In replying to your note, I want it clearly understood that my bias is
entirely for an older date for the KBS tuff. I would love it to be older
because if it truly is 2.6 million years old, then we have a member of our
genus, Homo, from nearly 3 million years ago. If you have read anything on
my web page you will know that this is exactly what I would want to have.
Unfortunately, I must deal with the data not with what I want it to be. So
contrary to my own personal desires in the matter, I have to accept the
younger age for the KBS Tuff. I am going to explain from a different tack
what happened there.
At 10:39 AM 11/17/97 -0600, Karen G. Jensen wrote:
>Now what actually happened with this? Watch the sequence of events:
>
>Early attempts to date the KBS tuff (1969) gave an age of 212-230 million
>years which was immediately rejected as an extraneous argon age
>discrepancy, because of the presence of Australopithicine and other
>mammalian fossils beneath the tuff (Fitch & Miller 1970, Nature 226:226-8).
>The dating was complicated because the tuff is a water-transported mixture.
>But they did find an acceptable date, which was then confirmed by several
>"independent methods":
>
The best tuffs to date are air fall tuffs which are NOT reworked with other
material. If they are water borne then they will be mixed up with older
material.
I might also point out that this extraneous age was rejected also because
there are tuffs above and below the KBS which also can be dated and that 212
million year old date was anomalous for other dates from the same area.
Remember what I told Don Page tonight. When I was a senior in college I
measured the speed of light as being slightly slower than the currently
accepted value. Are we to conclude that on that day, the speed of light was
really slower? Of course not. Every experiment has error and some errors
are doozies. But I might note that contrary to what young-earth
creationists often say, that bad radioactive dates are not published, you
know of this bad date precisely because it was published!
>In the early 1970's the KBS tuff was "securely dated" at 2.6 million years
>based on:
>
> - Vertebrate faunas -- Elephant, Suid (pig), Australopithicus, and
>tools
> (Maglio, 1972; Nature 239:379-85, Leaky, 1967-69, etc.)
>
> - Potassium-Argon dating -- selected crystals (K-Ar and Ar40-Ar39)
> (Fitch & Miller '70, Nature 226:226-8 and see 251:214)
>
> - Paleomagnetism -- polarity data, based on 247 samples below KBS tuff
> (Brock & Isaac, 1974, Nature 247:344-48)
>
> - Fission Track Dating -- involving uranium, noting possible reanealing
> (Hurford, 1974, Nature 249:236; '76, 263:738)
I might note that the suid (pigs) were not accepted as being that old.
Johanson and Edey write:
"However, I had visited Koobi Fora in 1971 and knew that its stratigraphy
was extremely complex and difficult to interpret. The deposits were
shallow, and hence easily eroded away or contaminated by other equally
shallow ones. Moreover, the volcanic marker tuffs were not continuous from
site to site. They too were interrupted by erosion and faulting and were
hard to correlate with one another. But what struck me most strongly was
that the animal fossils found just above and below the 2.6-million-year-old
KBS marker tuff did not look like the 2.6-million-year-old fossils from Omo.
Theoretically, animals of that age should have been identical in the two
places, which were only about fifty miles apart. A wide-ranging animal like
an elephant could have--and very well may have --walked from one to the
other. The climate in the two places was the same."
"It was about then that Clark Howell remarked to Basil Cooke, the
pig specialist, 'The Koobi Fora pigs don't look like our pigs from the same
time rage. Their pigs are too young.'" Lucy, p. 145
Now, before you go and say that evolution is ruling the day here, let me
point out that a pig skeleton is just a big sedimentary particle. These
big, biogenic sedimentary particles can be dated not only at Koobi Fora
where the KBS tuff is, but also in the Omo region 50 miles away and at other
farther localities. These dates can then be used to critique other dates
which bound the pigs somewhere else. The pig dates must then fit with the
radioactive dates.
Would you have a problem with correlating two geologic secions if a pink
quartzite was found below a tuff and above a greensand at Omo and then a
pink quartzite was found beneath another tuff and above a greensand 50 miles
away? Why wouldn't you say this is the same bed? This is what you are
doing when you talk about the Morrison formation being widespread.The
Morrison lies above certain beds and below others. Treat the pigs as if they
are a large sedimentary particle, like quartzite or greensand.
When you talk about how widespread the depositional systems were and
implying that this indicates a flood, even in a flood a depositional system
which deposits pig bones should be able to extend merely 50 miles. Even in
your flood views, the pigs should be deposited simultaneously in this
widespread depositional system.
What does this mean? It means that the ages of the same bed didn't match
up. A similar sequence of sedimentary particles (pig bones) and tuffs,
can't both be 2 million years old and 2.6 million years old anymore than you
can be 35 and 45 years old at the same time.
This contradiction required more data. At that time only the Fitch and
Miller date was accepted.
>In the mid 1970's Leaky's team found Skull 1470 below the KBS Tuff
>(Leaky,'73, Nature 242:447, National Geographic June, 1973 pp 819-829) and
>Leaky said, "either we toss out this skull, or we toss out our theories of
>early man". Skull 1470 was "too modern" to be found at that level, if the
>Australopithicenes (found both above and below the KBS tuff) were ancestral
>to modern man.
>
This quotation of Leakey is really ripped out of the context. Johanson and
Edey write:
"On the strength of the 2.6-million-year date for the KBS tuff, Leakey had
asserted that his Homo habilis skull 1470 was 2.9 million years old, which
made it difficult to accept any known australopithecine as an ancestor of
Homo. Leakey therefore, and following his father's belief, had logically
anchored himself in the view that australopithecines were collateral
relatives, and that the Homo ancestor, when discovered, would turn out to be
more Homo-like and less australopithecine-like than any fossil found so
far. To rearrange all that in his mind on the basis of some pig fossils
would be shockingly difficult. 'Either we toss out this skull [1470],' he
wrote in 1973, ' or we toss out our theories of early man. It simply fits no
previous models of human beginnings.' He preferred to toss out the theory
that australopitheciens were ancestors." Lucy p. 171
Then came another strange discovery at Koobi Fora. All over Africa the
earliest Equus fossils ever found were dated at no more than 2 million years
old. Because of his bias that Homo must be old, Leakey sent a man around to
Omo looking for 3 million year old horses teeth. Of this, Johanson and Edey
write:
"'They've got troubles. They have some Equus teeth from below the KBS tuff
at Koobi Fora. By their dating, that would make them nearly three million
years old. That's awkward, because there aren't any Equus teeth in eastern
Africa that are three million years old. The oldest that anybody has found
anywhere are only about two million. Nobody's buying three-million-year-old
Equus teeth. So Harris feels he has to hunt around and find some. I guess
he hoped to find them here." p. 176-177
Once again consider a horse's tooth as merely a sedimentary particle. Just
like more dolomite was deposited in the Ordovician than in the Tertiary, so
different forms of animals are found in various layers.
I have order the Maglio article above, but Johanson and Edey note of Maglio,
that he came to believe that the elephants were not found anywhere else
dated as old as 2.6 million years old either. They say,
"Questions about the KBS tuff had arisen as early as 1972, when Vincent
Maglio, an elephant specialist working at Lake Turkana, came to the
conclusion that the elephant fossils he was studying there were not as old
as the KBS tuff said they were." p. 238
You cited Maglio's article as firmly dating the KBS to 2.6 million years.
That is not what Johanson says. We will see when the article comes in.
Of the dates for the sedimentary pig particles, Johanson and Edey write:
"[Cooke} told the Britis volcanic daters Fitch and Miller that their
estimate of the KBS tuff was wrong, and challenged them to dispute him on
the basis of the fossil correlations he was getting. He cited Mesochoerus
as a two-million-year-old pig everywhere but at Koobi Fora, where it was
claimed to be nearly three million years old." p. 239
John Harris, the guy looking for horses teeth, after hearing this decided to
study everything himself.
"He resolved to make his own biostratigraphic analysis to prove the validity
of the KBS date, and began looking around at the other members of the
Turkana team for someone to help him. His eye lit on Tim White. Tim agreed
to help. The two men made an exhaustive study of the Turkana pigs. When it
was done, Harris was appalled. It indicated that Cooke was right and that
the Lake Turkana dating was wrong." p. 240
Because of Tim White's conclusion, Leakey never again invited him to Koobi
Fora! (p. 242) Fitch and Miller redated the tuff and got a date of 2.4
million years. Curtis then acquired some of the KBS tuff samples he got 1.8
and 1.6 million years. To conclude, Johanson and Edey write:
"I asked Jim Aronson not long ago what he could say about the
700,000 year swing between Fitch-Miller and Curtis.
"'I think it has to do with the purity of the samples,' he said.
'One of the first things Curtis and his group at Berkely documented was that
the KBS sample they had been given was contaminated by a few grains of much
older material. Since we were always operating on the outer fringe of the
capability of the potassium-argon technique, accidental intrusions like that
can loom very large--only a few grains can throw you way off.'
"The Berkeley group, he went on, had spotted some grains of very old
feldspar under the microscope mixed in with the much younger feldspar
crystals that represented the true KBS volcanic event. They had been able
to handpick out the older contaminant before making their test runs. The
results were reassuringly consistent; they were all bunched around 1.8
million years. Even more reassuring was that Curtis had tested two kinds of
material in the sample: feldspar crystals and glasslike pumice, both of
which had usable amounts of potassium. both returned the same age
estimates." p. 243
As long as Curtis had a sedimentological or lithological reason for
selecting the particles he did, then his selection was independent of the
dating.
>Other anthropologists, notably Johanson's team at Berkeley, couldn't accept
>any claim of such modern hominids in strata dated almost 3 million years
>old. They tried to redate the KBS. It was a complex problem because the
>tuff is a slurry of volcanic debris. But they did find and publish a date
>that was suitable to them: 1.8 million years, based on:
>
> - Hominid Fossils -- Skull 1470 and other similar skulls below KBS tuff
>
> - Potassium-Argon (K-Ar) -- on pumice from the KBS tuff
> and Ar-Ar -- on selected feldspar crystals (Ar40-Ar39)
> (Curtis et al,1975, Nature 258:395 (& see 284:229,230 &
>294:123)
And you miss the most important criterion--consistency. ALL the facts have
to fit together.
glenn
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm