North Carolina Geology

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Frequently-anticipated questions:

What does this data set describe?

Title: North Carolina Geology
Abstract:
The North Carolina Department of Environment and Natural Resources, Division of Land Resources, NC Geological Survey, in cooperation with the North Carolina Center for Geographic Information and Analysis, developed the GIS data set version of the Geology of North Carolina. The data represents the digital equivalent of the official State Geology map (1:500,000- scale), but was digitized from (1:250,000-scale) base maps. There are two additional data sets which accompany this layer, dikes and structures. These should be used together with the Geology formations layer. All three data sets come together. (Refer to the cross references section for more detail on the dikes and structures).
Supplemental_Information:
These data includes three Feature Classes: geol250_polygons, which contains geologic formations; geol250_dikes, which contains diabase dikes; and geol250_structuress, which contains geologic structures (faults, folds, scarps, contacts, and structural symbols).
To purchase a hardcopy of this data layer (the official 1985 NC State Geologic Map, shown at a 1:500,000 scale), contact: NC Geologic Survey Mail Service Center 1612 Raleigh, NC 27699-1612 (919) 733-2423 Hard copy plots (1:500,000) from the digital files are available for $12.00. The published, printed map is out-of-print and no longer available. Call to confirm availability and price.
These data correspond to the DOT county boundary file. Other county boundary files may not be compatible with this layer.
Use the ESRI layer file = geol250_polygons_92.lyr for proper symbolization as depicted on the published 1985 map; link to field 'GEOCODE'. This layer file was created using ArcGIS 9.2. If this file does not accompany this dataset, contact the NC Geological Survey for a copy.
Revisions and updates to this layer include: 5.) October 2007 = Updated minor coding errors in polygon attribute table. Layer file created for symbology to match as closely as possible the published 1985 printed Geologic Map of North Carolina. 4.) September 2007 = conversion from ESRI Arc/Info Coverage to ESRI Personal Geodatabase. this was done in an effort to capture and store all pertinent data in this dataset. 3.) filename: geol250ed The July 1999 update to this layer fixed digitization errors in the 1998 and 1993 revisions. The July 1999 update includes additional attributes and an five auxiliary text files which include information from the hard copy 1985 Geologic Map. 2.) filename: geol2501298 The December 1998 update to this layer consisted of projecting the data from NAD27 datum, State Plane projection, units of measure feet TO: NAD83 DATUM, State Plane PROJECTION, UNITS OF MEASURE METERS. This was done to comply with the NC Geographic Information Coordinating Council's "Statement of Direction for North Carolina Corporate Geographic Database Horizontal Reference, Datum and Unit of Measure". This reprojecting was done in various ways depending on the data type and content. Vector data was projected using the 'project' command in ESRI's Arc software and topology was cleaned and built based on coverage needs. Raster data was projected using ESRI's Grid module and various steps as applicable. 1.)geol25093 - This represents the 1993 version which contains the following correction. In the spring of 1993, a geologic formation (ZYba, Amphibolite) in Macon County was added in order to correct the digital file. This formation had been omitted in the original digitization. The file containing the omitted information has been deleted. The associated files names are: geol250d for dikes and geol250f for faults.
  1. How should this data set be cited?

    North Carolina Geological Survey (NCGS), 200710, North Carolina Geology: NCGS, Raleigh, North Carolina.

    Online Links:

    Other_Citation_Details: Source data available from the NCGS

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -84.422473
    East_Bounding_Coordinate: -75.418541
    North_Bounding_Coordinate: 36.617435
    South_Bounding_Coordinate: 33.732442

  3. What does it look like?

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

    Calendar_Date: 1986
    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):

      • G-polygon (1845)
      • GT-polygon composed of chains (1848)
      • Node, planar graph (2864)
      • Area point (1848)

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

      Grid_Coordinate_System_Name: State Plane Coordinate System 1983
      State_Plane_Coordinate_System:
      SPCS_Zone_Identifier: 3200
      Lambert_Conformal_Conic:
      Standard_Parallel: 34.333333
      Standard_Parallel: 36.166667
      Longitude_of_Central_Meridian: -79.000000
      Latitude_of_Projection_Origin: 33.750000
      False_Easting: 609601.220000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000001
      Ordinates (y-coordinates) are specified to the nearest 0.000001
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: National Geodetic Vertical Datum of 1929
      Altitude_Resolution: 0.000100
      Altitude_Distance_Units: feet
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    geol250_polygons
    Polygon Attribute Table (Source: None)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    GEOL250_ID
    User Identifier, unique number for each polygon (Source: NCGS)

    Internal tracking number

    GEOCODE
    Abbreviation for Geologic Formation or unit name (Source: NCGS)

    ValueDefinition
    Geologic Rock unit abbreviationsRock unit abbreviations

    BELT
    Geologic belt used in 1985 paper map legend (Source: NCGS)

    ValueDefinition
    Geologic BeltsGeologic Belt names

    BELT2
    Major geologic belt (Source: User Defined)

    ValueDefinition
    Major Geologic Beltlist of major geologic belt

    GROUP_
    Stratigraphic or lithologic group (Source: NCGS)

    ValueDefinition
    Stratigraphic or lithologic groupStratigraphic or lithologic group

    TYPE
    Rock type from legend (Source: User Defined)

    ValueDefinition
    Rock type from legendRock type from legend

    FORMATION
    Stratigraphic or lithologic name of geologic unit (Source: NCGS)

    ValueDefinition
    Stratigraphic or lithologic name of geologic unitStratigraphic or lithologic name of geologic unit

    EON
    Geologic eon (age) designation (Source: Geological Time Table, 1988, Haq, B.U., van Eysinga, F.W.B., compilers, 5th Edition, Amsterdam, Elsevier.)

    ValueDefinition
    Geologic eonGeologic eon

    ERA
    Geologic ERA (age) (Source: Geological Time Table, 1988, Haq, B.U., van Eysinga, F.W.B., compilers, 5th Edition, Amsterdam, Elsevier.)

    ValueDefinition
    Geologic ERAGeologic ERA

    PERIOD
    Geologic period (Source: Geological Time Table, 1988, Haq, B.U., van Eysinga, F.W.B., compilers, 5th Edition, Amsterdam, Elsevier.)

    ValueDefinition
    Geologic periodGeologic period

    ABS_AGE
    Absolute age in millions of years (if known from radiometric date) (Source: Various sources, see age_ref.dbf)

    Absolute age in millions of years (if known from radiometric date)

    REF_NUM
    Reference Number - cross-reference number for map age references, as shown on the 1985 Geologic Map of North Carolina. This field cannot be related to age_ref.dbf, however, the numbers in the ref_num field in geol250_polygons correspond to the numbers in age_ref.dbf. (Source: NCGS)

    Reference number

    LEG_NUM
    Relative order of geologic unit descriptions in legend within "BELT" designation (Source: NCGS)

    Relative order of geologic unit descriptions in legend within "BELT" designation

    Shape_Leng
    Perimeter of polygons, in map units (Source: ESRI)

    ValueDefinition
    Shape_LengPerimeter of polygon, in internal (map) units

    Shape_Area
    Area of feature in internal units squared; supercedes AREA field (not deletable) (Source: ESRI)

    Positive real numbers that are automatically generated.

    DESCRIP_1
    Rock or unit description, field 1 of 3 (Source: NCGS)

    Unit descriptions for geologic formations and informal units.

    DESCRIP_2
    Rock or unit description, field 2 of 3 (if needed) (Source: NCGS)

    Unit descriptions for geologic formations and informal units.

    DESCRIP_3
    Rock or unit description, field 3 of 3 (if needed) (Source: NCGS)

    Unit descriptions for geologic formations and informal units.

    Entity_and_Attribute_Overview:
    A polygon coverage depicting the official geologic map of North Carolina (1985) as published by the NC Geological Survey and the US Geological Survey.
    Entity_and_Attribute_Detail_Citation:
    Refer to: "Geologic Map of North Carolina, 1985" for a hardcopy version, and detailed descriptions of the Major Litho-Tectonic Features, Geologic Time Scale, and Paleozoic Metamorphic Facies.

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?

    NC DENR - Division of Land Resources Director - NC Geological Survey NC OITS - CGIA

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

    North Carolina Geologica Survey (NCGS)
    c/o Kenneth B. Taylor
    Chief Geologist
    1612 Mail Service Center
    Raleigh, NC 27699
    U.S.A

    919-733-2423 (voice)
    919-733-0900 (FAX)
    kenneth.b.taylor@ncmail.net

    Hours_of_Service: 9 a.m. - 5 p.m.

Why was the data set created?

This data was created to assist governmental agencies and others in making resource management decisions through use of a Geographic Information System (GIS).

How was the data set created?

  1. From what previous works were the data drawn?

    None (source 1 of 2)
    NC DENR-Division of Land Resour, NC Geological Survey, 1999, Geology - North Carolina (1;250,000): NC DENR-Division of Land Resources, NC Geological Survey, Raleigh, North Carolina.

    Other_Citation_Details: This data set contains 3 coverages and 5 text files
    Type_of_Source_Media: Mylar
    Source_Scale_Denominator: 250000
    Source_Contribution:
    Data depicting the official geology of North Carolina, on mylar stable bases. Correction of digitization errors and complete attribution.

    None (source 2 of 2)
    NC Center for Geographic Information and Analysis, 1993, Geology - North Carolina (1;250,000): NC Center for Geographic Information and Analysis, Raleigh, North Carolina.

    Other_Citation_Details: This data set is part of the NC Corporate Geographic Database
    Type_of_Source_Media: Mylar
    Source_Scale_Denominator: 250000
    Source_Contribution:
    Digitization of geologic boundaries and formation ID attribution.

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

    Date: 1986 (process 1 of 6)
    Delineation of the official NC State Geologic formations.

    Person who carried out this activity:

    North Carolina Geological Survey
    c/o Jeff Reid
    Chief Geologist
    512 North Salisbury St.
    Raleigh, NC 27604-1148
    U.S.A

    (919) 733-2423 (voice)
    (919) 733-0900 (FAX)
    Jeff.Reid@ncmail.net

    Hours_of_Service: 9 a.m. - 5 p.m.
    Contact_Instructions: Preferred contact is by telephone or email
    Date: 1993 (process 2 of 6)
    Digital conversion of the geologic formation delineations through the use of Calcomp digitizing tables into ESRI's ARC/INFO software.

    Person who carried out this activity:

    North Carolina Center for Geographic Information and Analysis
    c/o David Giordano
    Database Administration
    301 N. Wilmington Street, Suite 700
    Raleigh, North Carolina 27601-2825
    U.S.A.

    (919) 733-2090 (voice)
    (919)715-0725 (FAX)
    dataq@ncmail.net

    Hours_of_Service: 8am to 5pm
    Contact_Instructions: Phone and electronic mail preferred
    Date: 1998 (process 3 of 6)
    Digitization correction and attributes included

    Person who carried out this activity:

    North Carolina Geological Survey
    c/o Jeff Reid
    Chief Geologist
    512 North Salisbury St.
    Raleigh, NC 27604-1148
    U.S.A

    (919) 733-2423 (voice)
    (919) 733-0900 (FAX)
    Jeff.Reid@ncmail.net

    Hours_of_Service: 9 a.m. - 5 p.m.
    Contact_Instructions: Preferred contact is by telephone or email
    Date: 28-Sep-2007 (process 4 of 6)
    Conversion from Arc/Info Coverage to Personal Geodatabase Feature Class.

    Person who carried out this activity:

    John Nickerson
    North Carolina Geological Survey
    Geologist
    1612 Mail Service Center
    Raleigh, NC 27699-1612
    USA

    919-733-2423 (voice)
    john.nickerson@ncmail.net

    Hours_of_Service: 8 a.m. - 5 p.m.
    Data sources used in this process:
    • none

    Date: 02-Jul-2009 (process 5 of 6)
    Tables were joined to this feature class to provide a complete dataset. Feature Class was exported to shapefile format for maximum compatibility with users.

    Person who carried out this activity:

    John Nickerson
    NC Geological Survey
    Geologist
    1612 Mail Service Center
    Raleigh, NC 27699-1612
    USA

    919-733-2423 (voice)
    john.nickerson@ncdenr.gov

    Hours_of_Service: 8-5, m-f
    Data sources used in this process:
    • none

    Date: 2009 (process 6 of 6)
    ArcGIS layer file was created for this shapefile by matching as closely as possible the colors and patterns present on the published 1985 Geologic Map of North Carolina. Layer file created for ArcGIS geol250_polygons_92.lyr = ArcGIS 9.2 and above.

    Person who carried out this activity:

    Michael Medina
    NC Geological Survey
    Engineering Technician
    1612 Mail Service Center
    Raleigh, NC 27699-1612
    USA

    919-733-2423 (voice)
    michael.medina@ncdenr.gov

    Hours_of_Service: 8-5, M-F, EST
  3. What similar or related data should the user be aware of?

    NC DENR-Division of Land Resour, NC Geological Survey, 1999, Geology - North Carolina (1:250,000) Polygons: NC DENR-Division of Land Resources, NC Geological Survey, Raleigh, North Carolina.

    Online Links:

    • none

    Other_Citation_Details: Digitized by NC CGIA
    NC DENR-Division of Land Resour, NC Geological Survey, 1999, Geology - North Carolina (1:250,000) Structures: NC DENR-Division of Land Resources, NC Geological Survey, Raleigh, North Carolina.

    Online Links:

    Other_Citation_Details: Digitized by NCCGIA

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

  1. How well have the observations been checked?

    NCCGIA digitized the geology features from mylar stable bases identifying boundary and name attributes of geologic features. A review by check plot overlay was used to determine label discrepancies and found discrepancies were corrected. NCGS entered attribute information into a database and checked the printed database against the paper 1985 Geologic Map.

  2. How accurate are the geographic locations?

    No official accuracy assessment has be performed on this data set. The digital files were checked to within a linewidth of the original base maps. The base maps were delineated with geologic extents identified by the U.S. Geological Survey and the NC Geologic Survey.

  3. How accurate are the heights or depths?

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

    These data represent the official geologic map of North Carolina. The information consists of three coverages and five text files of attributes, which depict the state's geologic formations, its structures, and its dikes.

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

    Using ESRI's ARC/INFO GIS software, the dataset was built for arc and polygon topology using the "build" command. The data set was then cleaned with a fuzzy tolerance of 1 meter. Topology has not been edited since the last build or clean.

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 products derived form this data set should cite the following: The source of the Geologic (1:250,000) data is the North Carolina Corporate Geographic Database. Earlier versions of this data set may exist. The user must be sure to use the appropriate data set for the time period of interest. While efforts have been made to ensure that these data are accurate and reliable within the state of the art, CGIA cannot assume liability for any damages or misrepresentation caused by any inaccuracies in the data or as a result of changes to the data caused by system transfers.

  1. Who distributes the data set? (Distributor 1 of 1)

    North Carolina Geological Survey
    c/o John Nickerson
    Geologist
    512 North Salisbury St.
    Raleigh, NC 27604-1148
    U.S.A

    (919) 733-2423 (voice)
    (919) 733-0900 (FAX)
    john.nickerson@ncmail.net

    Hours_of_Service: 8 a.m. - 5 p.m.
    Contact_Instructions: Preferred contact is by telephone or email
  2. What's the catalog number I need to order this data set?

    Geology - North Carolina (1:250,000)

  3. What legal disclaimers am I supposed to read?

    The North Carolina Geological Survey (NCGS) is committed to offering its users accurate, useful, and current information. Although every effort has been made to ensure the accuracy of information it provides, the NCGS shall not be held liable for improper or incorrect use of the data described and/or contained herein. The information contained in these data is dynamic and may change over time. The client must be aware of data conditions and bear responsibility for the appropriate use of the information with respect to possible errors, original map scale, collection methodology, currency of data, and other conditions specific to certain data.
    The NCGS gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are acquired directly from an NCGS source and not indirectly through other sources which may have modified the data in some way.
    Although these data have been processed successfully on computer systems at the NCGS, no warranty expressed or implied is made regarding the utility of the data on other systems for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. The use of trade names or commercial products does not constitute their endorsement by the NCGS.
    NCCGIA is charged with the development and maintenance of NC OneMap and, in cooperation with other mapping organizations, is committed to offering its users accurate, useful, and current information. Although every effort has been made to ensure the accuracy of information, errors and conditions originating from physical sources used to develop this dataset may be reflected in the data supplied. The user must be aware of possible conditions and bear responsibility for the appropriate use of the information with respect to possible errors, original map scale, collection methodology, currency of data, and other conditions specific to certain data. NCCGIA does not support secondary distribution of this dataset without its current, compliant metadata record. The use of trade names or commercial products does not constitute their endorsement by NCCGIA or North Carolina State Government.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Data can be customized on a cost-recovery basis. Contact dataq@ncmail.net or 919-733-2090 for more information.

  6. What hardware or software do I need in order to use the data set?

    All formats available from www.nconemap.com are in ESRI shapefile. Other formats are available on a cost-recovery basis - contact dataq@ncmail.net or 919.733.2090 for more information. Format compatibility is the user's responsibility.

Who wrote the metadata?

Dates:
Last modified: 17-Jul-2009
Metadata author:
North Carolina Geological Survey
c/o John Nickerson
Geologist
512 North Salisbury St.
Raleigh, NC 27604-1148
U.S.A

(919) 733-2423 (voice)
(919) 733-0900 (FAX)
john.nickerson@ncmail.net

Hours_of_Service: 9 a.m. - 5 p.m.
Contact_Instructions: Preferred contact is by telephone or email
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.5 on Wed Nov 25 16:23:09 2009