Generalized Thermal Maturity Map of Alaska

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What does this data set describe?

Title: Generalized Thermal Maturity Map of Alaska
Abstract:
Alaska is a complex amalgamation of tectonic blocks with diverse histories. Sedimentary basins that are formed on these blocks both before amalgamation and as a result of collisions between them record the tectonic history of this complex region. Thermal-maturity data-indicators of maximum burial temperatures-provide important constraints both on basin evolution and on terrane amalgamation. To help elucidate these relations, and to provide constraints for hydrocarbon assessments, the U.S. Geological survey (USGS) has compilied thermal-maturity data from Alaska for many decades. This report is a digital release of our current understanding of thermal-maturity patters in Alaska.
Supplemental_Information:
The 10 ARC/INFO coverages used to construct the map, together with the directory "INFO" (needed by ARC/INFO to support the coverages), are found in the "coverages" subdirectory. These coverages can be used by any GIS capable of importing files in ARC/INFO format.
Export version of these coverages are found in the subdirectory "exportfiles." These files can be imported into ARC/INFO with the "import" command.
Shapefile versions of 9 of the ARC/INFO coverages are found in the subdirectory "shapefiles." Each shapefile actually consists of three files, with extensions .shp, .shx., and .dbf; all are needed for importation into a GIS supporting the shapefile format.
Inset figures and text, as well as the map title, headers, and latitude-longitude ticks, were created as a separate file. This file is available in Adobe Illustrator 6.0 format (insets.ill) and in Encapsulated PostScript format (insets.eps) in the subdirectory "insetfigures."
The subdirectory "miscfiles" contains many important files needed to use these coverages in ARC/INFO or another GIS.
  1. How might 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:

    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:

  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://pubs.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)
    ValueDefinition
    national boundarylocation 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)
    ValueDefinition
    Base, scanScanned base map line
    international boundaryBoundary 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)
    ValueDefinition
    contour, certainCertain U/M1 contour in meters below sea level
    scratch boundary, certainConnects 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)
    ValueDefinition
    gridline, certainCertain 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)
    ValueDefinition
    Ig-MIgneous/metamorphic map unit, certain
    Ig-M?Igneous/metamorphic map unit, questionable
    SSupermature map unit, certain
    S?Supermature map unit, questionable
    OOvermature map unit, certain
    O?Overmature map unit, questionable
    M2Mature 2 map unit, certain
    M2?Mature 2 map unit, questionable
    M1Mature 1 map unit, certain
    M1?Mature 1 map unit, questionable
    UUndermature map unit, certain
    U?Undermature map unit, questionable
    ?Unknown thermal maturity
    QsQuaternary sedimentary deposits
    WWater feature (lakes, oceans)
    GGlacier
    UnmappedAreas outside map area (Canada, Russia)
    LTYPE
    Line type (Source: I-2494)
    ValueDefinition
    contact, approximately locatedContact whose position is not precisely known
    contact, certainObserved contact
    contact, concealedContact whose position is concealed and inferred
    fault, approximately locatedFault whose position is not precisely known
    fault, certainObserved fault
    fault, concealedFault whose position is concealed and inferred
    fault, detachment, certainObserved detachment fault
    fault, detachement, concealedDetachment fault whose position is concealed and inferred
    thrust fault, approximately locatedThrust fault whose position is not precisely known
    thrust fault, certainObserved thrust fault
    thrust fault, concealedThrust fault whose position is concealed and inferred
    water boundary, certainObserved water boundary
    glacier boundary, certainObserved glacier boundary
    map boundary, scanBoundary of scanned map
    scratch boundary, certainConnects 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)
    ValueDefinition
    1Map Unit "Undermature"
    2Map Unit "Mature I"
    3Map Unit "Mature II"
    4Map Unit "Overmature"
    5Map 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)
    ValueDefinition
    Ig-MIgneous/metamorphic map unit, certain
    Ig-M?Igneous/metamorphic map unit, questionable
    SSupermature map unit, certain
    S?Supermature map unit, questionable
    OOvermature map unit, certain
    O?Overmature map unit, questionable
    M2Mature 2 map unit, certain
    M2?Mature 2 map unit, questionable
    M1Mature 1 map unit, certain
    M1?Mature 1 map unit, questionable
    UUndermature map unit, certain
    U?Undermature map unit, questionable
    ?Unknown thermal maturity
    QsQuaternary sedimentary deposits
    WWater feature (lakes, oceans)
    GGlacier
    UnmappedAreas 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)
    ValueDefinition
    leader, certainDefinite 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)
    ValueDefinition
    smallsmall town
    mediummedium town
    largelarge 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
    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:

    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:

    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?
    Date: 27-Jul-2000 (process 1 of 1)
    Creation of original metadata record Person who carried out this activity:
    Jennifer Lenz
    US Geological Survey
    12201 Surise Valley Drive, Mail Stop 918
    Reston, VA
    USA

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

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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  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
    USA

    1-888-ASK-USGS (voice)
    1-303-202-4693 (FAX)
  2. What's the catalog number I need to order this data set? USGS 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?

Who wrote the metadata?

Dates:
Last modified: 14-Apr-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA
USA

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

This page is <https://geo-nsdi.er.usgs.gov/metadata/map-i/2494/metadata.faq.html>
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