Journal article

Astronomical calibration of Ar-40/Ar-39 reference minerals using high-precision, multi-collector (ARGUSVI) mass spectrometry

D Phillips, EL Matchan, M Honda, KF Kuiper

Geochimica et Cosmochimica Acta | Elsevier | Published : 2017

Abstract

The new generation of multi-collector mass spectrometers (e.g. ARGUSVI) permit ultra-high precision (1%) in 40K decay constants and the ages of natural reference minerals that form the basis of the technique. For example, reported ages for widely used 40Ar/39Ar reference materials, such as the ca. 28 Ma Fish Canyon Tuff sanidine (FCTs) and the ca. 1.2 Ma Alder Creek Rhyolite sanidine (ACRs), vary by >1%. Recent attempts to independently calibrate these reference minerals have focused on K–Ar analyses of the same minerals and inter-comparisons with astronomically tuned tephras in sedimentary sequences and U–Pb zircon ages from volcanic rocks. Most of these studies used older generation (effec..

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Grants

Awarded by Australian Research Council Discovery grant


Funding Acknowledgements

This study is supported by Australian Research Council Discovery grant DP130100517 to D. Phillips. S. Szczepanski is thanked for technical assistance in the Melbourne <SUP>40</SUP>Ar/<SUP>39</SUP> Ar laboratory. We acknowledge John Hellstrom for discussions on the statistical protocols. The manuscript has benefitted from thoughtful reviews by Brad Singer, Leah Morgan, one anonymous reviewer and the associate editor, Chris Hall.