Calibration of the interlaboratory 40Ar39Ar dating standard, MMhb-1

Scott D. Samson, E. Calvin Alexander

Research output: Contribution to journalArticlepeer-review

707 Scopus citations


KAr data has been compiled from over 18 laboratories on the 40Ar39Ar dating standard, MMhb-1. The new recommended age for the monitor is 520.4 ± 1.7 Ma. The interlaboratory precision for K is 1.06% and for Ar is 1.89%. 40Ar-39Ar analyses of MMhb-1 have shown that the 40Ar{black star} 40K ratio is uniform at better than the 0.1% level, thus variations in the conventional determinations are a result of systematic variations and interlaboratory biases. We recommend a set of 40Ar39Ar standards be prepared and adopted by the KAr community to reduce uncertainty in intersample age comparison. Further, an organization like the U.S. National Bureau of Standards should be encouraged to "unconventionally" calibrate these monitors if the precision of which the 40Ar39Ar technique is capable is to be approached.

Original languageEnglish (US)
Pages (from-to)27-34
Number of pages8
JournalChemical Geology: Isotope Geoscience Section
Issue number1-2
StatePublished - Nov 25 1987
Externally publishedYes

ASJC Scopus subject areas

  • General Environmental Science
  • General Earth and Planetary Sciences


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