EarthRef.org Digital Archive (ERDA)
Development and Maintenance by the EarthRef.org Database Team

Detailed File Information
Typical Argon Isotope Mass Spectrum for K/Ar Age Dating
File Name m00053.img.821.mass.spectrum.k.ar.jpg
Data Type diagram
Computer Program Adobe Illustrator CS2
File Size 228.00 KB - 2 files [ jpg,pdf ]
Expert Level College and Introduction to Science
Contributor ERESE Database Team
Source Dickin 1995
Resource Matrix 40Ar/39Ar Geochronology
Description
In this schematic spectrum for a typical spiked K/Ar measurement all fractions are shown for the peaks measured at mass 36, 38 and 40. An aliquot of Argon enriched in 38Ar is added to the gas extracted from a geological sample to carry out an isotope dilution experiment. After correcting for the atmospheric component in the gas sample, this added spike allows us to calculate how much radiogenic 40Ar resides in the sample. Together with an independent determination of the abundance of Potassium in the same geological material, a K/Ar age can be calculated. Note that the fractions are not to scale, because these vary for each different geological sample being analyzed and for each different Argon spike applied. Modified after Dalrymple & Lanphere 1969.
Click to return to previous page