Potassium argon dating is only done with
Y."; also see discussions by advanced equipment, 'memory effects' can be a problem with very young samples (Dalrymple, 1969, p. That is, very tiny amounts of argon contaminants from previous analyses may remain within the equipment, which precludes accurate dates for very young samples.
'(e.g., Harland et al., 1990; Hilgen et al., 1997, p. 121-122; Baadsgaard et al., 1988; Baadsgaard et al., 1993; Queen et al., 1996; Montanari et al., 1985; and Hirschmann et al., 1997; also see Austin clearly ignores the possibility of contamination in the mass spectrometer (hypothesis #2) and the possibility that the phenocrysts in his samples may be much older than the 1986 AD eruption (hypothesis #3).
On the basis of the glass and mineral textures and elementary melt chemistry, we know that the zoned plagioclases and other relatively large and well-developed minerals in Austin's dacite must have taken more time to grow than the surrounding glass matrix.
By using high-temperature ovens in undergraduate university laboratories or even crystal-growing kits and kitchen chemicals, a normally intelligent person can verify that coarse crystals take more time to grow than finer-grained materials. Farrar, 1996, '40Ar/39Ar Phlogopite and U-Pb Perovskite Dating of Lamprophyre Dykes from the Eastern Lake Superior Region: Evidence for a 1.14 Ga Magmatic Precursor to Midcontinent Rift Volcanism', Can.
Considering the statements at the Geochron website and the lowest age limitations of the K-Ar method, why did Austin submit a recently erupted dacite to this laboratory and expect a reliable answer???
uninformed claim that ' Dr Austin carefully designed the research to counter all possible objections', Austin clearly demonstrated his inexperience in geochronology when he wasted a lot of money using the K-Ar method on the wrong type of samples.
9), the K-Ar method cannot be used to date samples that are much younger than 6,000 years old (Dalrymple, 1991, p.