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Generalized Thermal Maturity Map of Alaska

Frequently anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How should this data set be cited?

   Johnsson, Mark J. , and Howell, David G. , 1996, Generalized Thermal Maturity Map of Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-2494, U.S. Geological Survey, Menlo Park, CA.

   Online Links:

   • <http://geopubs.wr.usgs.gov/dds/dds-54/Map/>

   This is part of the following larger work.

   Johnson, Mark J. , Evans, Kevin R. , and Marshall, Heather A. , 1999, Thermal Maturity of Sedimentary Rocks in Alaska: Digital Resources: U.S. Geological Survey Digital Data Series DDS-54, U.S. Geological Survey, Menlo Park, CA.

   Online Links:

   • <http://geopubs.wr.usgs.gov/dds/dds-54/>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -175.0

   East_Bounding_Coordinate: -130.0

   North_Bounding_Coordinate: 71.5

   South_Bounding_Coordinate: 52.0

3. What does it look like?

   <http://geopubs.wr.usgs.gov/dds/dds-54/Map/outputfiles/MapI2494.pdf> (PDF)

   PDF version of Alaska Thermal Maturity Map

4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 1996

   Currentness_Reference: Publication date of the CD-ROM (1996).

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: map

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Point
      • Complete chain
      • GT-polygon composed of chains

   2. What coordinate system is used to represent geographic features?

      The map projection used is Transverse Mercator.

      Projection parameters:

      Scale_Factor_at_Central_Meridian: 0.926

      Longitude_of_Central_Meridian: -100.00

      Latitude_of_Projection_Origin: 0.00

      False_Easting: 0

      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.025956
      Ordinates (y-coordinates) are specified to the nearest 0.025956
      Planar coordinates are specified in meters

7. How does the data set describe geographic features?

   AKCANBORDER

   Coverage contains a single route in two sections that define the United States-Canadian border. (Source: I-2494)

   LTYPE

   Line Type (Source: I-2494)

   Value	Definition
   national boundary	location of national boundary

   BASE.AAT

   Coverage contains a base map of Alaska produced by vectorizing a scanned image. Lines define coastline, streams, lakes, and bathymetry. Though cleaned up, it contains very small scanning artifacts that are not resolvable at 1:2,500,000, the intended scale of map. (Source: I-2494)

   LTYPE

   Line Type (Source: I-2494)

   Value	Definition
   Base, scan	Scanned base map line
   international boundary	Boundary between Alaska and Canada

   CONTOURS.AAT

   Coverage contains arcs defining contours on the U/M1 map-unit boundary in areas where sufficient well control exists to define that boundary (Colville Basin and Cook Inlet Basin). (Source: I-2494)

   LTYPE

   Line Type (Source: I-2494)

   Value	Definition
   contour, certain	Certain U/M1 contour in meters below sea level
   scratch boundary, certain	Connects the certain contours to create a continuous contour line

   GRATICULE.AAT

   Coverage contains arcs defining latitude-longitude grid lines over map. Many arc segments are needed to make these lines smooth curves. (Source: I-2494)

   LTYPE

   Line type (Source: I-2494)

   Value	Definition
   gridline, certain	Certain latitude-longitude lines over map

   MAIN.PAT

   Principal coverage containing all geologic features (contacts, faults), physiographic features (glaciers, lakes) and thermal-maturity units. (Source: I-2494)

   PTYPE

   Polygon Type (Source: I-2494)

   Value	Definition
   Ig-M	Igneous/metamorphic map unit, certain
   Ig-M?	Igneous/metamorphic map unit, questionable
   S	Supermature map unit, certain
   S?	Supermature map unit, questionable
   O	Overmature map unit, certain
   O?	Overmature map unit, questionable
   M2	Mature 2 map unit, certain
   M2?	Mature 2 map unit, questionable
   M1	Mature 1 map unit, certain
   M1?	Mature 1 map unit, questionable
   U	Undermature map unit, certain
   U?	Undermature map unit, questionable
   ?	Unknown thermal maturity
   Qs	Quaternary sedimentary deposits
   W	Water feature (lakes, oceans)
   G	Glacier
   Unmapped	Areas outside map area (Canada, Russia)

   LTYPE

   Line type (Source: I-2494)

   Value	Definition
   contact, approximately located	Contact whose position is not precisely known
   contact, certain	Observed contact
   contact, concealed	Contact whose position is concealed and inferred
   fault, approximately located	Fault whose position is not precisely known
   fault, certain	Observed fault
   fault, concealed	Fault whose position is concealed and inferred
   fault, detachment, certain	Observed detachment fault
   fault, detachement, concealed	Detachment fault whose position is concealed and inferred
   thrust fault, approximately located	Thrust fault whose position is not precisely known
   thrust fault, certain	Observed thrust fault
   thrust fault, concealed	Thrust fault whose position is concealed and inferred
   water boundary, certain	Observed water boundary
   glacier boundary, certain	Observed glacier boundary
   map boundary, scan	Boundary of scanned map
   scratch boundary, certain	Connects the certain contours to create a continuous contour line

   OUTCROPS.PAT

   A coverage containing points corresponding to all outcrop sample localities. (Source: I-2494)

   CAI

   Real number giving conodont color-alteration-index value at this locality (Source: I-2494)

   Range of values
   Minimum:	0.0
   Maximum:	8.0

   VR

   Real number giving vitrinite-reflectance value at this locality (Source: I-2494)

   Range of values
   Minimum:	0.0
   Maximum:	9.17

   UNIT

   Integer value used to define thermal-maturity map unit for this locality (Source: I-2494)

   Value	Definition
   1	Map Unit "Undermature"
   2	Map Unit "Mature I"
   3	Map Unit "Mature II"
   4	Map Unit "Overmature"
   5	Map Unit "Supermature"

   CMDS

   Character string; a flag used to define continental margin dredge samples. Assigned a null string for all localities except continental margin dredge samples; these are assigned a CMDS value corresponding to map unit for VR or CAI value; used to choose appropriate color of marker symbol in the plot.aml. (Source: I-2494)

   Value	Definition
   Ig-M	Igneous/metamorphic map unit, certain
   Ig-M?	Igneous/metamorphic map unit, questionable
   S	Supermature map unit, certain
   S?	Supermature map unit, questionable
   O	Overmature map unit, certain
   O?	Overmature map unit, questionable
   M2	Mature 2 map unit, certain
   M2?	Mature 2 map unit, questionable
   M1	Mature 1 map unit, certain
   M1?	Mature 1 map unit, questionable
   U	Undermature map unit, certain
   U?	Undermature map unit, questionable
   ?	Unknown thermal maturity
   Qs	Quaternary sedimentary deposits
   W	Water feature (lakes, oceans)
   G	Glacier
   Unmapped	Areas outside map area (Canada, Russia)

   TEXT

   Coverage contains all of map annotation, including names of water features, political and town names, map-unit tags, geologic-feature names, contour labels, and descriptions of thermal-maturity data from selected wells. Contains leaders as arcs. (Source: I-2494)

   LTYPE

   Line type (Source: I-2494)

   Value	Definition
   leader, certain	Definite leader

   TOWNS.PAT

   Coverage contains points showing locations of towns. Database category "PTTYPE" defines three size classes, so that towns of different sizes can be plotted with different symbols. (Source: I-2494)

   PTTYPE

   Character string giving town size, used in plotting different size towns with different symbols. Takes on values small, medium, and large. (Source: I-2494)

   Value	Definition
   small	small town
   medium	medium town
   large	large town

   WELLS1.PAT

   A coverage containing points corresponding to selected wells for which thermal-maturity data were used to constrain contours on U/M1 map-unit boundary surface in the Colville Basin and Cook Inlet Basin. (Source: I-2494)

   WELLNAME

   Character string giving name of well (Source: I-2494)

   SURF

   Vitrinite-reflectance value at the ground surface, extrapolated from subsurface data. (Source: I-2494)

   Range of values
   Minimum:	0.05
   Maximum:	1.52

   WELLS2.PAT

   A coverage containing points corresponding to selected wells for which descriptions of thermal maturity data are provided as callouts in the text coverage. (Source: I-2494)

   WELLNAME

   Character string giving name of well (Source: I-2494)

   SURF

   Vitrinite-reflectance value at the ground surface, extrapolated from subsurface data. (Source: I-2494)

   Range of values
   Minimum:	0.04
   Maximum:	3.76

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Mark J. Johnsson
   • David G. Howell

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Mark Johnsson
   Bryn Mawr College
   Bryn Mawr College
   Bryn Mawr, PA 19010
   USA
   

   johnsson@brynmawr.edu
   

Why was the data set created?

The files in this directory are those that were used to create the Generalized Thermal Maturity Map of Alaska (USGS Miscellaneous Investigations Map I-2494), published in 1996. These files are necessary for importing the map in digital form into a Geographical Information System. Output files in several formats also are included in this directory; these can be used any time a digital version of the complete map is needed.
The map is based, in large part, on the vitrinite-reflectance (VR) and conodont color-alteration-index (CAI) data in USGS Open-File Report 92-409, an updated version of which also is included on this CD-ROM.

How was the data set created?

1. From what previous works were the data drawn?

   Johnsson and Howell, 1996 (source 1 of 2)

   Johnsson, Mark J. , and Howell, David G. , 1996, Thermal Evolution of Sedimentary Basins in Alaska: U.S. Geological Survey Bulletin 2142, U.S. Geological Survey, Denver, CO.

   Online Links:

   • <http://geopubs.wr.usgs.gov/dds/dds-54/Report/Bull2142.pdf>

   Type_of_Source_Media: paper

   Source_Contribution: Data to accompany thermal maturity map

   OFR 92-409 (source 2 of 2)

   Johnsson, M.J., Pawlewicz, M.J., Harris, A.G., and Valin, Z.C., 1992, Vitrinite reflectance and conodont color alteration index data from Alaska: Data to accompany the thermal-maturity map of Alaska: U.S. Geological Survey Open-File Report 92-409.

   Online Links:

   • <http://geopubs.wr.usgs.gov/dds/dds-54/Data/>

   Other_Citation_Details: Revised 1999, packaged as part of DDS-54

   Type_of_Source_Media: paper

   Source_Contribution:

   The "data" directory contains vitrinite reflectance (VR) and conodont color-alteration-index (CAI) data in three formats: a Microsoft Excel (version 5.0) workbook, a set of four ASCII files; and a set of four files in Adobe's PDF format, also accessible through the PDF interface described above. The Excel workbook contains four spreadsheets: one each for VR data from outcrops, VR data from wells, conodont CAI data from outcrops, and conodont color alteration index data from wells. These spreadsheets are neatly formatted and will generally be easier to work with than the ASCII or PDF files, but they do require that the user own a copy of the Microsoft Excel application. The ASCII files are tab-delineated, with the first two records consisting of a title and field labels, respectively. Manipulation of the ASCII files requires a database-management, spreadsheet, or word-processing program capable of reading ASCII files.
   

2. How were the data generated, processed, and modified?

3. What similar or related data should the user be aware of?

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

1. How well have the observations been checked?

2. How accurate are the geographic locations?

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

5. How consistent are the relationships among the observations, including topology?

   The map is based, in large part, on the vitrinite-reflectance (VR) and conodont color-alteration-index (CAI) data in USGS Open-File Report 92-409, an updated version of which also is included on this CD-ROM.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none

Use_Constraints: none

1. Who distributes the data set? (Distributor 1 of 1)
   U.S. Geological Survey Information Services
   Box 25248, Denver Federal Center
   Denver, CO 80255-0286
   USA
   

   1-888-ASK-USGS (voice)
   1-303-202-4693 (FAX)
   

2. What's the catalog number I need to order this data set?

   U.S. Geological Survey Digital Data Series DDS-54

3. What legal disclaimers am I supposed to read?

   This Compact Disc-Read Only Memory (CD-ROM) 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, make 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. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
   Although all data and software published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the U.S. Geological Survey 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.
   Graphical map depictions on this disc are intended to be used within the map scale limits applicable to the source data. Although software enables the user to show images on the disc at various scales, the user is cautioned to refer to the source documentation for the appropriate map scale limitations.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	ARC/INFO export format, Coverages, and Shapefiles (version ARC/INFO version 7.1.1) Size: All files <1 megabyte each
     Network links:	<http://geopubs.wr.usgs.gov/dds/dds-54/Map/>

   • Cost to order the data: none

Who wrote the metadata?

Dates:

Last modified: 27-Jul-2000

Metadata author:

Jennifer Lenz
US Geological Survey
12201 Surise Valley Drive, Mail Stop 918
Reston, VA 20192
USA

703-648-6974 (voice)
703-648-6560 (FAX)
pschweitzer@usgs.gov

Metadata standard:

Content for Digital Geospatial Metadata (FGDC-STD-001-1998)