Journal article
Ultra-high precision 40Ar/39Ar ages for Fish Canyon Tuff and Alder Creek Rhyolite sanidine: New dating standards required?
D Phillips, EL Matchan
Geochimica Et Cosmochimica Acta | PERGAMON-ELSEVIER SCIENCE LTD | Published : 2013
Abstract
The 40Ar/39Ar dating technique is a high precision (<0.1%) method with wide application to geological samples. However, the method is predicated on the availability of natural mineral standards of known age. Widely used 40Ar/39Ar standards include sanidine from the (ca. 28Ma) Fish Canyon Tuff (FCT) and the (ca. 1.2Ma) Alder Creek Rhyolite (ACR). Despite common usage, the ages of FCT and ACR sanidine have proven contentious, with reported values varying by >2%; well outside the ±0.1% aspiration of EARTHTIME (www.earth-time.org). The current study presents ultra-high precision, multi-collector 40Ar/39Ar results for FCT and ACR sanidine, using a new generation ARGUSVI mass spectrometer. These a..
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Awarded by Australian Research Council
Funding Acknowledgements
This study is supported by Australian Research Council Discovery grants DP0879173 and DP130100517 to D. Phillips. S. Szczepanski is thanked for technical assistance in the Melbourne <SUP>40</SUP>Ar/<SUP>39</SUP>Ar laboratory. The authors acknowledge fruitful exchanges of technical information on the ARGUSVI mass spectrometer with M. Heizler. P. Renne and M. Heizler are thanked for providing coordinates and directions to the FCT and ACR sampling sites. The manuscript has benefitted from insightful comments by I. McDougall on an early draft of the manuscript, as well as formal reviews by K. Kuiper, J. Wijbrans, F. Jourdan and C.M. Hall.