPROV/TERRANE
    Subprovince/terrane of origin (Source: OFR-99-0149)
    ValueDefinition
    Fold and thrust belt 
    Wawa 
    central horst 
    flanking basin 
    (blank) 
    PROVINCE_AGE
    Age of province of origin (Source: OFR-99-0149)
    ValueDefinition
    Early Proterozoic 
    Late Archean 
    Middle Proterozoic 
    Paleozoic 
    REWORKING_PROV, REWORKING_SUBPRO and REWORKING_AGE
    Province of reworking, Subprovince of reworking, and Age of reworking (Source: OFR-99-0149)
    ValueDefinition
    Penokean, Fold and thrust belt, Early Proterozoic 
    (blank) 
    ENV_OF_FORMATION
    Environment of formation (Source: OFR-99-0149)
    ValueDefinition
    andesite dome 
    dike 
    felsic dome 
    fluvial 
    fluvial, lacustrine 
    interflow conglomerate 
    lacustrine 
    marine 
    shallow marine 
    subaerial flood basalt 
    undetermined 
    TECTONIC_SETTING
    Tectonic setting of rock unit (Source: OFR-99-0149)
    ValueDefinition
    Post-rife thermal basin 
    continental rift basin 
    foreland basin 
    stable craton 
    undetermined 
    LITH_ASSEMBLAGE
    Lithologic assemblage (Source: OFR_99-0149)
    ValueDefinition
    black shale 
    carbonate, clastic sediments 
    coarse clastic sediments 
    coarse clastic sediments, metamorphosed 
    felsic intrusive 
    felsic volcanics 
    gneiss complex 
    intermediate volcanics 
    mafic dikes 
    mafic volcanics 
    ROADS, STREETS, & TRAILS.AAT
    location of roads, streets, and trails (Source: OFR_99-0149)
    TYPE
    Type of road, street, or trail (Source: OFR-99-0149)
    ValueDefinition
    Primary Roads 
    Secondary Roads 
    Light Duty Roads 
    Other Street 
    Trails 
    STRUCTURAL FEATURES.AAT
    Linear structural features (Source: OFR-99-0149)
    TYPE
    Type of structural feature (Source: OFR-99-0149)
    ValueDefinition
    Limestone Mtn. Structural Zone 
    syncline 
    ATTITUDE.PAT
    Orientation of Units (Source: OFR-99-0149)
    TYPE
    Type of orientation (Source: OFR-99-0146)
    ValueDefinition
    Strike & Dip of Bedding 
    strike & dip of foliation or cleavage 
    strike & dip of overturned bedding 
    strike of vertical bed 
    STRIKE
    Strike of bedding (Source: OFR_99-0149)
    Range of values
    Minimum:1
    Maximum:342
    Units:degrees
    Resolution:1
    DIP
    Dip of bedding (Source: OFR-99-0149)
    Range of values
    Minimum:5
    Maximum:90
    Units:degrees
    Resolution:1
    ANGLE
    An rotation angle for use with ArcView which allows the user to correctly orient the symbols (Source: OFR-99-0149)
    Range of values
    Minimum:0
    Maximum:358
    Units:degrees
    Resolution:1
    Entity_and_Attribute_Overview:
    ARC/INFO .e00 files:
    
    ATTITUDE - Orientation of bedding features (e.g., strike and dip)
    BURIED - Features concealed by Jacobsville Sandstone
    CGL - Interflow conglomerates
    CHALC - Chalcocite bodies
    COORD - A 15X15 minute geographic latitude/longitude locator grid
    FISSURE - Fissure veins
    GEOLOGY - Geologic units and faults
    LAKES - Lakes
    LODES - Native copper lodes
    MAG - Distinct aeromagnetic trends
    MINES - Mine shafts in the native copper district
    OUTCROPS - Locations of outcrops
    RIVERS - Rivers and streams
    ROADS - Roads
    STRUCTUR - Major structural features (other than faults)
    WETLANDS - Wetlands, marshes, bogs, etc.
    XSECTION - Cross section lines
    
    Entity_and_Attribute_Detail_Citation: More information can be found in the README

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • William F. Cannon
    • Michele E. McRae
    • Suzanne W. Nicholson
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Bill Cannon
    MS 954, U.S. Geological Survey
    Reston, Virginia
    USA

    (703) 648-7345 (voice)
    wcannon@usgs.gov

Why was the data set created?

This database is intended to summarize and update a wealth of very detailed geologic maps of the region. The related hardcopy publication, Geologic Map of the Keweenaw Peninsula and Adjacent Area, Michigan (Cannon and Nicholson), is part of a set of maps portraying the regional geology of the Midcontinent rift on the south shore of Lake Superior.
The geology and mineral deposits of the district have been painstakingly studied for many years. Milestones in the studies were the extensive report of Butler and Burbank (1929) and the detailed geologic maps produced by the USGS in the 1950's. The latter were aided greatly by the Calumet and Hecla Copper Company which provided USGS geologists with a wealth of exploration and production data that allowed construction of detailed 1:24,000 scale maps for the entire peninsula. Those maps are the principal source of information used to compile this data set. We have attempted to preserve as much detail as possible at 1:100,000 scale. For rocks northwest of the Keweenaw fault we have made few changes to previously mapped geology. New data is limited to deposits of chalcocite and native copper discovered since the previous mapping in the 1950's, to a more detailed study of rhyolite bodies, and to radiometric age determinations. For areas southeast of the Keweenaw fault, new geophysical data and drill holes allow some new inferences about the geology of volcanic rocks covered by a thin veneer of Jacobsville Sandstone.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    (process 1 of 18)
    The point features in the coverage ATTITUDE represent orientation of bedding or bedding features. However, they are not the actual geographic location of measurements. Rather, symbols thought to adequately represent the trend of geologic units were selected and generalized from larger scale geologic maps (1:24,000 and 1:62,500) and compiled on 1:100,000 scale mylar overlay. These were digitized using GSMAP software and converted to ARC/INFO format. Line features and duplicate points were deleted, the names of P1 and P2 changed to STRIKE and DIP, respectively, and the field ANGLE added and populated.
    (process 2 of 18)
    The coverage BURIED are previously unpublished features covered by the Jacobsville Sandstone. They were mapped as a result of new interpretations of aeromagnetic and gravity data and compiled on 1:100,000 scale mylar overlays. They were digitized using GSMAP software and converted to ARC/INFO format. Line topology was constructed and the more descriptive attribute TYPE added.
    (process 3 of 18)
    The arcs in the coverage CGL represent conglomerates interbedded with flows of the Portage Lake Volcanics. They were digitized from 1:24,000 scale geologic maps using GSMAP software. GSMAP files were converted to ARC/INFO format for editing, building topology, and populating attribute tables.
    (process 4 of 18)
    The polygons in the coverage CHALC represent known chalcocite bodies. They were compiled on 1:100,000 scale mylar base from detailed unpublished maps from the Michcan Copper Company, Ltd. and then digitized in GSMAP. GSMAP files were converted to ARC/INFO for editing, building topology, and populating attribute tables.
    (process 5 of 18)
    The coverage CORD is a 15 minute by 15 minute geographic coordinate grid which was created using the FISHNET option of the GENERATE command in ARC/INFO. It was then projected to the UTM coordinate system and clipped to match the extent of the rest of the Keweenaw data set.
    (process 6 of 18)
    The coverage FISSURE were digitized from 1:24,000 scale geologic maps using GSMAP software and converted to ARC/INFO format. In ARC/INFO, topology was built, and attribute fields added and populated.
    (process 7 of 18)
    The coverage GEOLOGY were digitized from 1:24,000 and 1:62,500 scale maps using GSMAP software and converted to ARC/INFO format. Imported geologic and fault lines were adjusted to match shorelines from the USGS 1:100,000 scale Digital Line Graphs (DLG's). Any unclosed polygons or dangling arcs were then cleaned manually before building polygon topology. Route systems representing faults (route.fault_thrust and route.fault_unclass) were created and attributed.
    (process 8 of 18)
    The coverage LAKES was extracted from the USGS 1:100,000 scale DLG hydrographic data. DLG data for the quadrangles of the study area were downloaded from the EROS Data Center and converted to ARC/INFO format. Features representing lakes, wetland areas, and rivers were placed in separate coverages. Finally, coverages from each quadrangle representing these features were appended and clipped to the extent of the project area.
    (process 9 of 18)
    The region features in the coverage LODES represent native copper lodes of the Keweenaw Peninsula. They were digitized from 1:24,000 scale geologic maps using GSMAP software and converted to ARC/INFO format. In ARC/INFO, polygon and region topology were constructed, and attribute tables added and populated.
    (process 10 of 18)
    The arc features in the coverage MAP represent distinct magnetic trends in the study area. They were digitized in GSMAP from a 1:250,000 scale hand-contoured magnetic compilation and converted to ARC/INFO format.
    (process 11 of 18)
    The coverage MINES were digitized from 1:24,000 scale geologic maps using GSMAP software and converted to ARC/INFO format. In ARC/INFO topology was built, and attribute fields added and populated.
    (process 12 of 18)
    The outcrop data in the coverage OUTCROP were generalized from 1:24,000 and 1:62,500 scale maps to 1:100,000 scale mylar base maps. These sheets were scanned as TIFF's and converted to ARC/INFO using the IMAGEGRID command. The grids created were registered using the CONTROLPOINTS and GRIDWARP commands and then converted to vector coverages using the GRIDLINE command. Finally, the individual coverages were appended and polygon topology built.
    (process 13 of 18)
    The coverage RIVERS was extracted from the USGS 1:100,000 scale DLG hydrographic data and converted to ARC/INFO format. Features representing lakes, wetland areas, and rivers were placed in separate coverages. Finally, coverages from each quadrangle representing these feature types were appended and clipped to the extent of the project area.
    (process 14 of 18)
    The coverage ROADS was extracted from the USGS 1:100,000 scale SDTS transportation data. SDTS data for the study area were downloaded from the EROS Data Center and converted to ARC/INFO format. Coverages of individual quadrangles were then appended and attributed.
    (process 15 of 18)
    The arcs from the coverage STRUCTUR represent significant miscellaneous structural features in the project area. The syncline was digitized in GSMAP from a 1:62,500 scale geologic map. The Limestone Mountain Structural Zone is a newly published feature. It has been interpreted from aeromagnetic and gravity data. Its location and extent are supported by outcrop data. The zone was compiled on a 1:100,000 scale mylar base, digitized in GSMAP, and converted to ARC/INFO.
    (process 16 of 18)
    The polygon features in the coverage WETLANDS were extracted from 1:100,000 scale DLG hydrographic data. These DLG's were downloaded from the EROS Data Center and converted to ARC/INFO format. Features representing lakes, wetland areas, and rivers were placed in separate coverages. Finally, coverages from each quadrangle were appended and clipped to the extent of the project area.
    (process 17 of 18)
    The lines in the coverage XSECTION were drawn by the authors. They indicate where detailed cross sections were constructed. They were drawn on the 1:100,000 scale mylar base, digitized in GSMAP, and converted to ARC/INFO.
    Date: 24-Jul-2000 (process 18 of 18)
    Creation of original metadata record Person who carried out this activity:
    Jennifer Lenz
    US Geological Survey
    12201 Surise Valley Drive, Mail Stop 918
    Reston, VA
    USA

    703-648-6974 (voice)
    703-648-6560 (FAX)
    pschweitzer@usgs.gov
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    complete
  5. How consistent are the relationships among the observations, including topology?
    This digital database was compiled from a variety of sources which are documented on the file README.doc.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints: None
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey Information Services
    Box 25248, Denver Federal Center
    Denver, CO
    USA

    1-888-ASK-USGS (voice)
    1-303-202-4693 (FAX)
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
    This database, identified as "Geology and Mineral Deposits of the Keweenaw Peninsula and Vicinity, Michigan" has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-Jun-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA
USA

703-648-6533 (voice)
703-648-6252 (FAX)
pschweitzer@usgs.gov
Metadata standard:
Content for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://geo-nsdi.er.usgs.gov/metadata/open-file/99-149/metadata.faq.html>
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