GEOLOGY AND MINERAL DEPOSITS OF THE KEWEENAW PENINSULA, MICHIGAN

William F. Cannon, Suzanne W. Nicholson - U.S. Geological Survey 
Michele E. McRae - U.S. Geological Survey, Oak Ridge Associated Universities 

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.

PURPOSE
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.

SPATIAL DATA DESCRIPTION
The following is a list of data layers in this ArcView project and a brief description of the features contained in each.  The list is followed by a detailed information on each coverage containing entity information, a brief description of attribute fields, and procedures used to develop individual data layers.  All data were imported to ArcView 3.1 using the ARC/INFO .e00 interchange format.

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

         *****Description of DOUBLE precision coverage ATTITUDE*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
POINTS                                    195        78
ANNOTATIONS                 DIP           195
 
                               SECONDARY FEATURES
 
Tics                                       12
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -88.997            Xmax =                  -87.606
Ymin =                   46.441            Ymax =                   47.480

						STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of point attribute table attitude.pat:
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  AREA                   8    18     F      5                        -
    9  PERIMETER              8    18     F      5                        -
   17  ATTITUDE#              4     5     B      -                        -
   21  ATTITUDE-ID            4     5     B      -                        -
   25  TYPE                  40    40     C      -                        -
   65  STRIKE                 7     7     I      -    P1                  -
   72  DIP                    3     3     I      -    P2                  -
   75  ANGLE                  3     3     I      -                        -

Description of author-defined items in attitude.pat:
*TYPE - Specifies the type of feature described by symbol (i.e., stike and dip of bedding, strike and dip of cleavage, strike and dip of foliation, strike of  vertical bed)
*STRIKE - Strike (the alternate name P1 is the original field name assigned by GSMAP)
*DIP - Dip angle (the alternate name P2 is the original field name assigned by GSMAP)
*ANGLE - An rotation angle for use with ArcView which allows the user to correctly orient the symbols

PROCEDURES:  These point features 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.

         *****Description of DOUBLE precision coverage BURIED*****
                                FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                       43        48
NODES                                      58
ANNOTATIONS               LABEL             8
 
                               SECONDARY FEATURES
 
Tics                                        8
Arc Segments                              758
 
                                   TOLERANCES
 
Fuzzy   =                 0.000 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -88.994            Xmax =                  -88.159
Ymin =                   46.447            Ymax =                   47.350
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table buried.aat:  
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 8    18     F      5                        -
   25  BURIED#                4     5     B      -                        -
   29  BURIED-ID              4     5     B      -                        -
   33  TYPE                  15    15     C      -                        -
 
Description of author-defined items in buried.aat:
*TYPE - The type of feature (concealed contact or concealed thrust) buried beneath the Jacobsville Sandstone.

PROCEDURES:  These previously unpublished features are 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.

         *****Description of DOUBLE precision coverage CGL*****
                                FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                      161        56
NODES                                    1850
ANNOTATIONS              SYMBOL            30
 
                               SECONDARY FEATURES
 
Tics                                        4
Arc Segments                             3175
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.034            Xmax =                  -87.491
Ymin =                   46.527            Ymax =                   47.487
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table cgl.aat:
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 8    18     F      5                        -
   25  CGL#                   4     5     B      -                        -
   29  CGL-ID                 4     5     B      -                        -
   33  NAME                  20    20     C      -                        -
   53  SYMBOL                 4     4     C      -                        -
 
Description of author-defined items in cgl.aat:
*NAME - Name of interflow conglomerate
*SYMBOL - Abbreviation for named conglomerate that corresponds to the symbol used on the USGS 1:100,000 scale Geologic Map of the Keweenaw Peninsula, Michigan

PROCEDURES:  These arcs 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.

         *****Description of DOUBLE precision coverage CHALC*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                        5        32
POLYGONS                                    6        56               Yes
NODES                                       5
 
                               SECONDARY FEATURES
 
Tics                                        4
Arc Segments                               72
Polygon Labels                              5
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 V          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY

Xmin =                  -88.208            Xmax =                  -88.012
Ymin =                   47.353            Ymax =                   47.395
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of polygon attribute table chalc.pat: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  AREA                   8    18     F      5                        -
    9  PERIMETER              8    18     F      5                        -
   17  CHALC#            4     5     B      -                        -
   21  CHALC-ID          4     5     B      -                        -
   25  NAME                  20    20     C      -                        -
   45  RESOURCE_TONNAGE       7     7     I      -                        -
   52  GRADE                  4     4     F      2                        -
 
Description of items in chalc.pat:
*NAME - Name of chalcocite body
*RESOURCE_TONNAGE - Size of economic portion of body in tons
*GRADE - Grade of economic portion of body in %Cu

PROCEDURES:  These polygons 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.   

         *****Description of DOUBLE precision coverage COORD*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                       44        32
NODES                                    1875
ANNOTATIONS               COORD            48
 
                               SECONDARY FEATURES
 
Tics                                        4
Arc Segments                               47
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.000            Xmax =                  -87.500
Ymin =                   46.000            Ymax =                   47.500
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Note:  There are no author-defined attributes for this coverage.

PROCEDURES:  This coverage 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.

         *****Description of DOUBLE precision coverage FISSURE*****
                                FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                       49       104
NODES                                     126
 
                               SECONDARY FEATURES
 
Tics                                        4
Arc Segments                              105
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.034            Xmax =                  -87.491
Ymin =                   46.527            Ymax =                   47.487
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table fissure.aat: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?     1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 8    18     F      5                        -
   25  FISSURE#               4     5     B      -                        -
   29  FISSURE-ID             4     5     B      -                        -
   33  NAME                  15    15     C      -                        -
   48  OWNER                 30    30     C      -                        -
   78  TOTAL_PRODUCTION      16    16     N      0                        -
   94  YEARS_PRODUCTION      10    10     C      -                        -

Description of author-defined items in fissure.aat:
*NAME - Name of fissure vein
*OWNER - Owner of fissure vein
*TOTAL_PRODUCTION - Total production of fissure in pounds
*YEARS_PRODUCTION - Years in production

Note:  A value of -9999 in the TOTAL_PRODUCTION field indicates no data.

PROCEDURES:  These arcs represent fissure veins.  They 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.
 

         *****Description of DOUBLE precision coverage GEOLOGY*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                      856        32
POLYGONS                                  178       576               Yes
NODES                                     719
ANNOTATIONS              SYMBOL           117
                          FAULT            16
ROUTES/SECTIONS          THRUST          7/85     28/58
                          FAULT        71/298     34/32
 
                               SECONDARY FEATURES
 
Tics                                        8
Arc Segments                            11807
Polygon Labels                            177
 
                                   TOLERANCES

Fuzzy   =                 0.002 V          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.000            Xmax =                  -87.498
Ymin =                   46.421            Ymax =                   47.480
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of items in polygon attribute table geology.pat:
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  AREA                   8    18     F      5                        -
    9  PERIMETER              8    18     F      5                        -
   17  GEOLOGY#               4     5     B      -                        -
   21  GEOLOGY-ID             4     5     B      -                        -
   25  CODE                   3     3     I      -                        -
   28  SYMBOL                 5     5     C      -                        -
   33  ERA                   12    12     C      -                        -
   45  PERIOD                22    22     C      -                        -
   67  SUBPERIOD             28    28     C      -                        -
   95  SUPERGROUP            15    15     C      -                        -
  110  GROUP                 20    20     C      -                        -
  130  UNIT_NAME             38    50     C      -                        -
  168  SUBUNIT_NAME          20    20     C      -                        -
  188  AGE                    9     9     C      -                        -
  197  RK_TYPE               11    11     C      -                        -
  208  MAJOR_SUBTYPE         15    15     C      -                        -
  223  MAJOR_LITHOLOGY       21    21     C      -                        -
  244  MINOR1_RKTYPE         12    12     C      -                        -
  256  MINOR1_SUBTYPE        15    15     C      -                        -
  271  MINOR1_LITHOLOGY      25    25     C      -                        -
  296  MINOR2_RKTYPE         12    12     C      -                        -
  308  MINOR2_SUBTYPE        15    15     C      -                        -
  323  MINOR2_LITHOLOGY      20    20     C      -                        -
  343  PROVINCE_ORIGIN       28    28     C      -                        -
  371  SUBPROV/TERRANE       40    40     C      -                        -
  411  PROVINCE_AGE          18    18     C      -                        -
  429  REWORKING_PROV         8     8     C      -                        -
  437  REWORKING_SUBPRO      20    20     C      -                        -
  457  REWORKING_AGE         18    18     C      -                        -
  475  ENV_OF_FORMATION      26    26     C      -                        -
  501  TECTONIC_SETTING      24    24     C      -                        -
  525  LITH_ASSEMBLAGE       52    52     C      -                        -

Description of author-defined items in geology.pat:
*CODE - Code used to join polygon to attributes
*SYMBOL - Abbreviation of named unit
*ERA - Era
*PERIOD - Period
*SUBPERIOD - Subperiod
*SUPERGROUP - Supergroup
*GROUP - Group
*UNIT_NAME - Name of geologic unit
*SUBUNIT_NAME - Subdivision within geologic unit
*AGE - Age of geologic unit millions of years
*RK_TYPE - Primary rock type of named unit
*MAJOR_SUBTYPE - Further subdivision of RK_TYPE
*MAJOR_LITHOLOGY - Predominant lithology of RK_TYPE
*MINOR1_RKTYPE - Other rock type within named unit (note:  designations minor1 and minor2 do not indicate abundance)
*MINOR1_SUBTYPE - Further subdivision of MINOR1_RKTYPE
*MINOR1_LITHOLOGY - Predominant lithology of MINOR1_RKTYPE
*MINOR2_RKTYPE - Other rock type within named unit
*MINOR2_SUBTYPE - Further subdivision of MINOR2_RKTYPE
*MINOR2_LITHOLOGY - Predominant lithology of MINOR2_RKTYPE
*PROVINCE_ORIGIN - Province of origin
*SUBPROV/TERRANE - Subprovince/terrane of origin
*PROVINCE_AGE - Age of province of origin
*REWORKING_PROV - Province of reworking (if applicable)
*REWORKING_SUBPROV - Subprovince of reworking
*REWORKING_AGE - Age of reworking
*ENV_OF_FORMATION - Environment of formation
*TECTONIC_SETTING - Tectonic setting
*LITH_ASSEMBLAGE - Lithologic assemblage

Description of route attribute table geology.ratfault: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FAULT#                 4     5     B      -                        -
    5  FAULT-ID               4     5     B      -                        -
    9  NAME                  25    25     C      -                        -

Description of author-defined items in geology.ratfault:
*NAME - Name of unclassified fault
 
Description of route attribute table geology.ratthrust:  COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  THRUST#                4     5     B      -                        -
    5  THRUST-ID              4     5     B      -                        -
    9  NAME                  20    20     C      -                        -

Description of author-defined items in geology.ratthrust:
*NAME - Name of thrust fault

PROCEDURES:  Geology and faults 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.

         *****Description of DOUBLE precision coverage LAKES*****
                                FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                      457        32
POLYGONS                                  362        26               Yes
NODES                                     454
ANNOTATIONS                NAME            16
 
                               SECONDARY FEATURES
 
Tics                                        8
Arc Segments                            10995
Polygon Labels                            361
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 V          Dangle  =                 0.000 N
 
Continue? |
                               COVERAGE BOUNDARY
 
Xmin =                  -88.999            Xmax =                  -87.608
Ymin =                   46.423            Ymax =                   47.477
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of polygon attribute table lakes.pat: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  AREA                   8    18     F      5                        -
    9  PERIMETER              8    18     F      5                        -
   17  LAKES#                 4     5     B      -                        -
   21  LAKES-ID               4     5     B      -                        -
   25  LAKE                   1     1     C      -                        -
 
Description of author-defined items in lakes.pat:
*LAKE - Indicates whether specified polygon is a lake or land mass, either 'y' or 'n'

PROCEDURES:  This coverage 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.

         *****Description of DOUBLE precision coverage LODES*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                       67        32
POLYGONS                                   33        24               Yes
NODES                                      55
REGIONS                IROQUOIS             1       120               Yes
                       KEARSARG             4       440               Yes
                       HOUGHTON             1       120               Yes
                        OSCEOLA             2       180               Yes
                          CANDH             3       220               Yes
                        ALLOUEZ             2       200               Yes
                        ISLEROY             1       180               Yes
                         BALTIC             5       200               Yes
                         ASHBED             3       260               Yes
                        PEWABIC             2       200               Yes
                       KINGSTON             1       120               Yes
 
                               SECONDARY FEATURES
 
Tics                                        4
Arc Segments                             1056
Polygon Labels                             33
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 V          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -88.698            Xmax =                  -88.192
Ymin =                   47.010            Ymax =                   47.429
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866

Description of region attribute table lode.patkearsarg (NOTE:  Only the description of this region attribute table is included.  The items in all other region attribute tables (lode.patiroquois, lode.pathoughton, lode.patosceola, lode.patcandh, lode.patallouez, lode.patisleroy, lode.patbaltic, lode.patashbed, lode.patpewabic, and lode.patkingston) are identical except that there are fewer fields for mines.  
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?     1  AREA                   8    18     F      5                        -
    9  PERIMETER              8    18     F      5                        -
   17  KEARSARG#              4     5     B      -                        -
   21  KEARSARG-ID            4     5     B      -                        -
   25  LODE_NAME             30    30     C      -                        -
   55  MINE_1                20    20     C      -                        -
   75  MINE_2                20    20     C      -                        -
   95  MINE_3                20    20     C      -                        -
  115  MINE_4                20    20     C      -                        -
  135  MINE_5                20    20     C      -                        -
  155  MINE_6                20    20     C      -                        -
  175  MINE_7                20    20     C      -                        -
  195  MINE_8                20    20     C      -                        -
  215  MINE_9                20    20     C      -                        -
  235  MINE_10               20    20     C      -                        -
  255  MINE_11               20    20     C      -                        -
  275  MINE_12               20    20     C      -                        -
  295  MINE_13               20    20     C      -                        -
  315  MINE_14               20    20     C      -                        -
  335  MINE_15               20    20     C      -                        -
  355  MINE_16               20    20     C      -                        -
  375  MINE_17               20    20     C      -                        -
  395  TOTAL_PRODUCTION      16    16     N      2                        -
  411  YEARS_PRODUCTION      10    10     C      -                        -
  421  IDED_RESERVES         16    16     N      2                        -
  437  RESERVE_GRADE          4     4     N      2                        -
 
Description of user-defined items in lode.patkearsarg and other region attribute tables:
*LODE_NAME - Name of native copper lode
*MINE_1 through MINE_17 - Names of mines that worked the lode
*TOTAL_PRODUCTION - Total native copper production of lode in pounds
*YEARS_PRODUCTION - Years lode was in production
*IDED_RESERVES - Estimate of ore remaining in lode in units of thousands of tonnes
*RESERVE_GRADE - Grade of identified reserves

Note:  Values of 0.00 in the IDED_RESERVES field indicate that no data is available.

PROCEDURES:  Region features in this coverage 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.

 
         *****Description of DOUBLE precision coverage MAG*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                        8        32
ANNOTATIONS               LABEL             9
 
                               SECONDARY FEATURES
 
Tics                                        4
Arc Segments                              159
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.034            Xmax =                  -87.491
Ymin =                   46.527            Ymax =                   47.487
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Note:  There are no author-defined items in this coverage.

PROCEDURES:  These arc features 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.

         *****Description of DOUBLE precision coverage MINES*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
POINTS                                    363       114
 
                               SECONDARY FEATURES
 
Tics                                        4
 
                                   TOLERANCES
 
Fuzzy   =                 0.000 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -88.683            Xmax =                  -87.801
Ymin =                   47.022            Ymax =                   47.467
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of point attribute table mines.pat: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  AREA                   8    18     F      5                        -
    9  PERIMETER              8    18     F      5                        -
   17  MINES#                 4     5     B      -                        -
   21  MINES-ID               4     5     B      -                        -
   25  MINE_NAME             50    50     C      -                        -
   75  SHAFT_NAME            10    10     C      -                        -
   85  LODE_NAME             30    30     C      -                        -

Description of author-defined items in mines.pat:
*MINE_NAME - Name of mine owning shaft
*SHAFT_NAME - Name of mine shaft
*LODE_NAME - Name of primary lode being worked by shaft (in some cases, a shaft may have penetrated more than one lode)

PROCEDURES:  These points represent the location of mine shafts.  They 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. 

         *****Description of DOUBLE precision coverage OUTCROPS*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                     1217        32
POLYGONS                                 1168        24               Yes
NODES                                    1205
 
                               SECONDARY FEATURES
 
Tics                                       12
Arc Segments                            54887
Polygon Labels                           1168
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 V          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY

Xmin =                  -88.999            Xmax =                  -87.587
Ymin =                   46.434            Ymax =                   47.480
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Note:  No author-defined attributes in this coverage

PROCEDURES:  Outcrop data 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.

         *****Description of SINGLE precision coverage RIVERS*****
                                FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                     2163        76
NODES                                    6219
 
                               SECONDARY FEATURES
 
Tics                                       16
Arc Segments                            52411
 
                                   TOLERANCES
 
Fuzzy   =                 0.000 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.000            Xmax =                  -87.500
Ymin =                   46.421            Ymax =                   47.500
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table rivers.aat: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 4    12     F      3                        -
   21  RIVERS#                4     5     B      -                        -
   25  RIVERS-ID              4     5     B      -                        -
   29  MAJOR1                 6     6     I      -                        -
   35  MINOR1                 6     6     I      -                        -
   41  MAJOR2                 6     6     I      -                        -
   47  MINOR2                 6     6     I      -                        -
   53  MAJOR3                 6     6     I      -                        -
   59  MINOR3                 6     6     I      -                        -
   65  MAJOR4                 6     6     I      -                        -
   71  MINOR4                 6     6     I      -                        -

Description of items in rivers.aat:
*MAJOR1 - DLG code
*MINOR1 - DLG code
*MAJOR2 - DLG code
*MINOR2 - DLG code
*MAJOR3 - DLG code
*MINOR3 - DLG code
*MAJOR4 - DLG code
*MINOR4 - DLG code

PROCEDURES:  This coverage 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. 

         *****Description of DOUBLE precision coverage ROADS*****
                                FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                     9122        52
 
                               SECONDARY FEATURES
 
Tics                                       20
Arc Segments                            55434
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.000            Xmax =                  -87.714
Ymin =                   46.421            Ymax =                   47.500

                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table roads.aat:
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -     5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 8    18     F      5                        -
   25  ROADS#                 4     5     B      -                        -
   29  ROADS-ID               4     5     B      -                        -
   33  TYPE                  20    20     C      -                        -

Description of author-defined items in roads.aat:
*TYPE - Designates road type following conventions of USGS 1:100,000 scale topographic maps.

PROCEDURES:  This coverage 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.

 
         *****Description of DOUBLE precision coverage STRUCTUR*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                        2        64
ANNOTATIONS               LABEL             2
 
                               SECONDARY FEATURES
 
Tics                                        8
Arc Segments                               42
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.034            Xmax =                  -87.491
Ymin =                   46.442            Ymax =                   47.487
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table structur.aat:
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 8    18     F      5                        -
   25  STRUCTUR#             4     5     B      -                        -
   29  STRUCTUR-ID           4     5     B      -                        -
   33  TYPE                  32    32     C      -                        -

Description of author-defined items in structur.aat:
*TYPE - The structural feature type.  In this case either 'syncline' or 'Limestone Mtn. Structural Zone'

PROCEDURES:  These arcs 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.

         *****Description of SINGLE precision coverage WETLANDS*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                      478        76
POLYGONS                                  148        16               Yes
NODES                                     473
 
                               SECONDARY FEATURES
 
Tics                                       16
Arc Segments                            14185
Polygon Labels                            147
 
                                   TOLERANCES
 
Fuzzy   =                 0.000 V          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY

Xmin =                  -89.000            Xmax =                  -87.733
Ymin =                   46.422            Ymax =                   47.459
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Datum                     NAD27
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table wetlands.aat:
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 4    12     F      3                        -
   21  WETLANDS#              4     5     B      -                        -
   25  WETLANDS-ID            4     5     B      -                        -
   29  MAJOR1                 6     6     I      -                        -
   35  MINOR1                 6     6     I      -                        -
   41  MAJOR2                 6     6     I      -                        -
   47  MINOR2                 6     6     I      -                        -
   53  MAJOR3                 6     6     I      -                        -
   59  MINOR3                 6     6     I      -                        -
   65  MAJOR4                 6     6     I      -                        -
   71  MINOR4                 6     6     I      -                        -

Description of items in wetlands.aat:
*MAJOR1 - DLG code
*MINOR1 - DLG code
*MAJOR2 - DLG code
*MINOR2 - DLG code
*MAJOR3 - DLG code
*MINOR3 - DLG code
*MAJOR4 - DLG code
*MINOR4 - DLG code

PROCEDURES:  The polygon features in this coverage 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.

 
         *****Description of DOUBLE precision coverage XSECTION*****
                                 FEATURE CLASSES
 
                                    Number of  Attribute     Spatial
Feature Class          Subclass     Features   data (bytes)  Index?   Topology?
-------------          --------     ---------  ------------  -------  ---------
ARCS                                        3        70
ANNOTATIONS               LABEL             7
 
                               SECONDARY FEATURES
 
Tics                                        8
Arc Segments                                3
 
                                   TOLERANCES
 
Fuzzy   =                 0.002 N          Dangle  =                 0.000 N
 
                               COVERAGE BOUNDARY
 
Xmin =                  -89.000            Xmax =                  -87.500
Ymin =                   46.500            Ymax =                   47.500
 
                                     STATUS
 
The coverage has not been Edited since the last BUILD or CLEAN.
 
                          COORDINATE SYSTEM DESCRIPTION
 
Projection           GEOGRAPHIC
Units                        DD             Spheroid             CLARKE1866
Parameters:

Description of arc attribute table xsection.aat: 
COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME     INDEXED?
    1  FNODE#                 4     5     B      -                        -
    5  TNODE#                 4     5     B      -                        -
    9  LPOLY#                 4     5     B      -                        -
   13  RPOLY#                 4     5     B      -                        -
   17  LENGTH                 8    18     F      5                        -
   25  XSECTION#              4     5     B      -                        -
   29  XSECTION-ID            4     5     B      -                        -
   33  ID                     2     2     C      -                        -
    
Description of author-defined items in xsection.aat:
*ID - Identifies cross section

PROCEDURES:  These lines 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.  

OTHER DIGITAL DATA

In addition to the above named layers, this project contains cross sections which are also structured as ARC/INFO coverages.  Although, these data layers contain attributes and georeferencing information, they are not true geographic data.  Rather, they were structured as coverages to allow correct scaling and positioning with respect to map view data.  There are two copies of each cross section.  The first set of cross sections was oriented horizontally and placed in individual views labeled Cross Section A-A', Cross Section B-B', and Cross Section C-C'.  The other set has been rotated to align with the cross section lines in the map view.  This allows the user to view the cross sections in relation to the geologic units.  The following are cross section coverage names:

XA_MAPVIEW
XB_MAPVIEW
XC_MAPVIEW
XA_HORIZ
XB_HORIZ
XC_HORIZ

Several images have been included for reference.  Each was placed in a separate view.  These images include: 

INDEXMAP.TIF - Index of geologic quadrangle maps used in compilation
CORDIAG.TIF - Correlation Diagram, Eagle Harbor to South Range
STRATSEC.TIF  - Correlation of Map Units

REFERENCES
(asterisk indicates sources used for map compilation)
 
Barovich, K.M., Patchett, P.J., Peterman, Z.E., and Sims, P.K., 1989,
Nd Isotopes and the Origin of the 1.9-1.7 Ga Penokean Continental Crust in
the Lake Superior Region:  Geological Society of America Bulletin, v. 101,
p. 333-338.
 
Bornhorst, T.J., Paces, J.B., Grant, N.K., Obradovich, J.D., and Huber, N.K.,
1988, Age of Native Copper Mineralization Keweenaw Peninsula, Michigan:
Economic Geology, v. 83, p. 619-625.
 
Brojanigo, A., 1984, Keweenaw Fault:  Structures and Sedimentology: Houghton,
Michigan, Michigan Technological University, M.S. thesis, 124 p.
 
Bodwell, W.A., 1972, Geologic Compilation and Nonferrous Metal Potential,
Precambrian Section, Northern Michigan:  Houghton Michigan, Michigan
Technological University, M.S. thesis, 106 p.
 
Butler, B.S., and Burbank, W.S., 1929, The Copper Deposits of Michigan:
U.S. Geological Survey Professional Paper 144, 238 p.
 
*Cannon, W.F., 1986, Bedrock Geologic Map of the Iron River 1x2 degree
Quadrangle, Michigan and Wisconsin:  U.S. Geological Survey Miscellaneous
Investigations Series Map I-1360-B, scale 1:250,000.
 
Cannon, W.F., Green, A.G., Hutchinson, D.R., Lee, M., Milkereit, B., Behrendt
J.C., Halls, H.C., Green, J.C., Dickas, A.B., Morey, G.B., Sutcliffe, R., and
Spencer, C., 1989, The North American Midcontinent Rift beneath Lake Superior
from GLIMPCE seismic reflection profiling: Tectonics, v. 8, p. 305-332.
 
*Cannon, W.F., and Klasner, J.S., 1980, Bedrock Geologic Map of the Kenton-
Perch Lake Area, Northern Michigan:  U.S. Geological Survey Miscellaneous
Investigations Series Map I-1290, scale 1:62,500.
 
Cannon, W.F., Nicholson, S.W., Zartman, R.E., Peterman, Z.E., and Davis, D.W.,
1993a, The Kallander Creek Volcanics -- a Remnant of a Keweenawan Central
Volcano Centered near Mellen, Wisconsin:  39th Annual Institute on Lake
Superior Geology Proceedings, p. 20-21.
 
Cannon, W.F., Peterman, Z.E., and Sims, P.K., 1993b, Crustal Scale Thrusting
and Origin of the Montreal River Monocline -- a 35km Thick Cross Section of
the Midcontinent Rift in Northern Michigan and Wisconsin:  Tectonics, v. 12, p.
728-744.
 
Cannon, W.F., Nicholson, S.W., Woodruff, L.G., Hedgman, C.A., and Schulz,
K.J., 1995, Geologic Map of the Ontonagon and part of the Wakefiled 30'x60'
Quadrangles, Michigan:  U.S. Geological Survey Miscellaneous Investigations Map
I-2499, scale 1:100,000.
 
Cannon, W.F., Woodruff, L.G., Nicholson, S.W., and Hedgman, C.A., 1996,
Bedrock Geologic Map of the Ashland and Northern Part of the Ironwood
30'x60' Quadrangles, Wisconsin and Michigan:  U.S. Geological Survey
Miscellaneous Investigations Map I-2566, scale 1:100,000.
 
 
Case, E.C., and Robinson, W.I., 1915, The Geology of Limestone Mountain and
Sherman Hill in Houghton County, Michigan:  Michigan Geological and Biological
Survey, Publication 18, p. 165-181.
 
*Cornwall, H.R., 1954a, Bedrock Geology of the Delaware Quadrangle, Michigan:
U.S. Geological Survey Quadrangle Map GQ-51, scale 1:24,000.
 
*Cornwall, H.R., 1954b, Bedrock Geology of the lake Medora Quadrangle,
Michigan:  U.S. Geological Survey Geological Quadrangle Mpa GQ-52, scale
1:24,000.
 
*Cornwall, H.R., 1954c, Bedrock Geology of the Phoenix Quadrangle, Michigan:
U.S. Geological Survey Geological Quadrangle Map GQ-34, scale 1:24,000.
 
*Cornwall, H.R., 1955, Bedrock Geology of the Fort Wilkins Quadrangle, Michigan:
U.S. Geological Survey Geological Quadrangle Map GQ-74, scale 1:24,000.
 
*Cornwall, H.R., and White, W.S., 1955, Bedrock Geology of the Manitou Island
Quadrangle, Michigan:  U.S. Geological Survey Geological Quadrangle Map
GQ-73, scale 1:24,000.
 
*Cornwall, H.R., and Wright, J.C., 1954, Bedrock Geology of the Eagle Harbor
Quadrangle, Michigan:  U.S. Geological Survey Geological Quadrangle Map
GQ-36, scale 1:24,000.
 
*Cornwall, H.R., and Wright, J.C., 1956a, Geologic Map of the Hancock
Quadrangle, Michigan:  U.S. Geological Survey Mineral Investigations Field
Studies Map MF-46, scale 1:24,000.
 
*Cornwall, H.R., and Wright, J.C., 1956b, Geologic Map of the Laurium
Quadrangle, Michigan:  U.S. Geological survey Mineral Investigations Field
Studies Map MF-47, scale 1:24,000.
 
Daniels, P.A., Jr., 1982, Upper Precambrian Sedimentary Rocks:  Oronto Group,
Michigan-Wisconsin, in Wold. R.J. and W.J. Hinze, eds., Geology and
Tectonics of the Lake Superior Basin:  Geological Society of America Memoir
156, p. 107-133.
 
*Davidson, E.S., Espenshade, G.H., White, W.S., and Wright, J.C., 1955,
Bedrock Geology of the Mohawk Quadrangle, Michigan:  U.S. Geological Survey
Geological Survey Quadrangle Map GQ-54, scale 1:24,000.
 
Davis, D.W., and Sutcliffe, R.H., 1985, U-Pb Ages from the Nipigon Plate
and Northern Lake Superior:  Geological Society of America Bulletin, v. 96,
p. 1572-1579.
 
Davis, D.W., Paces, J.B., 1990, Time Resolution of Geologic Events on the
Keweenaw Peninsula and implications for development of the Midcontinent Rift:
Earth and Planetary Science Letters, v. 97, p. 54-64.
 
*Gregg, W.J., 1993, Structural Geology of Parautochthonous and Allocthonous
Terranes of the Penokean Orogeny in Upper Michigan -- Comparisons with
Northern Appalachian Tectonics:  U.S. Geological Survey Bulletin, 1904-Q,
p. Q1-Q28.
 
Hedgman, C.A., 1992, Petrology and Provenance of a Conglomerate Facies of the
Jacobsville Sandstone:  Ironwood to Bergland, Michigan:  [abst.] 38th
Annual Institute on Lake Superior Geology Proceedings, v. 38, p.32-33.
 
James, H.L., 1955, Zones of Regional Metamorphism in the Precambrian of
Northern Michigan:  Geological Society of America Bulletin, v. 66, p.
1455-1488.
 
Kalliokoski, J., 1982, Jacobsville Sandstone, in Wold, R.J. and Hinze, W.J.,
eds., Geology and Tectonics of the Lake Superior Basin:  Geological Society
of America Memoir 156, p. 147-155.
 
Mauk, J.L., Kelly, W.C., van der Pluijm, B.A., and Seasor, R.W., 1992,
Relations between Deformation and Sediment-hosted Copper Mineralizations:
Evidence from the White Pine Portion of the Midcontinent Rift System:
Geology, v. 20, p. 427-430.
 
Michcan Copper Company Ltd., 1982, Michigan Copper Sulfide Project, Keweenaw
Peninsula:  unpublished company document, 21 p.
 
Nicholson, S.W., 1992, Geochemistry, Petrography and Volcanology of Rhyolites
of the Portage Lake Volcanics, Keweenaw Peninsula, Michigan:  U.S. Geological
Survey Bulletin 1970-B, p. B1-B57.
 
Ojakangas, R.W., 1994, Sedimentology and Provenance of the Early Proterozoic
Michigamme Formation and Goodrich Quartzite, Northern Michigan - Regional
Stratigraphic Implications and Suggested Correlations:  U.S. Geological Survey
Bulletin 1904-R, p. R1-R31.
 
Robertson, J.M., 1975, Geology and Mineralogy of some Copper Sulfide Deposits
near Mount Bohemia, Keweenaw County, Michigan:  Economic Geology, v. 70,
p. 1202-1224.
 
Waggoner, T.D., 1994, Echo Lake Gabbro, Houghton County, Michigan [abs.]:
40th Annual Institute on Lake Superior Geology, Proceedings, Part 1 - Program
and abstracts, p. 70.
 
*White, W.S., 1956, Geologic Map of the Chassell Quadrangle, Michigan:  U.S.
Geological Survey Minerals Investigations Field Studies Map MF-43, scale
1:24,000.
 
*White, W.S., 1968, The Native Copper Deposits of Northern Michigan, in Ridge,
J.D., ed., Ore Deposits of the United States of 1933-1967 (Graton-Sales
volume):  New York, American Institute of Mining, Metallurgy and Petroleum
Engineers, v. 1, p. 303-325.
 
*White, W.S., Cornwall, H.R., and Swanson, R.W., 1953, Bedrock Geology of the
Ahmeek Quadrangle, Michigan:  U.S. Geological Survey Geological Quadrangle
Map GQ-27, scale 1:24,000.
 
*White, W.S., and Wright, J.C., 1956, Geologic Map of the South Range
Quadrangle, Michigan:  U.G. Geological Survey Minerals Investigations Field
Studies Map MF-48, scale 1:24,000.
 
White, W.S., and Wright, J.C., 1966, Sulfide Mineral Zoning in the Basal
Nonesuch Shale, Northern Michigan:  Economic Geology, v. 61, p. 1171-1190.
 
Wilband, J.T., 1978, The Copper Resources of Northern Michigan:  Final Report
under U.S. Bureau of Mines contract J0366067, 61 p.
 
*Wright, J.C., and Cornwall, H.R., 1954, Bedrock Geology of the Bruneau
Creek Quadrangle, Michigan:  U.S. Geological Survey Geologic Quadrangle Map
GQ-35, scale 1:24,000.
 
Young, C.T., and Repasky, T.R., 1986, A Magnetotelluric Transect of the
Jacobsville Sandstone in Northern Michigan:  Geological Society of America
Bulletin, v. 97, p. 711-716.

REVIEWS
A paper copy of this data set was printed and reviewed for content and
accuracy.  The paper copy was then submitted to the USGS publications group
for publication of the traditional geologic map.  For the review of tabular
data, coverages were converted to ArcView.  A variety of queries and searches
were performed to check for typographic and content errors.  
 

STATUS
Complete

MAINTENANCE AND UPDATE FREQUENCY
None planned

ACCESS CONSTRAINTS
None

USE CONSTRAINTS
None

POINT OF CONTACT
Bill Cannon
MS 954, USGS
Reston, VA 20192
(703) 648-7345
wcannon@usgs.gov