Digital database for Geologic Map of Mount Gareloi, Gareloi Island, Alaska

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Frequently anticipated questions:

What does this data set describe?

Title:
Digital database for Geologic Map of Mount Gareloi, Gareloi Island, Alaska
Abstract:
This digital publication contains the geologic map information used to publish the U.S. Geological Survey Scientific Investigations Map 3145 (Coombs and others, 2012), which depicts the geology of Mount Gareloi, Gareloi Island, Alaska.
Supplemental_Information:
All the geologic map information used to publish the U.S. Geological Survey Scientific Investigations Map 3145 is contained in this digital database. The database includes feature classes that depict geologic map units and the contacts between them, geologic structures, and sample locations. The feature dataset GarGeology contains the feature classes GarGeoLines, GarGeoPoints, GarGeoPolys, GarStructure, GarStations, GarGeoPolysAnno, and All_samplesAnno. Additionally, the geodatabase includes a nonspatial table of geochemistry data, GarGeochem.
NOTE: The GIS database for this map has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.All the geologic map information used to publish the U.S.
  1. How should this data set be cited?

    Michelle L Coombs, Robert G. McGimsey, Brandon L. Browne, 2012, Digital database for Geologic Map of Mount Gareloi, Gareloi Island, Alaska: U.S. Geological Survey Scientific Investigations Map, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -178.880538
    East_Bounding_Coordinate: -178.721018
    North_Bounding_Coordinate: 51.839120
    South_Bounding_Coordinate: 51.741428

  3. What does it look like?

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

    Calendar_Date: 2003
    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. It contains the following vector data types (SDTS terminology):

      • String (158)
      • G-polygon (77)
      • String (258)
      • Entity point (153)
      • G-polygon (75)
      • G-polygon (115)
      • Entity point (80)
      • G-polygon (115)
      • Entity point (80)
      • G-polygon (77)

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 1
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -177.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000005
      Ordinates (y-coordinates) are specified to the nearest 0.000005
      Planar coordinates are specified in meters

      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Resolution: 0.000010
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    GarGeoLines
    Locations of contacts mapped between geologic rock units. (Source: Author)

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Linetype
    The nature and scientific confidence of the contact. (Source: Author)

    ValueDefinition
    contact, accurate 
    contact, inferred 
    water boundary 

    SHAPE_Length
    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    GarGeoPolys
    Polygon feature class of map units. (Source: Author)

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Unit
    Geologic map unit abbreviation. (Source: Author)

    ValueDefinition
    d29Debris-flow deposits (1929)
    l29Latite lava flows (1929)
    p29Pyroclastic apron (1929)
    t29Trachyte lava flows (1929)
    l87Lava flow (1987)
    bBeach deposits
    dFluid debris-flow deposits
    dvViscous debris-flow deposits (Holocene)
    seeShoshonite of the early edifice (Pleistocene)
    icePerennial ice/snow
    anfAndesite of the north flank (Pleistocene)
    pefLithic pyroclastic flow deposits of the east flank (Holocene)
    pnpAgglutinate, spatter, and pyroclastic deposits of North Peak (Holocene - recent)
    lnpuUndivided lavas of North Peak (Holocene)
    sefShoshonite lavas of the east flank (Late Holocene)
    lnpSheet lava field of the north flank (Holocene)
    snwShoshonite lavas of the northwest flank (Late Holocene)
    cspAltered crater rocks of South Peak (Holocene)
    sspShoshonite lava-flow field of the South Peak crater (Historical - 1950-1980)
    ssfShoshonite dome of the south flank (Pleistocene)
    dsfDebris-flow deposits of the south flank (Historical - 1946-1980)
    aspAndesite of South Peak (late Holocene?)
    lspLavas of South Peak (Holocene)
    pspPyroclastic deposits of South Peak (Holocene)

    SHAPE_Length
    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    SHAPE_Area
    Area of feature in internal units squared. (Source: ESRI)

    Positive real numbers that are automatically generated.

    Symbol
    Identifier for a fill symbol in an ArcGIS style file. (Source: Author)

    Anno_3_41
    Relationship class defining relationsip between GarGeoPolysAnno and GarGeoPolys. (Source: Author)

    GarStructure
    Line feature class of geomorphic and structural features. (Source: Author)

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Linetype
    Nature and scientific confidence of the mapped linear feature. (Source: Author)

    ValueDefinition
    crater rim, certain 
    dike, approximately located 
    ground crack 
    internal flow boundary 
    landslide scarp 
    normal fault, queried 

    SHAPE_Length
    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    GarStations
    Locations of field stations occupied during the mapping effort. (Source: Author)

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    GEOLOGIST
    Name of the geologist who established the station. (Source: Author)

    ValueDefinition
    Browne, B. 
    Coombs, M. 
    McGimsey, G. 

    DATE_
    Date of occupation. (Source: Author)

    STATIONID
    Identifier in the form GG#, where GG is a two letter abbreviation for the geologist and # is a (roughly) sequential number. (Source: Author)

    SAMPLEID
    Identifier in the form YYVVGG#, where YY is a two number year value, VV is a two letter abbreviation for the volcano, GG is a two letter abbreviation for the geologist, and # is a (roughly) sequential number. (Source: Author)

    ELEVATION_FT
    Elevation of the station in feet; usually collected from GPS and not verified against another source. (Source: Author)

    SAMPLETYPE
    Simple rock type description of the hand sample. (Source: Author)

    ValueDefinition
    ash fall 
    bomb 
    bomb/lithic 
    bulk pf (reworked) 
    clay 
    gabbro bomb 
    lava 
    lava bomb 
    pf 
    pf bulk sample 
    pumice 
    pumice fall 
    pyroclastic 
    pyroclastic flow deposit 
    scoria 
    scoria bomb 
    scoria fall 
    scoria lapilli 
    soil 
    stream sediment 
    surge/phreatic deposit 
    tephra 
    xenolith bomb 

    DESCRIPTION
    Longer description of the hand sample, location, geology, etc. (Source: Author)

    UNIT
    Map unit from which the sample was collected., (Source: Author)

    AR_AR
    Ar39/ Ar40 age of the sample. (Source: Author)

    CHEMSPLIT
    True/false whether there are geochemistry results for this sample. (Source: Author)

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    GarGeoPolysAnno
    Feature-linked annotation class used to label features in GarGeoPolys. Automatically by ArcGIS. (Source: Author)

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    FeatureID

    ZOrder

    AnnotationClassID

    Element

    SymbolID

    Status

    TextString

    FontName

    FontSize

    Bold

    Italic

    Underline

    VerticalAlignment

    HorizontalAlignment

    XOffset

    YOffset

    Angle

    FontLeading

    WordSpacing

    CharacterWidth

    CharacterSpacing

    FlipAngle

    Override

    SHAPE_Length
    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    SHAPE_Area
    Area of feature in internal units squared. (Source: ESRI)

    Positive real numbers that are automatically generated.

    All_samplesAnno
    Feature-linked annotation feature class used to label features in GarStation. Automatically by ArcGIS (Source: Author)

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    FeatureID
    ArcGIS-managed field. (Source: Author)

    ZOrder
    ArcGIS-managed field. (Source: Author)

    AnnotationClassID
    ArcGIS-managed field. (Source: Author)

    Element
    ArcGIS-managed field. (Source: Author)

    SymbolID
    ArcGIS-managed field. (Source: Author)

    Status
    ArcGIS-managed field. (Source: Author)

    TextString
    ArcGIS-managed field. (Source: Author)

    FontName
    ArcGIS-managed field. (Source: Author)

    FontSize
    ArcGIS-managed field. (Source: Author)

    Bold
    ArcGIS-managed field. (Source: Author)

    Italic
    ArcGIS-managed field. (Source: Author)

    Underline
    ArcGIS-managed field. (Source: Author)

    VerticalAlignment
    ArcGIS-managed field. (Source: Author)

    HorizontalAlignment
    ArcGIS-managed field. (Source: Author)

    XOffset
    ArcGIS-managed field. (Source: Author)

    YOffset
    ArcGIS-managed field. (Source: Author)

    Angle
    ArcGIS-managed field. (Source: Author)

    FontLeading
    ArcGIS-managed field. (Source: Author)

    WordSpacing
    ArcGIS-managed field. (Source: Author)

    CharacterWidth
    ArcGIS-managed field. (Source: Author)

    CharacterSpacing
    ArcGIS-managed field. (Source: Author)

    FlipAngle
    ArcGIS-managed field. (Source: Author)

    Override
    ArcGIS-managed field. (Source: Author)

    SHAPE_Length
    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    SHAPE_Area
    Area of feature in internal units squared. (Source: ESRI)

    Positive real numbers that are automatically generated.

    Anno_39_42
    Relationship class defining a relationship between annotation in All_samplesAnno and GarStations. (Source: Author)

    GarGeochem
    Whole-rock major-element-oxide (in wt percent) and trace-element (in ppm) abundances for analyzed Gareloi samples. (Source: Author)

    SampleID
    Unique sample identifier, usually the station ID, some with a letter suffix. (Source: Author)

    Unit
    The map unit from which the sample was collected. (Source: Author)

    UTM_East
    Easting in UTM Zone 1, WGS84 (Source: Author)

    UTM_North
    Northing in UTM Zone 1, WGS84 (Source: Author)

    Sample_type
    Material from which the hand sample was collected. (Source: Author)

    Field_desc
    Brief description of the sample location and/or the sample itself. (Source: Author)

    Thinsxn_notes
    Brief description of the mineralogy as seen in a thin section from the sample. (Source: Author)

    SiO2

    TiO2

    Al2O3

    FeO

    MnO

    MgO

    CaO

    Na2O

    K2O

    P2O5

    Ni

    Cr

    Sc

    V

    Ba

    Rb

    Sr

    Zr

    Y

    Nb

    Ga

    Cu

    Zn

    Pb

    La

    Ce

    Th

    Ce1

    Pr

    Nd

    Sm

    Eu

    Gd

    Tb

    Dy

    Ho

    Er

    Tm

    Yb

    Lu

    Ba1

    Th1

    Nb1

    Y1

    Hf

    Ta

    U

    Pb1

    Rb1

    Cs

    Sr1

    Sc1

    Zr1

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Entity_and_Attribute_Overview:
    This metatdata file for the GarGeology.mdb geodatabase was written to provide an overview for the complete database in its form as an ESRI ArcGIS 9.3 personal geodatabase. For more informative descriptions of the attributes please see the metadata embedded within each feature class (using ArcCatalog) or the metadata file associated with each shapefile in the shapefile version of this geodatabase. Note that if you are using the shapefile versions of the datasets contained within the geodatabase (1 field names are truncated to 10 characters and (2 only the descriptions of feature classes in this file will be relevant. That is, relationships between feature classes, as they exist as objects within the geodatabase cannot be exported to any format immediately usable with shapefiles.
    Spatial database objects in the geodatabase are organized within a single feature dataset called GarGeology. There are four geology feature classes, GarGeoLines, GarGeoPolys, GarStations, and GarStructure; a topology relationship class, GarGeology_topology; two annotation feature classes, All_samplesAnno and GarGeoPolysAnno; and two annotation relationship classes, Anno_39_42 and Anno_3_41.
    There is one nonspatial table in the geodatabase, GarGeochem, which can be joined to GarStations based on the common key field, SAMPLEID.
    GarGeoLines holds all geologic line features. LINETYPE is the one non-ArcGIS-managed field and stores a classifier that is also used as the symbol name in an ESRI style file.
    GarGeoPolys holds all geologic map unit polygons. The field UNIT carries abbreviations of the map unit name and SYMBOL is a reference to a numerical symbol name in an ESRI style file.
    GarStations holds points representing field locations occupied during the mapping campaign. GEOLOGIST is the name of the mapper or geologist. DATE_ carries the date of occupation. STATIONID is a unique identifier for the station in form of "GG##" where GG is a two letter abbreviation of the geologist's name and ## is a zero-padded sequential number. SAMPLEID is a unique identifier of the a sample collected at the station in the form of YYGGG##L where YY is the last two characters of the year, GGG is a three letter abbreviation of the geologist's name, ## is the same number found in the parent stationid, and L is a sequential alphabetical character used in the case of multiple samples taken at a single station. ELEVATION_FT is the elevation of the station in feet as determined by recreational-grade GPS units or base map contour. SAMPLETYPE is classifier for the sample material, if collected. DESCRIPTION is a description of the station location, sample, or both. UNIT is the map unit in which the station is located or from which the sample was collected. AR_AR is the argon40/argon39 age of the sample in thousands of years, if determined. CHEMSLPIT indicates, T = True, if a chemistry analysis was performed. Results are in GarGeochem (see below).
    GarStructure is feature class of linear structural features such as ground cracks or internal flow boundaries. LINETYPE carries a single value used as a classifier and a symbol name relating to an ESRI style file.
    GarGeologyTopology is a topology relationship class between GarGeoLines and GarGeoPolys used for the creation of features in GarGeoPolys.
    The two annotation feature classes and the associated relationship classes were created in ArcMap using default settings and all fields are managed automatically by ArcGIS.
    GarGeochem is a nonspatial table of whole-rock major-element-oxide (in wt percent) and trace-element (in ppm) abundances for analyzed samples. SAMPLEID is a key field with SampleID in GarStations and can be used for building joins or relationships. UNIT is the map unit from which the sample was collected. UTM_EAST is the easting in UTM Zone 1, WGS84. UTM_NORTH is the northing in UTM Zone 1, WGS84
    Entity_and_Attribute_Detail_Citation: This report.

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?

    U.S. Geological Survey, Alaska Volcano Observatory

  3. To whom should users address questions about the data?

    U.S. Geological Survey, Alaska Volcano Observatory
    Attn: Michelle Coombs
    Research Geologist
    4210 University Drive
    Anchorage, AK
    USA

    907-786-7403 (voice)
    907-786-7425 (FAX)
    mcoombs@usgs.gov

Why was the data set created?

This database was constructed in order to produce a geologic map as a basis for understanding volcanic processes and hazards of Mount Gareloi.

How was the data set created?

  1. From what previous works were the data drawn?

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

    (process 1 of 2)
    Geologic lines representing the contacts between map units and other linear geologic features were mapped in the field in 2003 by Coombs, Browne, and McGimsey and digitized in 2005 by Coombs. Refinement of field contacts was achieved by digitzing contacts from digital satellite data provided by the US Geological Survey. Map unit polygons were created from the lines and points with unit attributes. Metadata were created only prior to release.

    Date: 17-May-2010 (process 2 of 2)
    Dataset copied.

    Data sources used in this process:

    • D:\Workspace\AVO\Pubs\Gareloi\GarGeology.mdb

  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?

    Well-located data items are intended to have a horizontal positional accuracy better than 25 meters on the ground. Most lines were digitized from an orthophoto base with a cellsize of 0.5 m. The general positional accuracy of each line in the database is indicated qualitatively within the Linetype field in the Contacts feature class. Points in the database are located using hand-held GPS are are generally accurate to within 10 m.

  3. How accurate are the heights or depths?

    Vertical positional data are recorded for some stations and samples and were obtained using hand-held GPS units.

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

    Data set has been visually inspected. All data produced strives to meet National Mapping Accuracy Standards (NMAS).

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

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:
SPATIAL RESOLUTION-Uses of this digital geologic map should not violate the spatial resolution of the data. Although the digital form of the data removes the constraint imposed by the scale of a paper map, the detail and accuracy inherent in map scale are also present in the digital data. The fact that this database was edited for a scale of 1:24,000 means that higher resolution information is not present in the dataset. Plotting at scales larger than 1:24,000 will not yield greater real detail, although it may reveal fine-scale irregularities below the intended resolution of the database. Similarly, where this database is used in combination with other data of higher resolution, the resolution of the combined output will be limited by the lower resolution of these data.

  1. Who distributes the data set?[Distributor contact information not provided.]

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 05-Aug-2009
Metadata author:
U.S. Geological Surve
Attn: Evan Thoms
Geologist
4210 University Drive
Anchorage, AK
U.S.A.

907-786-7409 (voice)
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.28 on Thu Jan 8 17:12:44 2015