Geologic map of the Valdez D-1 and D-2 Quadrangles (Mount Wrangell Volcano), Alaska

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Frequently anticipated questions:

What does this data set describe?

Title:
Geologic map of the Valdez D-1 and D-2 Quadrangles (Mount Wrangell Volcano), Alaska
Abstract:
This dataset represents geologic mapping of the Valdez 1:63,360 D-1 and D-2 quadrangles. It is used to create the mapsheet in SIM 3351, which shows bedrock and surficial geology at 1:63,360 scale.
  1. How might this data set be cited?
    Richter, D.H., McGimsey, R.G., Labay, K.A., Lanphere, M.A., Moore, R.B., Nye, C.J., Rosenkrans, D.S., and Winkler, G.R., 2016, Geologic map of the Valdez D-1 and D-2 Quadrangles (Mount Wrangell Volcano), Alaska: U.S. Geological Survey Scientific Investigations Map 3351.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -144.75
    East_Bounding_Coordinate: -144.00
    North_Bounding_Coordinate: 62.00
    South_Bounding_Coordinate: 61.75
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2016
    Currentness_Reference: publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  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.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 6
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -147.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000256
      Ordinates (y-coordinates) are specified to the nearest 0.000256
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.9787.
  7. How does the data set describe geographic features?
    arcs
    Characteristics of the line features in feature class vageol_arc are coded in the attribute table. The attribute table consist of the following items: ARC_CODE and LINE_TYPE. (Source: This dataset)
    ARC_CODE
    ARC_CODE is a numeric short integer field in the attribute table. Values range nonsequentially from 1 to 99. ARC_CODE identifies a stratigraphic boundary, fault, or other linear feature. The ARC_CODE is described by the item LINE_TYPE. (Source: This dataset)
    ValueDefinition
    1CONTACT; SOLID WHERE LOCATION IS ACCURATE
    2GEOMORPHIC CONTACT
    9BOUNDARY OF ALTERED ZONE; HIDDEN LINE
    10THRUST FAULT; SOLID WHERE LOCATION IS ACCURATE; SAW TEETH ON UPPER PLATE
    15ICE CONTACT (GLACIER LIMIT)
    18INTRAFORMATIONAL CONTACT
    28CALDERA MARGIN; ICE COVERED
    30FAULT; UNKNOWN OFFSET; SOLID WHERE LOCATION IS ACCURATE
    99BOUNDING LINE (NEATLINE) OF MAP
    LINE_TYPE
    LINE_TYPE is a text field attribute table. LINE_TYPE describes the type of line. (Source: This dataset)
    ValueDefinition
    CONTACT; SOLID WHERE LOCATION IS ACCURATEStratigraphic contact; location certain
    GEOMORPHIC CONTACTApproximate contact between drift of older glaciation (unit Qog) and deposits of the Copper River Basin (unit Qlg)
    BOUNDARY OF ALTERED ZONE; HIDDEN LINEArc which does not appear on the printed map; Defines boundaries of overprint patterns within the polygon for a geologic unit
    THRUST FAULT; SOLID WHERE LOCATION IS ACCURATE; SAW TEETH ON UPPER PLATEThrust fault; location certain
    ICE CONTACT (GLACIER LIMIT)Glacial boundary
    INTRAFORMATIONAL CONTACTBoundary between polygons of the same unit
    CALDERA MARGIN; ICE COVEREDConcealed caldera margin
    FAULT; UNKNOWN OFFSET; SOLID WHERE LOCATION IS ACCURATEFault; location certain
    BOUNDING LINE (NEATLINE) OF MAPMap boundary
    arcs
    Characteristics of the line features in feature class vadike_arc are coded in the attribute table. The attribute table consists of the following items: ARC_CODE, LINE_TYPE, UNITLABEL, and UNITNAME. (Source: This dataset)
    ARC_CODE
    ARC_CODE is a numeric short integer field in the attribute table. Values range nonsequentially from 1 to 99. ARC_CODE identifies a stratigraphic boundary, fault, or other linear feature. The ARC_CODE is described by the item LINE_TYPE. (Source: This dataset)
    ValueDefinition
    50DIKE
    LINE_TYPE
    LINE_TYPE is a text field attribute table. LINE_TYPE describes the type of line. (Source: This dataset)
    ValueDefinition
    DIKEDike
    UNITLABEL
    ARC_CODE is a numeric short integer field in the attribute table. Values range nonsequentially from 1 to 99. ARC_CODE identifies a stratigraphic boundary, fault, or other linear feature. The ARC_CODE is described by the item LINE_TYPE. (Source: This dataset)
    ValueDefinition
    QciANDESITE DIKES
    UNITNAME
    LINE_TYPE is a text field attribute table. LINE_TYPE describes the type of line. (Source: This dataset)
    ValueDefinition
    ANDESITE DIKESANDESITE DIKES
    polygons
    Characteristics of the polygons in feature class vageol_poly are coded in the attribute table. The attribute table consists of the following items: CLASS, MODIFIER, UNITLABEL (geologic unit label), and UNITNAME (geologic unit name). (Source: This dataset)
    CLASS
    CLASS is a numeric short integer field in the attribute table. Values range nonsequentially from 1 to 42. Every unit listed in the description of map units has a unique CLASS value. Each CLASS value listed below is defined by the information from the UNITLABEL field which contains the geologic unit label if one was assigned and the UNITNAME field which contains the name of the geologic unit. (Source: This dataset)
    ValueDefinition
    1Qaf - ALLUVIUM IN FANS
    2Qc - COLLUVIUM, UNDIVIDED
    3Qd - DACITE FLOW DOME
    5Qdl - ANDESITE FLOWS
    6Qcg - CONGLOMERATE
    7Qba - BASALTIC ANDESITE FLOWS
    8Qdb - DACITE BLOCK AND ASH DEPOSIT
    9Qcl - LAVA FLOWS, PYROCLASTIC DEPOSITS, AND BRECCIAS, UNDIFFERENTIATED
    10Qod - DACITE INTRUSION
    11Qr - ROCK GLACIER DEPOSITS
    12Qda - NADINA VOLCANIC AVALANCHE, LANDSLIDE, AND GLACIAL DEPOSITS, UNDIVIDED
    13Qw - LAVA FLOWS OF THE MOUNT WRANGELL SHIELD
    14Qdc - DACITE DEBRIS APRON
    15Qag - DRIFT OF ALASKAN GLACIATION
    16Qwu - MOUNT WRANGELL LAVAS, UNDIVIDED
    17Qwv - MOUNT WRANGELL VALLEY-FILL AND BASIN LAVAS
    18Qog - DRIFT OF OLDER (WISCONSIN AND OLDER?) GLACIATION
    19Qwe - EARLY LAVA FLOWS OF MOUNT WRANGELL
    20Qcd - ANDESITE-DACITE LAVA DOMES (?) AND BRECCIAS
    21Qyg - DRIFT OF YOUNGER (WISCONSIN) GLACIATION
    22Qa - ALLUVIUM IN STREAMS
    23Qlg - DEPOSITS OF THE COPPER RIVER BASIN, UNDIVIDED
    25Qah - ANDESITE FLOWS
    26Qcf - CHETASLINA VOLCANIC DEBRIS FLOW
    27Qpf - PYROCLASTIC FLOW
    28Qoa - OLDER ALLUVIUM
    30Qwc - PYROCLASTIC DEPOSITS OF THE MOUNT WRANGELL WEST CRATER
    32Jc - CHITINA VALLEY BATHOLITH
    33JPam - HALEY CREEK METAMORPHIC ASSEMBLAGE
    34JTrc - MARINE CLASTIC AND CARBONATE ROCKS, UNDIVIDED
    35Trn - NIKOLAI GREENSTONE
    36Qwp - ANDESITE PLUG OF MOUNT WRANGELL
    38Ks - MARINE SEDIMENTARY ROCKS
    40PPas - SKOLAI GROUP
    41GLACIER
    42Qdi - DACITE PLUGS
    UNITLABEL
    UNITLABEL is a text field in the polygon attribute table which holds the label of the geologic unit. Units queried where uncertain. Each UNITLABEL listed below is defined by the information from the UNITNAME field which provides the name of the unit.
    NOTE: Because of the limitations of common GIS fonts, the letters "Tr"and "Pa" are substituted for the standard symbols for "Triassic" and "Pennsylvanian". (Source: This dataset)
    ValueDefinition
    QafALLUVIUM IN FANS
    QcCOLLUVIUM, UNDIVIDED
    QdDACITE FLOW DOME
    QdlANDESITE FLOWS
    QcgCONGLOMERATE
    QbaBASALTIC ANDESITE FLOWS
    QdbDACITE BLOCK AND ASH DEPOSIT
    QclLAVA FLOWS, PYROCLASTIC DEPOSITS, AND BRECCIAS, UNDIFFERENTIATED
    QodDACITE INTRUSION
    QrROCK GLACIER DEPOSITS
    QdaNADINA VOLCANIC AVALANCHE, LANDSLIDE, AND GLACIAL DEPOSITS, UNDIVIDED
    QwLAVA FLOWS OF THE MOUNT WRANGELL SHIELD
    QdcDACITE DEBRIS APRON
    QagDRIFT OF ALASKAN GLACIATION
    QwuMOUNT WRANGELL LAVAS, UNDIVIDED
    QwvMOUNT WRANGELL VALLEY-FILL AND BASIN LAVAS
    QogDRIFT OF OLDER (WISCONSIN AND OLDER?) GLACIATION
    QweEARLY LAVA FLOWS OF MOUNT WRANGELL
    QcdANDESITE-DACITE LAVA DOMES (?) AND BRECCIAS
    QygDRIFT OF YOUNGER (WISCONSIN) GLACIATION
    QaALLUVIUM IN STREAMS
    QlgDEPOSITS OF THE COPPER RIVER BASIN, UNDIVIDED
    QahANDESITE FLOWS
    QcfCHETASLINA VOLCANIC DEBRIS FLOW
    QpfPYROCLASTIC FLOW
    QoaOLDER ALLUVIUM
    QwcPYROCLASTIC DEPOSITS OF THE MOUNT WRANGELL WEST CRATER
    JcCHITINA VALLEY BATHOLITH
    JPamHALEY CREEK METAMORPHIC ASSEMBLAGE
    JTrcMARINE CLASTIC AND CARBONATE ROCKS, UNDIVIDED
    TrnNIKOLAI GREENSTONE
    QwpANDESITE PLUG OF MOUNT WRANGELL
    KsMARINE SEDIMENTARY ROCKS
    PPasSKOLAI GROUP
    QdiDACITE PLUGS
    MODIFIER
    MODIFIER is a text field in the polygon attribute table. MODIFIER describes additional characteristics of a unit if known. The same attribute can be assigned to multiple units. MODIFIER is also used to place overprint patterns on the map. (Source: This dataset)
    ValueDefinition
    ALTUnit is hydrothermally altered
    QUnit is queried
    points
    Characteristic of the points in feature class vastations are coded in the attribute table. The attribute table consists of the following item: LABEL (Source: This dataset)
    LABEL
    LABEL is a text field in the point attribute table. A number in the label indicates sample has been chemically analyzed. A letter indicates sample has been radiometrically dated. Locations without attributes are other field stations where samples and notes were taken (Source: This dataset) Labels placed on map
    MAP_NUMBER
    MAP_NUMBER is a numeric field in the point attribute table. Identifies sample in table one that has been chemically analyzed. Can be used to join data from table one in table1_chem_analyses to the point locations. (Source: This dataset) Map number from table one.
    MAP_LETTER
    MAP_LETTER is a numeric field in the point attribute table. Identifies sample in table two that has been radiometrically dated. Can be used to join data from table two in table2_radiometric_ages to the point locations. (Source: This dataset) Map letter from table two.
    FIELD_NUMBER
    FIELD_NUMBER is a text field in the point attribute table. Identifies field numbers for samples that are not in tables one or two. These locations are from the field sheets only. (Source: This dataset) Field numbers from field sheets.
    points
    Characteristic of the points in feature class vastruc are coded in the attribute table. The attribute table consists of the following items: STRIKE and DIP (Source: This dataset)
    STRIKE
    STRIKE is a short integer value field in the point attribute table. Every point has a strike value that is used to rotate the inclined bedding symbol. (Source: This dataset)
    Range of values
    Minimum:58
    Maximum:296
    DIP
    DIP is a short integer value field in the point attribute table. Every point has a dip value that is used to show the angle of inclination of the bedding. (Source: This dataset)
    Range of values
    Minimum:0
    Maximum:80
    Entity_and_Attribute_Overview: Trace of detailed geochemistry study by Nye, 1983
    Entity_and_Attribute_Detail_Citation:
    Nye, C.J., 1983, Petrology and geochemistry of Okmok and Wrangell volcanoes, Alaska: Santa Cruz, University of California, Ph.D. dissertation, 208 p.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    This digital coverage was created by Keith Labay, USGS and Jackie McIntire, USGS.
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Robert G. McGimsey
    Geologist
    4210 University Drive
    Anchorage, AK
    USA

    907-786-7432 (voice)
    mcgimsey@usgs.gov

Why was the data set created?

Digital representation of geologic mapping facilitates the presentation and analysis of earth-science data. Digital maps may be displayed at any scale or projection, however the geologic data in this coverage is not intended for use at a scale larger than 1:63,360.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2001 (process 1 of 1)
    The linework was captured by scanning inked mylar overlays or paper maps to create a TIFF that was then heads up digitized. After completion of digitization, the arcs and polygons were attributed using information from the draft map. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Keith Labay
    4210 University Drive
    Anchorage, AK
    USA

    907-786-7410 (voice)
    klabay@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?
    The linework was captured by scanning an inked mylar overlay or paper map to create a TIFF that was then heads up digitized. After completion of digitization features were attributed using information from the draft map. The digital data has been visually checked and the geologic map has undergone technical review.
  2. How accurate are the geographic locations?
    Users of this digital geologic map should respect the intentions of the original mappers and the limitations of the map. This geologic map compilation is intended to be used at a scale of 1:63,360; it is not intended to be used at a more detailed scale.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    These datasets were used to create the map portion of SIM 3351. Text files, tables, graphics, symbolsets, and topography shown on the map sheet are not included.
  5. How consistent are the relationships among the observations, including topology?
    File geodatabase va_geology.gdb contains four feature datasets and three tables.
    geology (feature dataset) - vadike_arc (dikes); vageol_arc (contacts, faults, and other line types); vageol_poly (geologic units); vaunit_anno (unit labels); vaunit_leaders (unit label leaders)
    samples (feature dataset) - vastations (stations locations); vastationsAnno (station map labels)
    section (feature dataset) - nye_section (cross section)
    structure (feature dataset) - vastruc (strike and dip); vastrucAnno (dip labels)
    vageol_lut - Table of symbol numbers and labels for each unique geologic unit
    table1_chem_analyses - Data from table one that can be joined to vastations by map number
    table2_radiometric_ages - Data from table two that can be joined to vastations by map letter

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:
Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from this data.
  1. Who distributes the data set? (Distributor 1 of 1)
    USGS Information Services
    Box 25286
    Denver Federal Center
    Denver, CO
    USA

    303-202-4200 or 1-888-ASK-USGS (voice)
  2. What's the catalog number I need to order this data set? Scientific Investigations Map 3351
  3. What legal disclaimers am I supposed to read?
    Although this data has 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. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data, software, or related materials.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 10-Mar-2016
Last Reviewed: 20-Aug-2014
Metadata author:
U.S. Geological Survey
Attn: Keith Labay
4210 University Drive
Anchorage, AK
USA

907-786-7410 (voice)
klabay@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Generated by mp version 2.9.32 on Thu Mar 10 20:15:21 2016