The validity of either hypothesis #2 or #3 would provide additional evidence that Austin's application of the K-Ar method is flawed and that he has failed to prove that the K-Ar method is universally invalid.A British team reported finding markings in a layer of volcanic ash in a Mexican quarry that they interpreted as human footprints. Bennett, Silvia Gonzalez, David Huddart (2010) Techniques for verifying human footprints: reappraisal of pre-Clovis footprints in Central Mexico Quaternary Science Reviews, Volume 29, Issues 19-20, September 2010, Pages 2571-2578."You have to remember this is a public area," Renne said in a telephone interview. In his 1988 paper, Austin noted that this sort of "false isochron" is well known, and explained in the mainstream literature. 145-147), a popular textbook/handbook on isotope dating methods.
In 1969 over 175 bone fragments were found on the edge of dry Lake Mungo in New South Wales.
They were the remains of a woman, and were carbon dated to between 24,500 and 26,500 years old.
The five examples listed here are all cited in In each case the K-Ar method is applied to a historical lava flow of known age less than 2200 years, and the radiometric age is calculated to be between a few hundred thousand and a few million years.
The 79 CE Mt Vesuvius flow, the dating of which is described above, also contained excess 40Ar.
If the radioactive decay rates were miraculously increased during the flood, then the development of orbital parameters must have been accelerated in just the same way.
This section lists examples of radiometric dates which are inconsistent with known dates, inconsistent with each other, seriously inconsistent with the uniformitarian timescale, or inconsistent with other evidence.
More successful was the Optically Stimulated Luminescence (OSL) method to date quartz crystals found in baked lake sediments incorporated into the ash (as xenoliths) and secured an age of around 40,000 years. Bennett and Alberto González-Huesca (2006) Human footprints in Central Mexico older than 40,000 years. Whether this has actually occured can usually be determined by plotting the data is a different way. Leeman's paper contains quite a bit more data than Austin used, with sufficient scatter to suggest that the resulting isochron probably is either an "inherited" reflection of the mantle source age or has no significance at all.
The sample was taken from the working quarry, 200m south from where the footprints were found. However, Austin narrowed down the data set to flows which fell into a particular stratigraphic range -- "stages III and IV of Hamblin's later classification," said Austin (1988) -- and those selected data points fell quite close to a single line.
Thus, it is misleading for Austin to pretend that his resulting isochron plot should be expected to represent the age of the flows themselves.
The isotopic and chemical data are compatible with the model proposed by Best and Brimhall (1974) in which the Grand Canyon basalt flows are derived by variable degrees of partial melting of mantle material over a range in depth and modified by polybaric crystal fractionation during ascent to the surface.
Thus the large majority of historic lava flows that have been studied either give correct ages, as expected, or have quantities of excess radiogenic 40Ar that would be insignificant in all but the youngest rocks.