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Mineral Resources On-Line Spatial Data

Interactive maps > Data download > K/Ar ages from the National Geochronological Database

Alphabetical index of database fields

A

Age of sample in millions of years (m.y.) (Analytic result)
Analytical error of calculated age (Analytic result)

D

Description of location precision (Analytic result)
Direction of latitude (Geographic location)
Direction of Longitude (Geographic location)

I

Informative text about the estimated age or the material analyzed (Processing information)

L

latitude in decimal degrees (Geographic location)
longitude in decimal degrees (Geographic location)

M

Method of K/Ar dating (Processing information)
Mineral or phase dated (Sample characteristics)

N

NGDB coded value linking radiometric date with published reference (Processing information)

P

percent K20 (Analytic result)
Percent radiogenic Ar (Analytic result)
Potassium decay contants used in age calculation (Processing information)

R

radiogenic 40Ar expressed as mol/gm scaled by 1.0E-10 (Analytic result)
Reference which is the source of the analytical information (Processing information)
Rock type from which the dating sample is from (Sample characteristics)

T

Two letter abbreviation for State sample was collected from (Geographic location)

U

Unique NGDB identifier for sample. Multiple analyses on a single sample have the same Record Number. (Sample identification)
Unique record identifier (Sample identification)

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