9), the K-Ar method cannot be used to date samples that are much younger than 6,000 years old (Dalrymple, 1991, p.
93)Cambridge, Massachusetts, USA, performed the K-Ar dating for Austin et al. However, when they did, their website clearly stated in a footnote that their equipment could not accurately date rocks that are younger than about 2 million years old ("We cannot analyze samples expected to be younger than 2 M.
However, rather than dealing with this issue and critically evaluating Austin's other procedures (including the unacceptable mineral and glass impurities in his 'fractions'), YECs loudly proclaim that the results are discrepant with the 1986 AD eruption.
Mafic microphenocrysts within these glassy particles were probably dominated by the strongly magnetic Fe-Ti oxide minerals.
The microscopic examination of the 'heavy-magnetic concentrate' also revealed a trace quantity of iron fragments, obviously the magnetic contaminant unavoidably introduced from the milling of the dacite in the iron mortar.
Steve Austin and his associates at the Institute for Creation 'Research' (ICR) collected a dacite sample from Mt. Helens, Washington State, USA, which probably erupted in 1986 AD. then ineffectively separated the sample into several mineral and glass 'fractions', submitted the dacite and its 'fractions' for potassium 40-argon 40 (K-Ar) dating, and subsequently used the bogus results to inappropriately attack the K-Ar method.
Considering that the half-life of potassium-40 (40K) is fairly long (1,250 million years, Mc Dougall and Harrison, 1999, p.
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.
Obviously, if Austin wanted a sample that only represented the material that solidified during the 1986 eruption, he would have had to remove ALL of the plagioclase and other phenocrysts from the glass component.
I've attempted to separate very fined-grained minerals from glass in coal ashes by using magnetic separation and hydrofluoric and other acids. Austin even admits that the dacite is 45% phenocrysts and 'lithic (rock) inclusions.'Although Austin claimed that he took precautions to avoid laboratory contamination and that he and his team removed the obvious xenoliths from the dacite sample, Austin's own words refute Swenson's illusions that the dacite mineral/glass 'fractions' were suitably 'pure' enough for testing the validity of the K-Ar method.
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.
For older samples, which contain more 40Ar, the contamination is diluted and has insignificant effects. De Paolo, 1998, 'Intercalibration of Standards, Absolute Ages and Uncertainties in 40Ar/39Ar Dating', Chem.
Specifically, Austin admits that most of his fractions are impure when he includes the term 'etc.' after most of the mineral 'fractions' in his table (see above).'Although NOT a complete separation of non-mafic minerals, this concentrate included plagioclase phenocrysts (andesine composition with a density of about 2.7 g/cc) and the major quantity of glass (density assumed to be about 2.4 g/cc).