New Publication (September 2020): Cogliatti et al. Journal of the Geological Society, London

Simone Cogliati, Sarah Sherlock, Alison Halton, Alena Ebinghaus, Simon, Kelley, David Jolley & Tiffany Barry. "Expanding the toolbox for dating basaltic lava sequences: 40Ar–39Ar dating of silicic volcanic glass from interbeds." Journal of the Geological Society, London, 178 (1).

This new publication by Cogliatti et al is the 1st paper from Simones PhD research, focusing on Ar/Ar and noble gas behaviour in volcanic glass. In this paper we have used Ar/Ar dating of silicic glasses from interbeds in the Columbia River Basalt Province to provide an additional line of evidence for the timing of the eruptions of the lavas. This technique has the potential to allow dating of sequences where the "traditional" argon dating phase for volcanic sequences (normally feldspars, biotite, hornblende) are not available.
The glass shards dated are from silicic tuffs of the Ellensburg Formation (NW, USA) interbedding basaltic lavas and yielded accurate, precise, reproducible plateau and isochron ages that are within error at the 2σ level. The ages of 12.00 ± 0.24, 11.37 ± 0.15, 10.67 ± 0.21 and 10.70 ± 0.18 Ma produced are consistent with the stratigraphy of four of the dated layers; the age of 10.77 ± 0.18 Ma for a fifth layer is at odds with the stratigraphy, with this discrepancy thought to arise due to the effect of glass alteration that induced K- and Ar-loss but with no evidence of excess 40Ar or 39Ar recoil from the glass.