# YF_README.PDF

# PRELIMINARY INTEGRATED GEOLOGIC MAP DATABASES FOR THE UNITED STATES:

# DIGITAL DATA FOR THE Generalized bedrock GEOLOGIC MAP, YUKON FLATS REGION, EAST-CENTRAL ALASKA

# 

## by

## Digital files prepared by: Keith A. Labay(1), Jesse Crews(2), Frederic H. Wilson(3), Nora Shew(3), and Chad K Hults(3)

## Geologic map by: Alison B. Till (3), Julie A. Dumoulin(3), Jeffrey D. Phillips(4), Richard G. Stanley(5), and Jesse Crews(2)

\(1\) Contractor, SAIC, U.S. Geological Survey, 4200 University Dr.,
Anchorage, AK 99508-4667; (2) Contractor, U.S. Geological Survey, 345
Middlefield Road, Mailstop 969, Menlo Park CA, 94025; (3) U.S.
Geological Survey, 4200 University Dr., Anchorage, AK 99508-4667; (4)
U.S. Geological Survey, P.O. Box 25046, Mailstop 964, Denver, CO
80225-0046; (5) U.S. Geological Survey, 345 Middlefield Road, Mailstop
969, Menlo Park CA, 94025

# DISCLAIMERS

> This report is preliminary and has not been reviewed for conformity
> with U.S. Geological Survey editorial standards or with the North
> American Stratigraphic Code. Any use of trade, product, or firm names
> is for descriptive purposes only and does not imply endorsement by the
> U.S. Government.
>
> This World-Wide-Web publication was prepared by an agency of the
> United States Government. Neither the United States Government nor any
> agency thereof, nor any of their employees, makes any warranty,
> expressed or implied, or assumes any legal liability or responsibility
> for the accuracy, completeness, or usefulness of any information,
> apparatus, product, or process disclosed in this report, or represents
> that its use would not infringe privately owned rights. Reference
> therein to any specific commercial product, process, or service by
> trade name, trademark, manufacturer, or otherwise does not necessarily
> constitute or imply its endorsement, recommendation, or favoring by
> the United States Government or any agency thereof.
>
> Although all data and software published on this Web-site have been
> used by the USGS, no warranty, expressed or implied, is made by the
> USGS as to the accuracy of the data and related materials and (or) the
> functioning of the software. The act of distribution shall not
> constitute any such warranty, and no responsibility is assumed by the
> USGS in the use of this data, software, or related materials.

# PORTABLE DOCUMENT FORMAT (PDF) FILES

> This Web-site contains Portable Document Format (PDF) files for
> viewing and searching documents. In order to view PDF files you will
> need a reader that can translate PDF files. You can download the
> latest version of Adobe Acrobat Reader free via the Internet from the
> Adobe homepage on the World Wide Web at http://www.adobe.com/

# 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. This
regional map is the result of the compilation and reinterpretation of
published and unpublished 1:250,000- and 1:63,360-scale mapping. The map
area encompasses the land area of nine complete 1:250,000-scale
quadrangles and parts of three other quadrangles in east central Alaska.
The metadata associated with each release will provide more detailed
information on sources and appropriate scales for use. Associated
attribute databases accompany the spatial databases of the geology and
are uniformly structured for all maps in the series for ease in
developing regional- and national-scale maps. This 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 mineral occurrence data for the United States.

The Yukon Flats basin (fig. 1) is an areally extensive forested lowland
that contains numerous lakes and streams and marshy areas bordered by
densely vegetated low rolling hills in east central Alaska. The
vegetation is predominantly trees and shrubs in the southern areas and
shrubs and tundra on the northern flank of the basin. The
1:500,000-scale generalized geologic map of the Yukon Flats basin and
its borderlands is intended to show major geologic features that
surround the basin. Geologic (rock) units are generalized to highlight
significant structural boundaries and relationships in order to make the
general geologic setting of the basin more clearly evident and the
subsurface basin geology more easily inferred. The map was compiled
largely from existing geologic maps, most based on field data collected
between 1948 and 1974. However, mapping in the Livengood, Circle, and
parts of the Bettles and Wiseman quadrangles was done in the late 1970's
and the 1980's and data from the Tanana was collected as recently as
2003.

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,* which 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
(ARC/INFO coverage) and can also be found in the text databases of
supplemental attribute data. These fields represent the link 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, more
generally, 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 only to
store the primary map unit information. Fields also in the PAT are
*class*, *label*, *min_age*, and *max_age,* which are more fully
described below. Finally, a field called *lith2* is in the PAT as a
scratch field; no uniform schema has been developed for this field.

![](media/image1.jpeg){width="6.646527777777778in"
height="8.282638888888888in"}

**Figure 1.** Location of the reconnaissance geologic map of the Yukon
Flats showing the geographic setting and associated 1:250,000
quadrangles.

The arc attribute table (AAT) contains 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 map areas for which maps may
have been compiled decades ago. The standardized supplemental attribute
tables record an abstracted map unit description, lithologic and age
information, and references.

All geologic maps on which this compilation is based were published
using the Universal Transverse Mercator projection (UTM; Zones 5, 6, and
7), North American Datum 1927 (NAD-27). 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. Because of the distortions 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 the
more appropriate Albers Equal-area projection. 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/>.

# DATABASE TABLES

In order to manage the textural and coding information related to the
Yukon Flats geologic map, we created a series of related and interlinked
databases. These databases are a subset of the databases being created
and maintained statewide. As provided here, in addition to the native
database format files (.fp5), as well as ".dbf" and ".csv" (comma
separated values) files, we also 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 be can used to guide searches of the coverages seeking
particular sorts of information. By way of background, the PAT files of
the coverages have seven fields in them that correspond to fields in the
.fp5 databases. These fields are *class*, *nsaclass*, *qclass*, *label,
min_ma, max_ma,* and *source*.

Eleven database tables are included here. They are:

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

YFDESCRIP: This database ties *nsaclass* numbers to the more complete
unit descriptions used on the Yukon Flats map. Linked to the YFUNITS
database through the *nsaclass* field.

YFREFS: A subset of the statewide database containing the references for
the source maps of the Yukon Flats map. Linked to the YFUNITS 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 Yukon Flats map. The color symbols and
labels appropriate for the Yukon Flats map have been provided in the
YFDESCRIP database. NNSAKEY is linked to the YFUNITS 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 of (Wilson and others,
1998): <http://geopubs.wr.usgs.gov/open-file/of98-133-a/>.

NSAQKEY: Database is similar to NNSAKEY but it is used to subdivide the
Quaternary surficial deposits by assigning color symbols and labels to
only the Quaternary units. This is not implemented for the Yukon Flats
databases. Linked to YFUNITS through q*class*.

NSALITH: The statewide database that provides information to assign to
geologic units specific rock types, lithologic form, or mode of
occurrence, and relative proportion of the unit that rock type
represents. Linked to the YFUNITS database through the *nsaclass* field.

LITHLIST: Database containing all the lithologic terms (rock types) 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 used for
lithologic coding of geologic units -- duplicated here in Appendix 1 of
this document. Linked to the NSALITH database.

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

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

AGELIST: Database containing the minimum and maximum ages for every Eon,
Era, Period, Epoch, and Age. Linked to the NSAAGE database through *Eon,
Era, Period*, and *Epoch*.

# Runtime application

Included with this data release is a runtime application of the
Filemaker Pro database tables. This application, which only functions
under the Windows operating system, is provided as a zipped directory
that contains the database tables and the necessary files to provide
much of the functionality of the Filemaker Pro software. To use this
application, unzip the supplied zip file, which will create a folder
(directory) containing needed files. Within that folder will be a file
named YFunits Solution.exe. Double click on this file to start the
runtime application. The database tables can be scrolled by clicking on
the "rolodex"-like icon in the upper left corner. Searches can be made
by selecting the "Find mode", found under the "View" tab and typing the
desired search item in the appropriate field on the Find screen. A
complete explanation of the software is not appropriate here, but
experimentation will reveal many capabilities.

# DATABASE STRUCTURES

## YFUNITS database

The main database for the project is called YFUNITS. Entered into this
database (Table 1) are brief abstracts of the unit descriptions from
each source map, which are then classified 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 a 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 in Filemaker Pro
software has portals to three other related databases, NNSAKEY, YFREFS,
and NSALITH, which show the related values in these databases. These
databases are linked through either the *nsaclass* or *source* fields in
the YFUNITS database. The first seven 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.

Using the YFUNITS database, a user can determine the disposition of any
geologic unit from any source map for the map area that is in the
statewide database. As such it includes unit descriptions from maps used
for differing purposes or at different stages of the project.

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. The reference record for the source map will have an
entry for each quadrangle covered by the map.

Table 1. YFUNITS 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*     Label given on the source map for  Text     
                     a geologic unit. Some maps do not           
                     use labels; hence a color or                
                     pattern description would be                
                     entered here. In other cases, a             
                     unit subdivided using an overprint          
                     pattern (such as limestone lenses           
                     in a clastic unit) will have an             
                     entry for each variation.                   
  --- -------------- ---------------------------------- -------- -------------

Table 1. YFUNITS field definitions (cont.)

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

  3   *Unit name*     Map 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 terrane                   
                      terminology is not used in this               
                      database.                                     

  4   *Age*           Geologic age of the unit as given  Text       
                      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                
                      here.                                         

  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*        Unique code assigned to each       Text and   YFREFS, Arc
                      source; uses the 2-letter          number     coverage
                      quadrangle code and a three digit  combined   
                      number. By default, 001 is                    
                      reserved for the topographic map              
                      for each quadrangle.                          

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

Table 1. YFUNITS field definitions (cont.)

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

  10   *Nsamod*     An item to indicate if unit is     Text,     Arc coverage
                    altered, contact metamorphosed, or defined   
                    has a queried unit assignment.     values    
                    Some maps show contact                       
                    metamorphosed areas as separate              
                    units; these units are assigned              
                    the *nsaclass* for the appropriate           
                    protolith and have "HFS" selected            
                    as *nsamod* value. If only a few             
                    polygons of a unit are altered or            
                    contact metamorphosed, then the              
                    *nsamod* value will be set for               
                    those polygons only in the ARC               
                    coverage. Queried units, Tk?                 
                    versus Tk for example, have the              
                    same *nsaclass* codes, but Tk?               
                    will have "Q" selected as *nsamod*           
                    value.                                       

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

  12   *Nsaclass*   Regional numeric code assigned to  Number    Arc coverage,
                    like units -- the main key field             NNSAKEY,
                    in the database.                             NSALITH

  13   *Maplabel*   Label used on the Yukon Flats map. Text      YFDESCRIP

  14   *Qclass*     Similar to *nsaclass*; allows      Number    Arc coverage,
                    finer subdivision of Quaternary              
                    geologic units.                              
  ---- ------------ ---------------------------------- --------- -------------

Within the database itself (see runtime version), portals in the YFUNITS
database provide views into the YFDESCRIP, NNSAKEY, NSALITH, NSAAGE, and
YFREFS database tables, allowing the user to see the linked data
applicable for any record.

## NNSAKEY database

The second most used database is called NNSAKEY (Table 2). This table 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 many derivative 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 YFUNITS 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 it helps to eliminate undesired duplication. The
database also includes a description field, which summarizes the
regional unit in a sentence or less and commonly 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 MS Word to assist in the
classification of units. Portals in the NNSAKEY database provide a view
into YFUNITS and back into itself (NNSAKEY). The portal that looks
inward is particularly useful because it allows a user to 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. As a
result, a color will get assigned to more than one unit and overprint
patterns must be used to distinguish subsets. The ARC/INFO Shadeset used
can be downloaded from the following url in the arc-related files
section of (Wilson and others, 1998):
<http://geopubs.wr.usgs.gov/open-file/of98-133-a/>. The NNSAKEY database
is also used to assign duplicate colors and labels to units that are
lumped in some map products, but otherwise need to be maintained as
separate units in the database.

Table 2. NNSAKEY field definitions

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

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

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

  3   *Label*         Map label printed on map products. Text       

  4   *Nsaclass*      Regional numeric code assigned to  Number     YFUNITS,
                      like units -- the main key field              NSAKEY, Arc
                      in the database.                              coverage

  5   *Description*   Brief (5-10 words) summary of unit Text       
                      on a regional basis.                          
  --- --------------- ---------------------------------- ---------- ---------------

## YFDESCRIP database

This database (Table 3) ties *nsaclass* numbers to the more complete
unit descriptions used on the Yukon Flats map and the unit descriptions
from the Central Alaska geologic map (Wilson and others, 1998)
compilation for map units that do not appear within the Yukon Flats map
area. This table is linked to the YFUNITS database through the
*nsaclass* field and has portals into YFUNITS and NNSAKEY databases. The
ARC/INFO Shadeset used can be downloaded from the following url in the
arc-related files section of (Wilson and others, 1998):
<http://geopubs.wr.usgs.gov/open-file/of98-133-a/> .

Table 3. YFDESCRIP field definitions

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

  1   *Label*         Map unit label as used on the      Text      
                      Yukon Flats map or as published in           
                      Wilson and others (1998).                    

  2   *Name*          Map unit name as used on the Yukon Text      
                      Flats map or as published in                 
                      Wilson and others (1998).                    

  3   *Nsaclass*      Regional numeric code assigned to  Number    YFUNITS,
                      like units -- the main key field             NNSAKEY
                      in the database.                             

  4   *Age*           Assigned age (range).              Text      

  5   *Description*   Full text of unit description as   Text      
                      used on the Yukon Flats map or as            
                      published in Wilson and others               
                      (1998).                                      

  6   *Sources*       Source for unit descriptions (not  Text      
                      the same form the "*source*" in              
                      other database tables).                      
  --- --------------- ---------------------------------- --------- ------------

Table 3. YFDESCRIP field definitions (cont.)

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

  7   *Symbol*     Color number used, derived from an Number    
                   ARC/INFO shadeset. Included here             
                   because a custom color assignment            
                   was used that differs from                   
                   NNSAKEY.                                     

  8   *Overprnt*   Pattern number used, also derived  Number    
                   from an ARC/INFO shadeset.                   
                   Included here because a custom               
                   color assignment was used that               
                   differs from NNSAKEY.                        
  --- ------------ ---------------------------------- --------- ------------

## YFREFS database

The YFREFS database (Table 4) contains the reference citation for each
source map and other publication used. Included in the reference
database will be maps that have been digitized, as well as other
publications that result in changes to the map (for example, a paper
reassigning some rocks from one unit to another or providing new age
determinations). It will also list as \"written commun.\" the source of
unpublished information responsible for changes to particular aspects of
the map. If a source map covers multiple quadrangles, it will be
assigned an identification code for each quadrangle. This database has a
portal into YFUNITS, showing the units from any given source that have
been entered in the YFUNITS database.

Table 4. YFREFS field definitions

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

  1   *Source*      Unique code assigned to each     Text and   YFUNITS, Arc
                    source that uses the two letter  number,    coverage
                    quadrangle id and a three digit  must be    
                    number. This field is forced to  unique     
                    have only unique entries by the             
                    database software.                          

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

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

## NSAQKEY database

The NSAQKEY database (Table 5) is similar to NNSAKEY but it is used to
subdivide the Quaternary surficial deposits by assigning color symbols
and labels to the Quaternary units. The table is used as an ARC/INFO
lookup table to assign the symbols, overprints, and labels to the
surficial deposits.

Table 5. NSAQKEY field definitions

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

  1   *Symbol*     Color number used, derived from an Number     
                   ARC/INFO shadeset.                            

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

  3   *Unit Label* Map label printed on map products. Text       

  4   *Nsaclass*   Regional numeric code assigned to  Number     
                   like units -- the main key field              
                   in the database.                              

  5   *Qclass*     Numeric code used to subdivide     Number     YFUNITS, Arc
                   surficial deposits.                           coverage

  6   *Geologic    Brief (5-10 words) summary of unit Text       
      Unit*        on a regional basis.                          

  7   *Sources*    *Source* code for reference        Text       
                   containing the unit and label of              
                   unit on original source map.                  
  --- ------------ ---------------------------------- ---------- ------------

## NSALITH database

The NSALITH database (Table 6) contains lithologic coding for each
*nsaclass* in the database. It uses a lithologic dictionary that is
contained in special linked database tables called LITHLIST and LITHFORM
(listed in Appendices 1 and 2, herein). It allows for the entry of as
many lithologies for a unit as needed and therefore has a many-to-one
relationship through the *nsaclass* field. This database has a portal
into the YFUNITS database, showing which source maps contain that
*nsaclass*.

A special field in this database combines the values of 5 other fields
in the database. This field allows searching of the database at any
level of the lithologic hierarchy without the need to be concerned about
the level of a given term. Possible searches, for example, are for any
unit containing carbonate or for any unit where limestone is a major
lithology. The *rank* field has four defined values allowed; Major,
meaning greater than or equal to 33 percent; Minor, between 10 and 33
percent; Incidental, less than 10 percent; and Indeterminate (major).
Major is added to the indeterminate category to insure "failsafe" or
inclusive searches for major rock types, as rock types listed in the
indeterminate category could well be major components of a map unit.
These can be eliminated from search results by explicitly omitting
"Indeterminate" from the result.

Table 6. NSALITH field definitions

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

  1   *Nsaclass*   Regional numeric code assigned to   Number    YFUNITS
                   like units -- the main key field in           
                   the database.                                 

  2   *Lith1*      Highest level lithologic            Text,     
                   classification.                     value     
                                                       list      

  3   *Lith2*      Next level lithologic               Text,     
                   classification, values are based on value     
                   the value of *lith1* field.         list      
  --- ------------ ----------------------------------- --------- ----------

Table 6. NSALITH field definitions (cont.)

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

  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, uses  Text,     
                     a value list based on the value of  value     
                     *lith1* field.                      list      

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

  9    *Lithology*   Field from an earlier lithologic    Text      
                     classification and generally not              
                     used.                                         

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

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

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

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

## NSAAGE database

The NSAAGE database table (Table 7) is used like the NSALITH table to
assign a uniform age to each *nsaclass* unit. The fields in it are
assigned using a data dictionary (using the AGELIST database table)
derived from the 1983 DNAG time scale (Geological Society of America,
1983) to assign maximum and minimum ages (using the TIME THESAURUS
database) to geologic units. The database software then creates a field
that has the full definition of the minimum or maximum age of the unit,
allowing searches based on any part of the time scale, similar to the
*totalith* field described above. For example, searches could be for
units that are 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 age as well.

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 YFUNITS database
will list the Paleozoic age as shown in the source whereas the NSAAGE
database will most likely show the Permian age assignment, based on
current knowledge and the assignment of an appropriate *nsaclass*.

Table 7. NSAAGE field definitions

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

  1    *Nsaclass*     Regional unit                                      Number      YFUNITS, Arc
                      code as used                                                   coverage
                      above.                                                         

  2    *Unit_link*    Field only used                                    Text        (Conterminous
                      in the                                                         US databases)
                      conterminous US                                                
                      and is similar in                                              
                      some respects to                                               
                      *nsaclass*                                                     
                      (included for                                                  
                      compatibility                                                  
                      with Conterminous                                              
                      US databases).                                                 

  3    *Min_eon*      Minimum or                                         Text, value 
                      youngest age                                       list        
                      assignment for                                                 
                      the eon of the                                                 
                      unit, based on                                                 
                      current geologic                                               
                      interpretation.                                                

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

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

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

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

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

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

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

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

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

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

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

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

  16   *Cmin_age*                       The most precise minimum age     Text, auto  
                                        coded, derived from the          entry       
                                        *full_min* field.                            

  17   *Cmax_age*                       The most precise maximum age     Text, auto  
                                        coded, derived from the          entry       
                                        *full_max* field.                            
  ---- -------------- ----------------- -------------------------------- ----------- ---------------

Table 7. NSAAGE field definitions (cont.)

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

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

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

  20   Age_comments                 Free form comment field --       Text      
                                    optional.                                  
  ---- -------------- ------------- -------------------------------- --------- ------------

# References cited

Geological Society of America, 1983, Decade of North America Geology
Geologic Time Scale: Geological Society of America Map and Chart series
MC-58, 1 sheet.

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-A, CD-ROM.

# 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
  ---------------- ------------------ --- ------------- ------------------------