Dating Methodology and its Associated Assumptions

The KBS Tuff dating fiasco (1976 "Nature" magazine) used Isochron methods, the very methods that are claimed to ensure errors cannot occurr because of anomalous loss or gain of argon.

Dating of this tuff by the K-Ar and 40Ar-39Ar methods had given a wide range of numerical ages from about 1.6 to 2.6 Ma, leading to much debate, particularly as the older age would have meant that ER 1470 was the oldest hominid known at that time. The co-leaders of the Koobi Fora Research Expedition, Richard Leakey and Glynn Isaac, invited me to participate in further isotopic dating of the tuffs, a number of which were known to occur in the sedimentary sequence. In principle, isotopic dating of alkali feldspar crystals found within pumice clasts in a tuff would yield an age for the igneous eruption. As deposition of a tuff within a sedimentary basin generally would have occurred within a very short interval after the eruption, days to perhaps tens of years, extending to hundreds of years at most, the age obtained on a tuff also provides a close estimate of the age of deposition. Thus, in 1978 I was able to undertake field work at Koobi Fora, collecting pumice clasts and tuffs from a number of horizons throughout the sequence, under the guidance of the geologist of the expedition at that time, Ian Findlater. Subsequently, our initial K-Ar and 40Ar-39Ar dating results on the KBS Tuff were published in Nature in 1980 and 1981, showing that it had a quite reproducible age of 1.88 0.02 Ma. These results were seen as resolving the controversy on the numerical age of the KBS Tuff and thus of ER 1470 recovered from sediments just below the tuff (e.g. see Hay, R. L., Nature 284: 401, 1980).

Dating of this tuff by the K-Ar and 40Ar-39Ar methods had given a wide range of numerical ages from about 1.6 to 2.6 Ma, leading to much debate, particularly as the older age would have meant that ER 1470 was the oldest hominid known at that time. The co-leaders of the Koobi Fora Research Expedition, Richard Leakey and Glynn Isaac, invited me to participate in further isotopic dating of the tuffs, a number of which were known to occur in the sedimentary sequence. In principle, isotopic dating of alkali feldspar crystals found within pumice clasts in a tuff would yield an age for the igneous eruption. As deposition of a tuff within a sedimentary basin generally would have occurred within a very short interval after the eruption, days to perhaps tens of years, extending to hundreds of years at most, the age obtained on a tuff also provides a close estimate of the age of deposition. Thus, in 1978 I was able to undertake field work at Koobi Fora, collecting pumice clasts and tuffs from a number of horizons throughout the sequence, under the guidance of the geologist of the expedition at that time, Ian Findlater. Subsequently, our initial K-Ar and 40Ar-39Ar dating results on the KBS Tuff were published in Nature in 1980 and 1981, showing that it had a quite reproducible age of 1.88 0.02 Ma. These results were seen as resolving the controversy on the numerical age of the KBS Tuff and thus of ER 1470 recovered from sediments just below the tuff (e.g. see Hay, R. L., Nature 284: 401, 1980).

Dating of this tuff by the K-Ar and 40Ar-39Ar methods had given a wide range of numerical ages from about 1.6 to 2.6 Ma, leading to much debate, particularly as the older age would have meant that ER 1470 was the oldest hominid known at that time. The co-leaders of the Koobi Fora Research Expedition, Richard Leakey and Glynn Isaac, invited me to participate in further isotopic dating of the tuffs, a number of which were known to occur in the sedimentary sequence. In principle, isotopic dating of alkali feldspar crystals found within pumice clasts in a tuff would yield an age for the igneous eruption. As deposition of a tuff within a sedimentary basin generally would have occurred within a very short interval after the eruption, days to perhaps tens of years, extending to hundreds of years at most, the age obtained on a tuff also provides a close estimate of the age of deposition. Thus, in 1978 I was able to undertake field work at Koobi Fora, collecting pumice clasts and tuffs from a number of horizons throughout the sequence, under the guidance of the geologist of the expedition at that time, Ian Findlater. Subsequently, our initial K-Ar and 40Ar-39Ar dating results on the KBS Tuff were published in Nature in 1980 and 1981, showing that it had a quite reproducible age of 1.88 0.02 Ma. These results were seen as resolving the controversy on the numerical age of the KBS Tuff and thus of ER 1470 recovered from sediments just below the tuff (e.g. see Hay, R. L., Nature 284: 401, 1980).

In fact, McDougall also revealed the "scatter" that Fitch chastised Berkeley for was even greater in his reported results.McDougall (on Fitch scatter): 0.52 to 2.64 million years for one set of samples and ages of 8.43 to 17.5 million years on another set before settling on their 2.6 million date.

This date only split the difference of the discordant dates produced by our two top notch teams leaving the descrepancy only half as much for both sides.

Thus, in 1978 I was able to undertake field work at Koobi Fora, collecting pumice clasts and tuffs from a number of horizons throughout the sequence, under the guidance of the geologist of the expedition at that time, Ian Findlater.

Thus, in 1978 I was able to undertake field work at Koobi Fora, collecting pumice clasts and tuffs from a number of horizons throughout the sequence, under the guidance of the geologist of the expedition at that time, Ian Findlater.

Your above comment is an unsupported opinion uttered to trick an Admin into intervening in your behalf.

Jar:With all due respect I am not engaged here to "learn" per se.

For the most part you have only argued by website.

One of the nice things about science is the key issue of reproduciblity. Issues like age or other controversial questions are subjected to peer review and testing by other researchers. In this case multiple samples from multiple sites were used to cross check with the result that the tufs were dated with a high degree of confidence.

Again, you make these totally unsupported assertions. According to what Dr. McDougall said, "Dating of this tuff by the K-Ar and 40Ar-39Ar methods had given a wide range of numerical ages from about 1.6 to 2.6 Ma".

There was no spliting of the dates. Instead, all new samples were gathered at the site under the supervision of the geologist. Those new samples were analyzed.

WILLOWTREE writes:Jar, I thought you were a Bible believing Protestant ?, if I am right, then the Bible is perceived better. This shoud be a win/win for you - no ?

What about the discard dates in the KBS Tuff dating fiasco ?Those discard dates ranged from one half million to 17.5 million years. (already posted - do you want me to retrieve them ?)This is the precise context of the accusation.

That too is false. You have been shown that is a false assertion by direct link to the interview with Ian McDougall, the person who did the dating.

The Red Hand of Zara proves that no amount of evidence and no matter how clear - you will deny the obvious.

On this basis I must conclude that the same dishonesty must extend into your arguments about evolution = proven bias against Bible regardless of evidence.