# KODIAK_README.PDF

# PRELIMINARY INTEGRATED GEOLOGIC MAP DATABASES FOR THE UNITED STATES:

# DIGITAL DATA FOR THE RECONNAISSANCE GEOLOGIC MAP FOR THE KODIAK ISLANDS, ALASKA

# 

# by

# Digital files prepared by: Frederic H. Wilson(1), Keith A. Labay(2), Solmaz Mohadjer(3), and Nora Shew(1)

# Geologic map by: Frederic H. Wilson(1)

\(1\) U.S. Geological Survey, 4200 University Dr., Anchorage, AK
99508-4667; (2) Contractor, SAIC, U.S. Geological Survey, 4200
University Dr., Anchorage, AK 99508-4667; (3) Contractor, Kelly
Services, U.S. Geological Survey, 4200 University Dr., Anchorage, AK
99508-4667

# DISCLAIMERS

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# INTRODUCTION

These digital files represent part of a systematic effort to release
geologic map data for the United States in a uniform manner. Geologic
data in this series has been compiled from a wide variety of sources,
ranging from state and regional geologic maps to large-scale field
mapping. It is presented for use at a nominal scale of 1:500,000,
although individual datasets may contain data for use at larger scales.
The metadata associated with each release will provide more detailed
information on sources and appropriate scales for use. Associated
attribute databases accompany the spatial database of the geology and
are similarly uniformly structured for ease in developing regional- and
national-scale maps.

The 1:500,000-scale reconnaissance geologic map of the Kodiak Islands,
Alaska covers more than 4,900 square miles (12,800 square kilometers) of
south central Alaska. The Kodiak Islands are located on the west side of
the Gulf of Alaska and are one of the largest areas of exposure of the
flysch and melange of the Chugach terrane of southern Alaska. However,
in the past 25 years, only detailed mapping, covering small areas in the
archipelago has been done.

The primary source for this map for Kodiak Island and south is the
reconnaissance mapping of George W. Moore (1967) augmented with unit
descriptions from George W. Moore (1969) and new mapping along the west
coast of the islands by Connelly and J. Casey Moore (Connelly, 1978;
Connelly and Moore, 1979) and on the east coast by Moore and others
(1983). George Moore's map in turn is heavily based on Capps (1937),
which is the major source for the Afognak Island part of the present
map.

The digital datasets that form the basis for this product were compiled
and created using existing published and unpublished data. The spatial
and text databases here are linked through use of a field, called
*nsaclass*, that is related to the age and lithology of the map units
contained on each map. *Nsaclass* and the similar *qclass* field have
been added to the polygon attribute table (PAT) of the spatial database
and are also found in the text databases of supplemental attribute data.
These fields store information that correlates individual map units
between sources. *Nsaclass* is used to make regional unit assignments
and generally reflects a known or an inferred correlation of map units.
For example, all "Surficial deposits, undivided" are assigned an
nsaclass code of 100. The schema for nsaclass was developed as regional
maps throughout Alaska were compiled and therefore reflects an iterative
process. As new or additional information becomes available, the
nsaclass code for a particular map unit may be changed, either to
reflect lumping or finer separation of map units. *Nsaclass* is used to
cover the entire geologic time scale, whereas *qclass* is restricted to
and provides finer detail for Quaternary map units. Fields called
*source* and *nsamod* have also been added to the PAT. Source is a coded
reference citation, indicating the manuscript or other source for the
map information. The format for *source* is XX###, where XX is the two
letter quadrangle code (CAPITAL letters) and \### is a three digit
number (using leading zeros) to indicate a specific reference. *Nsamod*
provides information with respect to hydrothermal alteration or contact
metamorphism of a map unit, either for the entire unit or for an
individual polygon. In this way, the *nsaclass* field needs to only
store the primary map unit information. Fields also in the PAT are
*class*, *label*, *min_age*, and *max_age* which are more fully
described in the accompanying documentation. Finally, a field called
*lith2* is in the PAT as a scratch field; no uniform schema has been
developed for this field.

The arc attribute table (AAT) stores attributes indicating the type of
line features in the coverages and shape files. Inherent in the coding
is information defining the type of line shown, such as a stratigraphic
or fault contact, and location (certain, approximate, inferred, or
concealed). In addition, each arc within a spatial database has a source
attribute.

The standardized supplemental attribute tables were generated by
extracting information from the legends of the source maps and from
unpublished data by the compilers of this regional map. Thus, the age
and lithologic information in the attribute tables may, in some cases,
conflict with the information on the legends of the original source
maps. This reflects new information for maps that may have been compiled
decades ago. The standardized supplemental attribute tables record an
abstracted map unit description, lithologic and age information, and
references.

The spatial databases are provided in the native UTM projection of the
sources as well as geographic coordinates. The UTM projection parameters
are described in the metadata, note that the datum is NAD '27. Regional
maps in Alaska are commonly presented using an Albers Equal-area
projection and the parameters for this projection are as follows:

Projection: Albers Equal-area

Horizontal datum: NAD'27

Spheroid: Clarke, 1866

1st Standard parallel: 55 degrees North

2nd Standard parallel: 65 degrees North

Central meridian: 154 degrees West

Latitude of projection origin: 50 degrees North

Units: meters

False easting (meters): 0

False northing (meters): 0

ArcView files can be viewed with the free viewer, ArcExplorer, which can
be downloaded from: http://www.esri.com/software/arcexplorer/.

These digital databases are the result of the compilation and
reinterpretation of published and unpublished 1:250,000- and
1:63,360-scale mapping. The map area covers approximately 12,800 sq km
(4,975 sq mi) in land area and encompasses parts of 5 1:250,000-scale
quadrangles in south central Alaska. The compilation was done as part of
the U.S. Geological Survey\'s National Surveys and Analysis project,
whose goal is to compile geologic, geochemical, geophysical, and other
data.

All geologic maps on which this compilation is based were published
using the Universal Transverse Mercator projection (UTM; Zone 5).
Because of the distortions use of the UTM projection would produce on a
map of small scale and large area, regional-scale products derived from
this data that cross UTM zones should be plotted using a more
appropriate Albers Equal-area projection.

# Kodiak Islands database tables

In order to manage the textural and coding information related to the
Kodiak Islands (Kodiak) geologic map, we have created a series of
related and interlinked databases. These databases are a subset of the
databases being created and maintained statewide. As provided here, they
include a runtime version of the primary databases, which are maintained
using the commercial Filemaker Pro (version 5 or 6) database software.
These databases are not directly connected to the ARC/INFO coverages;
however the data can be linked through the .csv or .dbf files that
accompany this report. However, these databases can used to guide
searches of the coverages seeking particular sorts of information. By
way of background the .PAT files of the coverages have 7 fields in them
that correspond to fields in the FP5 databases. These fields are
*class*, *nsaclass*, *qclass*, *label, min_ma, max_ma,* and *source*.

Nine database tables are included here. They are:

KODIAKUNITS: A subset of the statewide database containing abstracted
geologic unit descriptions for each source map in the Kodiak Islands.
The four .PAT fields, *class*, *nsaclass*, *qclass*, and *source*,
mentioned above are duplicated in this database.

KODIAKREFS: A subset of the statewide database containing the references
for the source maps of the Kodiak Islands. Linked to the KODIAKUNITS
database through the *source* field.

NNSAKEY: The statewide database that shows the color symbol and label to
be used for each *nsaclass* in the state. Note that these are **not**
the colors and labels used on the KODIAK map (Wilson, in prep.). We have
provided another key database (KODIAKLABELS) that shows the color
symbols and labels appropriate for the Kodiak map. Linked to the
KODIAKUNITS database through the *nsaclass* field. In both cases, the
required ARC/INFO shadesets are not included with this report; please
contact the senior author for information on obtaining this shadeset or
the color definitions. Alternatively, the statewide shadeset can be
downloaded from the following url in the arc-related files section:
http://geopubs.wr.usgs.gov/open-file/of98-133-a/

KODIAKLABELS: This database contains the *nsaclass* and *qclass* codes
tied to the map labels that are used on the Kodiak geologic map (Wilson,
in prep.) and differ from the labels used in NNSAKEY, which are related
to a statewide database assignment. Linked to KODIAKUNITS through
*nsaclass* and *qclass* fields. This database table does not include
labels from units within the included quadrangles but outside the Kodiak
map area.

NSAAGE: The statewide database that provides information to assign
specific ages to geologic units. Linked to the KODIAKUNITS database
through the *nsaclass* field.

NASLITH: The statewide database that provides information to assign
specific lithologies, lithologic form and importance to geologic units.
Linked to the KODIAKUNITS database through the *nsaclass* field.

KODIAKDESCRIP: This database ties *nsaclass* numbers to the unit
descriptions used on the Kodiak map (Wilson, in prep.) and the unit
descriptions from the Central Alaska geologic map (Wilson and others,
1998) compilation for map units that do not appear within the Kodiak map
area. Linked to the KODIAKUNITS database through the *nsaclass* field.

LITHLIST: Database containing all the lithologic terms used in the
lithologic coding -- duplicated here in Appendix 1 of this document.
Linked to the NSALITH database.

LITHFORM: Database containing the lithologic form terms in lithologic
coding of geologic units -- duplicated here in Appendix 1 of this
document. Linked to the NSALITH database.

TIME THESAURUS: Database containing the time terms used in age coding of
geologic units. Linked to the NSAAGE database.

Database structures

# KODIAKUNITS database

The main database for the project is called KODIAKUNITS. Entered into
this database (Table 1) are brief abstracts of the unit descriptions
from each source map, which are then *class*ified into regional or
statewide units. This database is the root for correlations of units,
although not necessarily the final word (more on this later). For
example, Early Cretaceous granodiorite from various maps might get the
same *nsaclass* and therefore be assigned to a single map unit, yet when
drawn to produce particular map, it might be given the same symbol and
color as granite and quartz monzonite of that age (only for that map).
The standard view (called "GSA color") of the database has portals to
three other related databases, NNSAKEY, KODIAKREFS, and NSALITH, which
show the related values in these databases. These databases are linked
through either the *nsaclass* or *source* fields in the KODIAKUNITS
database. The first 7 fields in the database come directly from the
source, each of the other fields is assigned either at the time of entry
into the database or later.

Table 1. KODIAKUNITS field definitions.

  --- -------------- ---------------------------------- -------- ------------
      Field name     Information type                   Field    Links
                                                        type     

  1   *Quadrangle*   1:250,000--scale quadrangle, with  Text     
                     the name fully spelled out. If a            
                     map covers multiple quadrangles,            
                     each quadrangle will have a set of          
                     entries for the appropriate units           
                     from that map in the database.              

  2   *Map unit*     The label given on the source map  Text     
                     for a geologic unit. Some maps do           
                     not use labels; hence a color or            
                     pattern might be entered here. In           
                     other cases, a unit might be                
                     subdivided using overprint                  
                     patterns (such as limestone lenses          
                     in a clastic unit, or areas of              
                     significant lithologic variation).          
                     Where this happens, the variation           
                     is entered in the database as               
                     though it is another geologic               
                     unit.                                       

  3   *Unit name*    The unit name from the source map. Text     
                     If a map is divided in regions,             
                     terranes, or allocthons, etc., or           
                     the unit name explicitly mentions           
                     stratigraphic divisions, then this          
                     information is included in the              
                     unit name (for example, "Lisburne           
                     Group, Kuna Formation", or                  
                     "Greenstone of Venetie Subterrane           
                     of Arctic Alaska Terrane".                  
                     However, in general, we shy away            
                     from using terranes in this                 
                     database.                                   

  4   *Age*          The geologic age of the unit as    Text     
                     given in the source. (Note this is          
                     age and not stratigraphic                   
                     position; convert Upper to Late             
                     and Lower to Early.) In some                
                     cases, the age assignment has been          
                     subsequently revised;                       
                     nevertheless, the age from the              
                     source map is entered..                     
  --- -------------- ---------------------------------- -------- ------------

Table 1. KODIAKUNITS field definitions (cont.).

  ---- --------------- ---------------------------------- ---------- --------------
       Field name      Information type                   Field type Links

  5    *Description*   An abstracted version of the unit  Text       
                       description from the source map.              
                       Focuses on lithology and important            
                       relationships as described on the             
                       source map. Also includes any                 
                       special notes regarding this unit             
                       from the source. This field,                  
                       though of unlimited length is kept            
                       short.                                        

  6    *Fossil*        Brief notes on any fossil control  Text       
                       mentioned on the source map.                  

  7    *Radiometric    Brief notes on radiometric ages.   Text       
       age*                                                          

  8    *Source*        A unique code assigned to each     Text and   KODIAKREFS,
                       source; uses the 2-letter          number     Arc coverage
                       quadrangle code and a three digit  combined   
                       number. By default, 001 is                    
                       reserved for the topographic map              
                       for each quadrangle. Numbers above            
                       100 indicate sources that were not            
                       captured digitally.                           

  9    *Rock class*    General classification: Igneous,   Text,      
                       Sedimentary, Metamorphic,          defined    
                       Unconsolidated, or Melange. For    values     
                       mixed units, the dominant                     
                       category.                                     

  10   *nsamod*        An item to indicate if unit is     Text,      Arc coverage
                       altered, contact metamorphosed, or defined    
                       a queried unit assignment (Tk?     values     
                       versus Tk). (Unit is given same               
                       *nsaclass* code as unmodified                 
                       unit.). Some maps show contact                
                       metamorphosed areas as separate               
                       units, these would be assigned the            
                       *nsaclass* for the appropriate                
                       protolith and then "HFS" selected             
                       as the nsamod value. If only a few            
                       polygons of a unit are altered or             
                       hornfelsed, then the nsamod value             
                       will be set only for those                    
                       specific polygons in the ARC                  
                       coverage.                                     

  11   *Class*         A unique numeric code assigned to  Number     Arc coverage
                       each source unit. (Unique only                
                       within a given quadrangle and                 
                       specific to each source.)                     

  12   *nsaclass*      A regional numeric code assigned   Number     Arc coverage,
                       to like units -- the main key                 NNSAKEY,
                       field in the database                         NSALITH

  13   *Maplabel*      This shows the label used on the   Text       KODIAKLABELS
                       Kodiak map. The alternate field               
                       below it shows the label assigned             
                       if the *nsaclass* value is less               
                       than 500.                                     
  ---- --------------- ---------------------------------- ---------- --------------

Table 1. KODIAKUNITS field definitions (cont.).

  ---- ----------- ---------------------------------- -------- --------------
       Field name  Information type                   Field    Links
                                                      type     

  14   *qclass*    Similar to *nsaclass* that allows  Number   Arc coverage,
                   finer subdivision of Quaternary             KODIAKLABELS
                   geologic units.                             
  ---- ----------- ---------------------------------- -------- --------------

Using the KODIAKUNITS database, a user can determine the disposition of
any geologic unit from any source map that is being used or even
contemplated for use in the statewide database. As such it includes unit
descriptions from maps used for differing purposes or at different
stages of the project. An example is Nelson and other's 1985 geologic
map of the Chugach National Forest, which included parts of the Cordova
quadrangle. Initially, this map was the source for primary geologic data
in the Central Alaska compilation. However, as the project and spatial
database have evolved, the current compilation does not use any part of
this map. Yet, it remains part of the database for archival reasons and
because it is part of the "history" of the development of the present
interpretation of the geology of that region. There is no attempt here
to include every geologic map that has ever been done for the Kodiak
Islands; however, many 1:63,360-scale maps are included because they are
important to the regional story. Regional maps, such as the Beikman
(1980) Geologic map of Alaska are not included. All recent
1:250,000-scale maps are included.

Each source map used in the compilation will have all of its geologic
units entered in this database. If a source map covers more than one
quadrangle, units are entered for all covered quadrangles; however, only
the geologic units that actually appear in a quadrangle will be entered
for a quadrangle. Typically, all units will be entered under the primary
quadrangle and then once digital capture is complete and the digital
file cut into quadrangle specific parts, the units appearing in each
part with be copied to records for that quadrangle in the database. The
reference record for the source map will have an entry for each
quadrangle covered by the map.

Within the database itself, portals in the KODIAKUNITS database look
into the NNSAKEY, NSALITH, NSAAGE, and KODIAKREFS databases, allowing
the user to see the linked data applicable to any record.

# NNSAKEY database

The second most used database is called NNSAKEY (Table 2). This is
analogous to an ARC/INFO lookup table from which labels and colors are
applied to the map. In fact, the primary lookup table used within ARC
for the various Alaska products is derived directly from this database
by importing it (NNSAKEY) into INFO. The primary field in this database
is *nsaclass*, linking it to the KODIAKUNITS database and to the ARC
coverages for each quadrangle. It is here that each unit gets assigned a
symbol (color), overprint pattern, and tentative label to be used on
geologic map products. This database allows control of the symbols and
labels assigned to units and helps to eliminate duplication, except
where desired. The database also includes a description field, which
summarizes the regional unit in a sentence or less and lists the source
maps that contain the unit. This database is not only exported to INFO
to create the lookup table but is also exported to Word to assist in the
classification of units. Portals in the NNSAKEY database look into
KODIAKUNITS, NSAKEY (an old, obsolete database), and back into itself
(NNSAKEY). The portal that looks inward is particularly useful because
it allows a user see instantly what other units have been assigned a
particular symbol. This is important, because although our shadeset
ostensibly has 999 colors, in reality, only about 130 can be
distinguished by eye on plots. (Different plotters have different
capabilities). As a result, a color will get assigned to more than one
unit and overprint patterns must be used to distinguish subsets. This
database is also used to assign duplicate colors and labels to units to
be lumped in map products, but need to be maintained as separate units
in the database. Clearly, other lookup tables, such as KODIAKLABELS
described below, could be and are used to lump units and label in
different ways, depending on the need.

Table 2. NNSAKEY field definitions

  --- --------------- -------------------------------- ---------- ---------------
      Field name      Information type                 Field type Links

  1   *Symbol*        The color number used, derived   Number     NNSAKEY
                      from an ARC/INFO shadeset.                  (self-linked)

  2   *Overprnt*      The pattern number used, also    Number     
                      derived from an ARC/INFO                    
                      shadeset.                                   

  3   *Label*         The map label printed on map     Number     
                      products.                                   

  4   *nsaclass*      A regional numeric code assigned Number     KODIAKUNITS,
                      to like units -- the main key               NSAKEY, Arc
                      field in the database                       coverage

  5   *Description*   Brief (5-10 words) summary of    Text       
                      the unit on a regional basis,               
                      also shows applicable source                
                      maps and overprint pattern                  
                      numbers.                                    
  --- --------------- -------------------------------- ---------- ---------------

# KODIAKLABELS database

Related in concept to the NNSAKEY database, this database provides the
labels and color symbols for units that occur with the Kodiak map area.
The KODIAKUNITS database includes some geologic units that may not occur
on the map, either because they come from source maps we did not use or
the entire units lies outside the map area. These typically will not
show a label in the Maplabel or alternative map label fields. The
primary field in this database is *nsaclass*, linking it to the
KODIAKUNITS database and to the ARC coverages for each quadrangle. This
database also uses the *qclass* field to provide labels for units that
have *nsaclass* codes of less that 500. It is here that each unit gets
assigned a symbol (color), overprint pattern, and tentative label to be
used on geologic map products. This database allows control of the
symbols and labels assigned to units and helps to eliminate duplication,
except where desired. As in the NNSAKEY database, this database is also
used to assign duplicate colors and labels to units to be lumped in map
products, but need to be maintained as separate units in the database.

Table 2a. KODIAKLABELS field definitions

  --- ------------- --------------------------------- ---------- ---------------
      Field name    Information type                  Field type Links

  1   *Symbol*      The color number used, derived    Number     NNSAKEY
                    from an ARC/INFO shadeset.                   (self-linked)

  2   *Overprint*   The pattern number used, also     Number     
                    derived from an ARC/INFO                     
                    shadeset.                                    

  3   *Label*       The map label printed on map      Number     
                    products.                                    
  --- ------------- --------------------------------- ---------- ---------------

Table 2a. KODIAKLABELS field definitions (cont.)

  --- ------------ --------------------------------- ---------- --------------
      Field name   Information type                  Field type Links

  4   *nsaclass*   A regional numeric code assigned  Number     KODIAKUNITS,
                   to like units -- the main key                NSAKEY, Arc
                   field in the database                        coverage

  5   *qclass*     A numeric code assigned to allow  Number     KODIAKUNITS
                   finer subdivisions of Quaternary             
                   geologic units.                              
  --- ------------ --------------------------------- ---------- --------------

# KODIAKREFS database

The KODIAKREFS database (Table 3) contains the reference citation (as
close to USGS style as possible) for each source map and other
publication used. Included in the reference database will be maps that
have been digitized, other publications that result in changes to the
map (say a paper reassigning some rocks from one unit to another or
giving age determinations). It will also list as \"written
communication\" the source of unpublished information responsible for
changes to particular bits of information. There can be up to 999
references for each quadrangle and if we need more, we have room to
expand to over 40,000 per quadrangle. If a map covers multiple
quadrangles, it will be assigned an id for each quadrangle. This
database has a portal into KODIAKUNITS, showing the units from any given
source that is in the KODIAKUNITS database.

Table 3. KODIAKREFS field definitions

  --- ------------- ------------------------------- ---------- --------------
      Field name    Information type                Field type Links

  1   *Source*      The unique code assigned to     Text and   KODIAKUNITS,
                    each source that uses the 2     number     Arc coverage
                    letter quadrangle id and a 3               
                    digit number. This field is                
                    forced to have unique entries              
                    by the database software.                  

  2   *Refnum*      A unique tracking number        Number,    
                    assigned by the database to     auto entry 
                    each reference.                            

  3   *Reference*   The USGS style reference        Text       
                    citation. Also lists written               
                    communications where                       
                    appropriate for modifications              
                    to maps.                                   
  --- ------------- ------------------------------- ---------- --------------

# NSALITH database

The NSALITH database (Table 4) will eventually contain lithologic coding
for each *nsaclass* in the database. It uses a lithologic dictionary
that is contained in special linked databases called LITHLIST and
LITHFORM. It allows for the entry of as many lithologies for a unit as
one desires. This database has a portal into the KODIAKUNITS database,
showing which source maps contain that *nsaclass*.

A unique or special field in this database combines the values of 5
other fields in the database to allow searching of the database at any
level of the lithologic hierarchy without need to be concerned about the
level. Possible searches, for example are for any unit containing
carbonate or for any unit where limestone is a major lithology

A data dictionary has been prepared for use with this database (Appendix
1 and 2, herein), showing the allowed terms in the data.

Table 4. NSALITH field definitions

  ---- ------------- -------------------------------- --------- -------------
       Field name    Information type                 Field     Links
                                                      type      

  1    *nsaclass*    A regional numeric code assigned Number    KODIAKUNITS
                     to like units -- the main key              
                     field in the database                      

  2    *Lith1*       The highest level lithologic     Text,     
                     *class*ification                 value     
                                                      list      

  3    *Lith2*       Next level lithologic            Text,     
                     *class*ification, values are     value     
                     based on the value of *lith1*    list      
                     field                                      

  4    *Lith3*       As above, based on the value of  Text,     
                     *lith2* field                    value     
                                                      list      

  5    *Lith4*       As above, based on the value of  Text,     
                     *lith3* field                    value     
                                                      list      

  6    *Lith5*       As above, based on the value of  Text,     
                     *lith4* field                    value     
                                                      list      

  7    *Form*        Description of form of units,    Text,     
                     value list based on the value of value     
                     *lith1* field.                   list      

  8    *Rank*        Values allowed are: Major,       Text,     
                     Minor, Incidental, and           value     
                     Indeterminate (major).           list      

  9    *Lithology*   This is a field from an earlier  Text      
                     lithologic classification and is           
                     generally not used.                        

  10   *Percent*     Optional field containing an     Number    
                     estimate of the percent of the             
                     unit that the given lithology              
                     represents. This information is            
                     rarely available in Alaska.                

  11   *Comment*     Free form comment field \--      Text      
                     optional                                   

  12   *Record_no*   A unique tracking number         Number,   
                     assigned by the database to each auto      
                     record.                          entry     

  13   *Totallith*   A text string that combines the            
                     information in all of the *lith*           
                     fields, allowing searches based            
                     on any aspect of the lithologic            
                     hierarchy.                                 
  ---- ------------- -------------------------------- --------- -------------

# NSAAGE database

The NSAAGE database (Table 6) is used like NSALITH to assign a uniform
age to each *nsaclass* unit. The fields in it are assigned using a data
dictionary derived from the 1983 DNAG time scale to assigned maximum and
minimum ages to geologic units. The database then creates a field that
has the full definition of the minimum or maximum age of the unit,
allowing searches bases on any part of the time scale. For example, you
could search for units that are at least Paleozoic but no older than
Devonian. Because minimum and maximum numeric ages are also populated in
the databases, any unit can be searched based on a numeric maximum and
minimum.

Note that the ages assigned in this database are for an *nsaclass* unit
and may not necessarily match the assignments made on any given source
map. The assignment of a geologic unit to an *nsaclass* controls the
lithology and the age referenced to that unit by the database. For
example, a source map may call a unit Paleozoic, yet current knowledge
may indicate that unit is actually Permian in age. The KODIAKUNITS
database will show the Paleozoic age as shown in the source whereas the
NSAAGE database with most likely show the Permian age assignment, based
on current knowledge.

Table 6. NSAAGE field definitions

  ---- -------------- -------------- ------------------------------- -------- ----------- --------------- ------------
       Field name     Information                                    Field                Links           
                      type                                           type                                 

  1    *nsaclass*     The regional                                   Number               KODIAKUNITS,    
                      unit code as                                                        Arc coverage    
                      used above                                                                          

  2    *Unit_link*    This field is                                  Text                 (Conterminous   
                      only used in                                                        US databases)   
                      the                                                                                 
                      conterminous                                                                        
                      US and is                                                                           
                      similar in                                                                          
                      some respects                                                                       
                      to *nsaclass*                                                                       

  3    *Min_eon*      The minimum or                                 Text,                                
                      youngest age                                   value                                
                      assignment for                                 list                                 
                      the eon of the                                                                      
                      unit, based on                                                                      
                      geologic                                                                            
                      knowledge.                                                                          

  4    *Min_era*      As above, for                                  Text,                                
                      era                                            value                                
                                                                     list                                 

  5    *Min_period*   As above, for                                  Text,                                
                      period                                         value                                
                                                                     list                                 

  6    *Min_epoch*    As above, for                                  Text,                                
                      epoch                                          value                                
                                                                     list                                 

  7    *Min_age*      As above, for                                  Text,                                
                      age                                            value                                
                                                                     list                                 

  8    *Full_min*     The complete,                                  Text,                                
                      concatenated                                   auto                                 
                      minimum age                                    entry                                
                      assignment.                                                                         

  9    *Max_eon*      The maximum or                                 Text,                                
                      oldest age                                     value                                
                      assignment for                                 list                                 
                      the eon of the                                                                      
                      unit, based on                                                                      
                      geologic                                                                            
                      knowledge.                                                                          

  10   *Max_era*      As above, for                                  Text,                                
                      era                                            value                                
                                                                     list                                 

  11   *Max_period*   As above, for                                  Text,                                
                      period                                         value                                
                                                                     list                                 

  12   *Max_epoch*    As above, for                                  Text,                                
                      epoch                                          value                                
                                                                     list                                 

  13   *Max_age*      As above, for                                  Text,                                
                      age                                            value                                
                                                                     list                                 

  14   *Full_max*     The complete,                                  Text,                                
                      concatenated                                   auto                                 
                      maximum age                                    entry                                
                      assignment.                                                                         

  15   *Type*                        Is the unit age assigned                 Text, value                 
                                     relatively (stratigraphic                list                        
                                     position or fossils) or                  (Relative                   
                                     absolutely (radiometric age).            or                          
                                                                              Absolute)                   
  ---- -------------- -------------- ------------------------------- -------- ----------- --------------- ------------

Table 6. NSAAGE field definitions (cont.)

  ---- ---------------- -------------------------------- --------- ------------
       Field name       Information type                 Field     Links
                                                         type      

  16   *Minimum age*    Text, following the 1983 DNAG    Text,     
                        table for names. Based or        auto      
                        stratigraphic position or fossil entry     
                        control.                                   

  17   *Maximum age*    Text, as above.                  Text,     
                                                         auto      
                                                         entry     

  18   *Min_Ma*         Numeric, either from the DNAG    Number,   
                        table or radiometric             auto      
                        determinations.                  entry     

  19   *Ma_Ma*          Numeric, either from the DNAG    Number,   
                        table or radiometric             auto      
                        determinations.                  entry     

  20   *Age_comments*   Free form comment field \--      Text      
                        optional                                   
  ---- ---------------- -------------------------------- --------- ------------

# KODIAKDESCRIP database

This database ties *nsaclass* numbers to the unit descriptions used on
the Kodiak map (Wilson, in prep.) and the unit description from the
Central Alaska geologic map (Wilson and others, 1998) compilation for
map unit that do not appear within the Kodiak map area.. Linked to the
KODIAKUNITS database through the *nsaclass* field (Table 6). This
database has portals into KODIAKUNITS and NNSAKEY databases.

Table 6. KODIAKDESCRIP field definitions

  --- --------------- -------------------------------- --------- --------------
      Field name      Information type                 Field     Links
                                                       type      

  1   *Label*         Map unit label as published      Text      

  2   *Name*          Map unit name from publication   Text      

  3   *nsaclass*      A regional numeric code assigned Number    KODIAKUNITS,
                      to like units -- the main key              NNSAKEY
                      field in the database                      

  4   *Age*           Assigned age (range)             Text      

  5   *Description*   Full text of unit description    Text      

  6   *Sources*       Specific source for unit         Text      
                      descriptions.                              
  --- --------------- -------------------------------- --------- --------------

# References cited

Capps, S.R., 1937, Kodiak and adjacent islands, Alaska: U.S. Geological
Survey Bulletin 880-C, p. 111-184.

Connelly, William, 1978, Uyak Complex, Kodiak Islands, Alaska: A
Cretaceous subduction complex: Geological Society of America Bulletin,
v. 89, no. 5, p. 755-769.

Connelly, William, and Moore, J.C., 1979, Geologic map of the northwest
side of the Kodiak and adjacent islands, Alaska: U.S. Geological Survey
Miscellaneous Field Studies Map MF-1057, 2 sheets, scale 1:250,000.

Moore, G.W., 1967, Preliminary geologic map of Kodiak Island and
vicinity, Alaska: U.S. Geological Survey Open-File Report 67-161 (271),
1 sheet, scale 1:250,000.

Moore, G.W., 1969, New formations on Kodiak and adjacent islands,
Alaska, *in* Cohee, G.V., Bates, R.G., and Wright, W.B., Changes in
stratigraphic nomenclature by the U.S. Geological Survey 1967: U.S.
Geological Survey Bulletin 1274-A, p. A27-A35.

Moore, J.C., Byrne, Tim, Plumley, P.W., Reid, Mary, Gibbons, Helen, and
Coe, R.S., 1983, Paleogene evolution of the Kodiak Islands, Alaska:
Consequences of ridge-trench interaction in a more southerly latitude:
Tectonics, v. 2, no. 3, p. 265-293.

Wilson, F.H., Dover, J.H., Bradley, D.C., Weber, F.R., Bundtzen, T.K.,
and Haeussler, P.J., 1998, Geologic map of Central (Interior) Alaska:
U.S. Geological Survey Open-File Report 98-133, 3 sheets, scale
1:500,000, 63 p. pamphlet, 13 p. appendix. url:
http://geopubs.wr.usgs.gov/open-file/of98-133-a/

# Appendix 1. Lithologic Data Dictionary

  ---------------- ----------------- ----------------------- ------------------------ ------------------
  Lith1            Lith2             Lith3                   Lith4                    Lith5

  Unconsolidated                                                                      

                   Coarse-detrital                                                    

                                     Boulders                                         

                                     Gravel                                           

                                     Sand                                             

                   Fine-detrital                                                      

                                     Clay                                             

                                     Silt                                             

                   Coral                                                              

                   Marl                                                               

                   Peat                                                               

  Sedimentary                                                                         

                   Clastic                                                            

                                     Mixed-clastic                                    

                                                             Conglomerate-mudstone    

                                                             Conglomerate-sandstone   

                                                             Sandstone-mudstone       

                                                             Siltstone-mudstone       

                                     Conglomerate                                     

                                     Sandstone                                        

                                                             Arenite                  

                                                                                      Calcarenite

                                                             Arkose                   

                                                             Graywacke                

                                     Siltstone                                        

                                     Mudstone                                         

                                                             Claystone                

                                                                                      Bentonite

                                                             Shale                    

                                                                                      Black-shale

                                                                                      Oil-shale

                                                                                      Phosphatic-shale

                                     Sedimentary-breccia                              

                   Carbonate                                                          

                                     Dolostone                                        

                                     Limestone                                        

                                                             Chalk                    

                                                             Coquina                  

                                     Marlstone                                        

                   Chemical                                                           

                                     Banded-iron-formation                            

                                     Barite                                           

                                     Chert                                            

                                     Diatomite                                        
  ---------------- ----------------- ----------------------- ------------------------ ------------------

#  Appendix 1. Lithologic Data Dictionary (cont.)

  ---------------- ------------- ---------------- -------------------------------- -----------------------
  Lith1            Lith2         Lith3            Lith4                            Lith5

  Sedimentary                                                                      

                                 Evaporite                                         

                                                  Anhydrite                        

                                                  Gypsum                           

                                                  Salt                             

                                 Novaculite                                        

                                 Phosphorite                                       

                   Coal                                                            

                                 Anthracite                                        

                                 Bituminous                                        

                                 Lignite                                           

                                 Sub-bituminous                                    

  Igneous                                                                          

                   Plutonic                                                        

                                 Granitic                                          

                                                  Alkalli-feldspar-granite         

                                                                                   Alkali-granite

                                                  Granite                          

                                                                                   Monzogranite

                                                                                   Syenogranite

                                                  Granodiorite                     

                                                  Leucocratic-granitic             

                                                                                   Alaskite

                                                                                   Aplite

                                                                                   Pegmatite

                                                                                   Quartz-rich-granitoid

                                                  Tonalite                         

                                                                                   Trondhjemite

                                 Charnockite                                       

                                 Syenitic                                          

                                                  Alkali-feldspar-syenite          

                                                  Monzonite                        

                                                  Quartz-alkali-feldspar-syenite   

                                                  Quartz-monzonite                 

                                                  Quartz-syenite                   

                                                  Syenite                          

                                 Dioritic                                          

                                                  Diorite                          

                                                  Monzodiorite                     

                                                  Quartz-monzodiorite              

                                                  Quartz-diorite                   
  ---------------- ------------- ---------------- -------------------------------- -----------------------

#  Appendix 1. Lithologic Data Dictionary (cont.)

  ---------------- ------------- ----------------------- ------------------------------ --------------
  Lith1            Lith2         Lith3                   Lith4                          Lith5

  Igneous                                                                               

                   Plutonic                                                             

                                 Gabbroic                                               

                                                         Gabbro                         

                                                                                        Gabbronorite

                                                                                        Norite

                                                                                        Troctolite

                                                         Monzogabbro                    

                                                         Quartz-gabbro                  

                                                         Quartz-monzogabbro             

                                 Anorthosite                                            

                                 Ultramafic                                             

                                                         Hornblendite                   

                                                         Peridotite                     

                                                                                        Dunite

                                                                                        Kimberlite

                                                         Pyroxenite                     

                                 Foidal-syenitic                                        

                                                         Foid-syenite                   

                                                         Cancrinite-syenite             

                                                         Nepheline-syenite              

                                                         Sodalite-syenite               

                                 Foidal-dioritic                                        

                                 Foidal-gabbroic                                        

                                 Foidolite                                              

                                 Melilitic                                              

                                 Intrusive-carbonatite                                  

                   Hypabyssal                                                           

                                 Felsic-hypabyssal                                      

                                                         Hypabyssal-dacite              

                                                         Hypabyssal-felsic-alkaline     

                                                         Hypabyssal-latite              

                                                         Hypabyssal-quartz-latite       

                                                         Hypabyssal-quartz-trachyte     

                                                         Hypabyssal-rhyolite            

                                                         Hypabyssal-trachyte            

                                 Mafic-hypabyssal                                       

                                                         Hypabyssal-andesite            

                                                         Hypabyssal-basalt              

                                                         Hypabyssal-basaltic-andesite   

                                                         Hypabyssal-mafic-alkaline      

                                 Lamprophyre                                            
  ---------------- ------------- ----------------------- ------------------------------ --------------

#  Appendix 1. Lithologic Data Dictionary (cont.)

  ---------------- ----------------- ------------------ ------------------- -------------
  Igneous                                                                   

                   Volcanic                                                 

                                     Alkalic-volcanic                       

                                                        Basanite            

                                                        Foidite             

                                                        Phonolite           

                                     Felsic-volcanic                        

                                                        Dacite              

                                                        Latite              

                                                        Quartz-latite       

                                                        Quartz-trachyte     

                                                        Rhyolite            

                                                        Trachyte            

                                     Mafic-volcanic                         

                                                        Andesite            

                                                        Basalt              

                                                        Basaltic-andesite   

                                     Ultramafic                             

                                                        Komatiite           

                                                        Picrite             

  Metamorphic                                                               

                   Amphibolite                                              

                   Argillite                                                

                   Eclogite                                                 

                   Gneiss                                                   

                                     Orthogneiss                            

                                     Paragneiss                             

                   Granofels                                                

                   Granulite                                                

                   Greenstone                                               

                   Hornfels                                                 

                   Marble                                                   

                   Metasedimentary                                          

                   Metavolcanic                                             

                   Migmatite                                                

                   Phyllite                                                 

                   Quartzite                                                

                   Schist                                                   

                   Serpentinite                                             

                   Skarn                                                    

                   Slate                                                    

  Tectonite                                                                 

                   Cataclastite                                             

                   Mylonite                                                 

                                     Phyllonite                             

                   Melange                                                  

  Water                                                                     

  Ice                                                                       

  Indeterminate                                                             
  ---------------- ----------------- ------------------ ------------------- -------------

#  Appendix 2. Lithform Data Dictionary

  ---------------- ------------------ --- ------------- ------------------------
  **Lith1**        **Lithologic           **Lith1**     **Lithologic form**
                   form**                               

  Unconsolidated                          Igneous       

                   Alluvial                             Batholith

                   Beach                                Diabase

                   Bed                                  Dike or sill

                   Colluvial                            Dome

                   Eolian                               Flow

                   Eolian, loess                        Flow, pillows

                   Estuarine                            Laccolith

                   Flow, mass                           Melange
                   movement                             

                   Fluvial                              Pluton

                   Glacial                              Pyroclastic

                   Glacial, drumlin                     Pyroclastic, air fall

                   Glacial, esker                       Pyroclastic, ash-flow

                   Glacial, outwash                     Pyroclastic, cinder cone

                   Glacial, rock                        Pyroclastic, tuff
                   glacier                              

                   Glacial, till                        Stock or pipe

                   Lacustrine                           Volcaniclastic

                   Landslide                            Volcaniclastic, lahar

                   Mass wasting                         Volcaniclastic, volcanic
                                                        breccia

                   Solifluction           Metamorphic   

                   Swamp                                Amphibolite

                   Tailings                             Amphibolite,
                                                        epidote-amphibolite

                   Terrace                              Eclogite

                   Terrace, marine                      Glaucophane-schist

                   Terrace, stream                      Granulite

  Sedimentary                                           Greenschist

                   Bed                                  Hornfels

                   Calcareous                           Hornfels, biotite

                   Carbonaceous                         Hornfels, hornblende

                   Coquina                              Hornfels, pyroxene

                   Deltaic                              Hornfels, sanidine

                   Dome                                 Pelitic

                   Glauconitic                          Zeolitic
                                                        (prehnite-pumpellyite)

                   Lens                   Tectonite     

                   Melange                              Melange, blocks

                   Olistrostrome                        Melange, matrix

                   Reef                   Water         

                   Tuffaceous                           Lake, stream, or ocean

                                          Ice           

                                                        Mass
  ---------------- ------------------ --- ------------- ------------------------