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Mineral Resources On-Line Spatial Data

K/Ar ages from the National Geochronological Data Base

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Metadata:

Identification_Information
Data_Quality_Information
Spatial_Data_Organization_Information
Spatial_Reference_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: U.S. Geological Survey

Publication_Date: 2002

Title: K/Ar ages from the National Geochronological Data Base

Edition: version 1.0

Geospatial_Data_Presentation_Form: tabular digital data

Larger_Work_Citation:

Citation_Information:

Originator: Zartman, Robert. E.

Originator: Bush, Charles. A.

Originator: Abston Carl

Title: National geochronological and natural radioelement data bases

Publication_Date: 1995

Series_Information:

Series_Name: U.S. Geological Survey Digital Data Series
Issue_Identification: DDS-14

Online_Linkage: <http://edc.usgs.gov/glis/hyper/guide/ngdb>

Description:

Abstract:: This data set, dds14kar, is a subset of the National Geochronological Data Base (NGDB), as published in 1995. It shows the distribution of published K/Ar and Ar/Ar age determinations in the United States. Sample location, rock description, analytical data, age, interpretation, and literature citation is given for each record.
Purpose:: This GIS representation of the data set facilitates the presentation and analysis of earth-science data.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1995

Currentness_Reference: publication date

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: 177.5
East_Bounding_Coordinate: -67.1
North_Bounding_Coordinate: 71.0
South_Bounding_Coordinate: 25.3

Keywords:

Theme:

Theme_Keyword_Thesaurus: None
Theme_Keyword: K/Ar geochronology
Theme_Keyword: Ar/Ar geochronology
Theme_Keyword: radiometric age
Theme_Keyword: geochronology

Place:

Place_Keyword_Thesaurus: None
Place_Keyword: US
Place_Keyword: United States of America

Access_Constraints: None

Use_Constraints:

The U.S. Geological Survey makes no warranties related to the accuracy of the data and users are required to determine the usability for any particular purpose.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey
Contact_Person: Nora Shew

Contact_Address:

Address_Type: mailing and physical address
Address: 4200 University Drive
City: Anchorage
State_or_Province: AK
Postal_Code: 99508-4667
Country: U.S.A.

Contact_Voice_Telephone: 907-561-1181

Contact_Electronic_Mail_Address: nshew@usgs.gov

Data_Set_Credit:

The National Geochronological data base is maintained by the U.S. Geological Survey. It was published by Robert E. Zartman, Charles A. Bush, and Carl Abston in 1995. The K/Ar and Ar/Ar portion of the data base was prepared for by Nora Shew and Tom Kress.

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:: The radiometric ages are given in m.y., millions of years. The analytical error, also given in m.y., is listed for most ages. The numerical precision was not maintained during the data conversion and the user should be aware that more precision may be indicated than is real. Users should use this data set to learn about existing data, then research the original references to gain more information about the sample, analysis, and interpretation.

Logical_Consistency_Report:

This is a point data set, where each point represents a published analytical age determination. If an age is published in multiple references, it is represented as a single point and only a single reference is cited.

Completeness_Report:

This data set contains a subset of the National Geochronological data base, NGDB. Data for samples dated by a potassium-argon dating method and include location information are given here. The data set does not include the following dating methods: fission track, lead alpha, rubidium-strontium, samarium-neodymium, or uranium-thorium-lead. In addition, many fields associated with the K/Ar and Ar/Ar records were not included. Some of the missing fields are: analysis number, lab number, suite number, mineral code, county, quadrangle, scale, source, geo unit, petrographic code, lab code, and lexicon age.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:: The precision of the latitude and longitude values was not maintained during the data conversion and the user should be aware that more precision may be indicated than is real. The text field 'Precision' describes the positional accuracy of each point.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Zartman, Robert E.

Originator: Bush, Charles A.

Originator: Abston, Carl

Publication_Date: 1995

Title: National Geochronological Data Base

Geospatial_Data_Presentation_Form: tabular digital data

Series_Information:

Series_Name: U.S. Geological Survey Digital Data Series
Issue_Identification: DDS-14A

Type_of_Source_Media: CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1995

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: DDS-14A

Source_Contribution: The entire data set was obtained from DDS-14A.

Process_Step:

Process_Description:: The National Geochronologic data base (NGDB) is stored in a relational data base program. DDS-14A published the data as a relational data base and separate ASCII format. The comma seperated value files were imported into database software, Access, where the table relationships were re-built. It was necessary to edit some records in order for the data base to be re-built. The actual data values were not changed. Once the Access data base was completed, select fields were used to build a DBF file. Using ArcView a shapefile was produced called dds14_k_ar_age.shp
Process_Date: 2001

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Point

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: .002
Longitude_Resolution: .002
Geographic_Coordinate_Units: Decimal degrees

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: points
Entity_Type_Definition: Rock or mineral sample dated by K/Ar geochronology

Attribute:

Attribute_Label: Recno (Record Number)

Attribute_Definition:

Unique NGDB identifier for sample. Multiple analyses on a single sample have the same Record Number.

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 3
Range_Domain_Maximum: 18332

Attribute:

Attribute_Label: Rockname (Rock)

Attribute_Definition: Rock type from which the dating sample is from

Attribute_Domain_Values:

Unrepresentable_Domain: descriptive text of mixed case

Attribute:

Attribute_Label: Mineral

Attribute_Definition: Mineral or phase dated

Attribute_Domain_Values:

Unrepresentable_Domain: descriptive text of mixed case

Attribute:

Attribute_Label: Age

Attribute_Definition: Age of sample in millions of years (m.y.)

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.09
Range_Domain_Maximum: 6883
Attribute_Units_of_Measure: m.y. (million years)

Attribute:

Attribute_Label: Error

Attribute_Definition: Analytical error of calculated age

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 940
Attribute_Units_of_Measure: m.y. (million years)

Attribute:

Attribute_Label: Analysisty

Attribute_Definition: Method of K/Ar dating

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 37Ar-41Ar total fusion
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 39Ar-40Ar incremental (plateau)
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 39Ar-40Ar total fusion
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 40Ar-40K isochron
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 40Ar/36Ar-40K/36Ar isochron
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Conventional K-Ar
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Conventional Rb-Sr (assumed initial 87Sr/86Sr)
Enumerated_Domain_Value_Definition:

Attribute:

Attribute_Label: Agecomment

Attribute_Definition:

Informative text about the estimated age or the material analyzed

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age meaning uncertain (analysis questionable)
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age meaning uncertain (geologic factors)
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age not evaluated
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age of intrusion
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age of later metamorphism
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age of metamorphic crystallization
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age of sedimentation
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age of uplift and cooling
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age of volcanism
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: age reset by thermal event
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: anomalous initial isotopic composition, age questionable
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: initial age disturbed by later metamorphism
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: initial age disturbed by weathering
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: maximum age of intrusion
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: maximum age of metamorphic crystallization
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: maximum age of volcanism
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: may denote delayed cooling
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: minimum age of intrusion
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: minimum age of metamorphic crystallization
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: minimum age of mineralization
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: minimum age of volcanism
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: sample contains excess radiogenic argon, age is too old
Enumerated_Domain_Value_Definition:

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: sample contains inherited material, age is too old
Enumerated_Domain_Value_Definition:

Attribute:

Attribute_Label: K2Opct

Attribute_Definition: percent K20

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 64
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: Ar40mol

Attribute_Definition: radiogenic 40Ar expressed as mol/gm scaled by 1.0E-10

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.000000
Range_Domain_Maximum: 2453.000000
Attribute_Units_of_Measure: mol/gm

Attribute:

Attribute_Label: Arradpct (Arrad%)

Attribute_Definition: Percent radiogenic Ar

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 100
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: Deccon (Decay constant)

Attribute_Definition: Potassium decay contants used in age calculation

Attribute_Domain_Values:

Unrepresentable_Domain: text

Attribute:

Attribute_Label: Latitude

Attribute_Definition: latitude in decimal degrees

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 26.67
Range_Domain_Maximum: 71.0
Attribute_Units_of_Measure: degree

Attribute:

Attribute_Label: Latdir

Attribute_Definition: Direction of latitude

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: N
Enumerated_Domain_Value_Definition: North

Attribute:

Attribute_Label: Longitude

Attribute_Definition: longitude in decimal degrees

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -67.1
Range_Domain_Maximum: 177.5
Attribute_Units_of_Measure: degree

Attribute:

Attribute_Label: Longdir

Attribute_Definition: Direction of Longitude

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: E
Enumerated_Domain_Value_Definition: East

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: W
Enumerated_Domain_Value_Definition: West

Attribute:

Attribute_Label: St (State)

Attribute_Definition: Two letter abbreviation for State sample was collected from

Attribute_Domain_Values:

Codeset_Domain:

Codeset_Name: Two-letter abbreviations for US states
Codeset_Source: USPS

Attribute:

Attribute_Label: Precision

Attribute_Definition: Description of location precision

Attribute_Domain_Values:

Unrepresentable_Domain: descriptive text

Attribute:

Attribute_Label: Refcode
Attribute_Definition:: NGDB coded value linking radiometric date with published reference

Attribute:

Attribute_Label: Reference

Attribute_Definition: Reference which is the source of the analytical information

Attribute_Domain_Values:

Unrepresentable_Domain: bibliographic citation

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey
Contact_Person: Tom Kress

Contact_Address:

Address_Type: mailing address
Address: 12201 Sunrise Valley Drive MS954
City: Reston
State_or_Province: VA
Postal_Code: 20192
Country: USA

Contact_Voice_Telephone: 703-648-6328

Contact_Electronic_Mail_Address: thkress@usgs.gov

Resource_Description: dds14k_ar_age.shp

Distribution_Liability:

The U.S. Geological Survey (USGS) provides this point data "as is." The USGS makes no guarantee or warranty concerning the accuracy of information contained in the dataset. Further, the USGS makes no warranties, either expressed or implied, as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although this data has been processed successfully on computers at the USGS, no warranty, express or implied, is made by the USGS regarding the use of this data on any other system, nor does the fact of distribuiton constitute or imply any such warranty.

Standard_Order_Process: