The conventional K-Ar dating method was applied to the 1986 dacite flow
from the new lava dome at Mount St. Helens, Washington. The whole-rock
age was 0.35 +/- 0.05 million years (Mya). Ages for component minerals
varied from 0.34 +/- 0.06 Mya to 2.8 +/- 0.6 Mya. These ages show that
the K-Ar method is invalid.
Austin sent his samples to a laboratory that clearly states that their
equipment cannot accurately measure samples less than two million years
old. All of the measured ages but one fall well under the stated limit
of accuracy, so the method applied to them is obviously inapplicable.
Since Austin misused the measurement technique, he should expect
inaccurate results, but the fault is his, not the technique's.
Experimental error is a possible explanation for the older date.
Austin's samples were not homogeneous, as he himself admitted. Any
xenocrysts in the samples would make the samples appear older (because
the xenocrysts themselves would be old). A K-Ar analysis of impure
fractions of the sample, as Austin's were, is meaningless.
