Article 136476 of talk.origins: Newsgroups: talk.origins Path: news.helsinki.fi!news.funet.fi!news.csc.fi!news.eunet.fi!EU.net!howland.reston.ans.net!ix.netcom.com!netcom.com!lmd From: lmd@netcom.com (Lee Davidson) Subject: Re: Independent Dating Methods: a Case Study Message-ID: Organization: NETCOM On-line Communication Services (408 261-4700 guest) X-Newsreader: TIN [version 1.2 PL1] References: <42fqk8$q5v@usenet.INS.CWRU.Edu> Date: Wed, 6 Sep 1995 10:22:19 GMT Lines: 1201 Sender: lmd@netcom18.netcom.com C. Allen Roy (hb426@cleveland.Freenet.Edu) wrote: > It has been noised about on T.O. that the dating methods are independant > from each other. However, in the appendix entitled 'The Dating Game' of > Marvin L. Lubenow's book 'Bones Of Contention' (1992), Lubenow documents > a case which shows how that idea may be overly optimistic. > > Lubenow takes a different tack than Lewin's book by the same title > (1987). While dealing with the issues of dating methods Lewin also > discusses the apparent politics involved concerning publishing of > reports. Lewin presents a positive view of the dating methods. > Lubenow's account was written independent from Lewin, and reaches > differing conclusions about the reliability of the dating methods. > > Below is an edited version of "The Dating Game", refer to the full text > for more detail. I'll reply to Lubenow's arguments based on the references listed at bottom. I use the same footnote-number ranges as shown in the list. > > THE DATING GAME (condensed) > > A very popular myth is that the radioactive dating methods are an > independent confirmation of the geologic time scale and the concept of > human evolution. This myth includes the idea that the various dating > methods are independent of one another and hence act as controls. > Perhaps the best way to expose this myth for what it is -- science > fiction -- is to present a case study of the dating of the East African > KBS Tuff strata and the famous fossil KNM-ER 1470, as recorded in the > scientific journals, especially the British journal 'Nature.' > > Richard Leakey, son of famed paleoanthropologists Louis and Mary Leakey, > visitedthe rich fossil deposits east of Lake Rudolf (now Lake Turkana) > in 1967. He was so stunned by what he saw that he immediately organized > an expedition to that area to search for hominid fossils. > > The most important fossil discovered there is KNM-ER 1470. Skull 1470 > is very modern in appearance but was originally believed to be about 2.9 > million years old. This conflict between its modern appearance and its > ancient age presented a serious challenge to all currently held theories > of human evolution. It precipitated a conflict over the dating of the > fossil which lasted ten years. I already commented, in an earlier post, about how misleading this is. "Modern" suggests "just like homo sapiens in historical times," when, in reality, what was modern about 1470 was its "large" almost 800 cc crainal capacity, among other things. And the "serious challenge" was not to evolutionary theory in general, but to just one particular chronology of human origins. "Ancient" in this context also should not be taken to mean "millions of years old as opposed to thousands of years old," but rather "2.9 million years old instead of 2.1 (say)." > In seeking to unravel the geology of the area, Kay Behrensmeyer > discovered a layer of volcanic ash or tuff that turned out to be crucial > in the dating of the fossils and the artifacts found in association with > it. The spot where she first located this tuff bacame known as the Kay > Behrensmeyer Site. This volcanic tuff has become known as the KBS Tuff. > > At East Rudolf, the KBS Tuff is of utmost importance. First, although > human fossils and artifacts cannot be directly dated radiometrically, > the KBS Tuff can be Second, artifacts (tools) have been found in close > association with the KBS Tuff. The assumption is that the date of the > tuff gives an estimate of the age ofthe stone tools. Third, hundreds of > homo and australopithecine fossils have been found either above or below > the KBS Tuff. Of all the fossils found in association with the KBS > Tuff, skull 1470 is the most important. > > Although the KBS Tuff is volcanic in origin, it is not a primary airfall > tuff. That is, it was not deposited directly on the land. Lake Rudolph > was much larger at that time. Some ash fell into the lake. Some was > carried by rivers into the lake. Thus, the KBS Tuff has been > transported by and deposited from water. For this reason it has a great > deal of foreign material in it, making it very difficult to get pure > samples for dating. And I should think that ought to give us the key to the controversy. It is difficult to purify so-called juvenile samples (those produced by the eruption) from contamination with samples which are older, which were picked up during the deposition of the tuff by water. Thus, we get 27 million year ages (Miocene) and 500 million year ages (Cambrian) mixed in. This point is discussed in Gleadow's article on fission track dating (34-35). > The first attempt to date the KBS Tuff was a feasibility study done in > 1969, several years before the discovery of skull 1470. Leakey supplied > samples to F.J. Fitch and J.A. Miller, recognized authroities at that > time in potassium-argon (K-Ar) dating. Many species of mammals had been > found below the KBS Tuff, as well as australopithecine fossils and human > artifacts. It was imperative that these discoveries be placed in their > proper chronological setting. > > In their report in 'Nature,'(1) Fitch and Miller first commented on the > many possible sources of error in dating. "One of the most intractable of > these," they said, "is the possible presence of extraneous argon derived > from inclusions of pre-existing rocks."(2) To check for this extraneous > argon, they first dated the raw rocks as they were originally submitted > by Leakey. Their analysis gave dates from 212 to 230 Mya. "From these > results it was clear that an extraneous argon age discrepancy was > present...."(3) > > The first question an outside observer would ask is, How did they know?! > The answer is that the fossils told them so. In spite of our being > assured that the dating methods constitute an 'independent' confirmation > of evolution, the fossils had already determined the outside limits for > the dates that would be "acceptable." Based on their alleged evolution, > the australopithecine and other mammalian fossils found beneath the KBS > Tuff had pre-determined that the rocks should be somewhere between 2 and > 5 myo. Anything beyond that was "obviously" the result of "extraneous > argon." > > Dates of 212 to 230 MYA were notoriously far off. These dates would > place the KBS Tuff in the Triassic period of the Mesozoic era, which is > early dinosaur times. Everybody knows that Dinosaurs and Hominids were > not contemporary, hence it is obvious that these dates were wrong. > Without the fossils, however, there would be no way for a geologist to > know if these were GOOD dates or BAD dates. Under other circumstances > and no fossils, the geologists could well have accepted these dates as > GOOD dates. When fitting rock layers into their "proper sequences" over > large geographic areas, it is evolution and the fossils that guide the > geologists -- not radiometric dating. The above three paragraphs are complete bosh. Let me quote from the same article (1-5): "One of the most intractable of these is the possible presence of argon derived from inclusions of pre-existing rocks. Peliminary petrographic examination of the tuff sample revealed it to be a crystal-vitric-tuff rich in small pieces of pumice and minute crystal fragments set in a matrix of devitrifying volcanic dust. While much of this pyroclastic material was obviously juvenile, the presence of microcline suggested possible contamination from the wall rocks of the vent. The fine grain-size prevented effective separation of juvenile and possiblynon-juvenile components, and an exploratory conventional total rock K-Ar age determination was made finally on the washed and mixed 30/50 mesh fraction of the crushed sample." In other words, BEFORE doing the age determination, they LOOKED AT the sample they were supposed to age, and what they SAW was a mixture of the real stuff (juvenile) and older contaminants (non-juvenile). But they did a preliminary age determination anyway just to confirm whether or not there were contaminants, and they got those 200 million year ages. How did they know those were wrong? By inspection of the rocks beforehand. Something geologists are specially trained to do. > To compensate for this "obvious error" in dating the KBS Tuff, Fitch and > Miller stated: "... it would only be possible to date this tuff by > careful extraction of undoubtedly juvenile components for analysis."(4) > In other words, Fitch and Miller then proceeded to remove from the > whole-rock samples those components of the rock which they believed were > "undoubtedly" juvenile or young, that showed no sign of weathering or > alteration. The observer can be forgiven if he asks another question, > How do they know for sure which components of the rock are undoubtedly > young?! Juvenile, in this context, does not mean "young" per se, but means laid down when the tuff was laid down. It means, solidified, crystallized, at that time, rather than long before. Older detritus would have been carried, in this case, by water, after having been exposed, say, by erosion. So weathering would be one way. Or, to quote Hurford and Gleadow (23-24), describing how they tell the difference with zircon crystals: "95% [of these zircons] are colourless, water-clear unzoned euhedral crystals.... they must be regarded as juvenile crystals, primary to the eruption of the enclosing pumice. Approximately 5% of the zircons are variable in form and much darker in color... light brown to red, often strongly zoned and have a very rounded form, with no discernible crystal faces or inclusions. Since these crystals all have high spontaneous fission-track densities, they appear to be old, detrital zircons...." Of course, high fission-track densities compromises the independence of this assessment, somewhat. But not so much, if you have a history of successful fission-track dating behind you. > Thus began the long process, based upon evolutionary and other > philosophical assumptions, by which the geochronologist manipulates or > "messages" the data to guarantee that he gets a GOOD date. I want to > stress that the geochronologist does this in absolute sincerity. He is > so committed to evolution and its attendant age demands that he believes > implicity that he is just removing error from his data to arrive at > truth. The obvious subjectivity in it escapes him. It is a perfect > illustration of circular reasoning in an experimental frame of > reference. The experimenter manipulates the data to guarantee that he > gets the results that is NEEDED. In computerese its GIGO. I'm a little concerned here with the consistency of Lubenow's argument. These are the investigators who go on to produce dates which are too old for the comfort of evolutionary theorists. Of course, when they wrote the article (1970), Leakey had not yet found his skull 1470 (that happened in 1972). So I won't press the point. > Experiments were conducted seperately on "fresher" pumice and feldspar > crystals, using thre different processes: K-Ar age determination, > 40Ar-39Ar total degassing and 40Ar-39Ar age spectrum. Fitch and Miller > concluded that the KBS Tuff was "very close to 2.6 myo."(5) This figure > of 2.61 mya was widely published in the scientific and popular press. > Leakey stated that 1470 was found below rock that was "accurately > dated"(6) and "securely dated"(7) at 2.6 mya. > > In 1972, before skull 1470 was discovered (or at least before it was > announced), Vincent Maglio published in 'Nature'(8) a chronology of the > hominid-bearing sediments east of Lake Rudolf which included the KBS > Tuff. His work was based upon the vertebrate faunas. The lineages were > of two species of pig (suid) and one species of elephant. Although > there were some problems, Maglio's dates for the sediments were > somewhat compatible with the radiometric date arrived at by Fitch > and Miller, and were considered at the time to confirm their > date. "Somewhat compatible" is, in the context of this discussion, misleading. Maglio's pig date for 1470 is 2.0 Mya, consistent with the final date of 1.9 Mya for the KBS tuff. Maglio's elephant date is 2.5 Mya, about .4 My too young for 1470. Lubenow's strategy is to make it appear that everyone had reached consensus on the older dates at this time, then show everyone changing their minds together. This simply didn't happen. > In 1974, a third chronology of the area was published in 'Nature'(9) by > Brock and Isaac. The study was based on the paleomagnetism of the > deposits below the KBS Tuff utlizing 247 samples. They stated their > conclusions for the group of fossils including skull 1470 as follows: > "An age of 2.7 to 3.0 myr for this group is strongly indicated."(10) > Since this date referred to the sediments that the skull 1470 was > actually found in, and the KBS Tuff dated at 2.61 myr lies above the > fossil, it seemed to represent a "bulls-eye" for the correlation of the > various dating methods. The heading of the article stated that their > measurements "povide a valuable check on other dating methods."(11) > Later they said that because the isotopic and paleomagnetic ages were > consistent, "...this independent evidence greatly strengthens our > proposed chronology."(12) > > However, Brock and Isaac also made the following comment: > > The correlations shown in Figure 4 are not fully independent, > and rely partly upon K.Ar and faunal evidence as well as upon the basic > polarity data. > > The starting poing for the correlation is the age of 2.61+/-0.26 > myr obtained by Fitch and Miller from selected sanidine crystals from > pumice specimines from the KBS Tuff.(13) > > This comment indicates that the correlation by Brock and Isaac was not > as independet of the other dating methods as they claimed it to be. Expecting it to be completely independent is Lubenow's version of science fiction. Magnetic polarity reversal correlation takes the known history of polarity reversals (which has been documented all over the world and checked against radiometric datings) and tries to see which part of that history matches up with a given series of local strata. Unfortunately, local strata generally cover only a small fraction of polarity reversal history, and there might be more than one pattern of matchups. Not to mention other problems -- see Brock's article (with Ndombi, Cos, Hillhouse, refs. 28-29) for more details. HOWEVER -- if other dating methods limit the range of match-ups, magnetic polarity history might help decide among a handful of different possible dates. So I'd call this partial independence. > Also in 1974, Anthony Hurford attempted to date the East Rudolf > sediments using still another method: fission-track dating involving > uranium. His purpose was to check out an unpublished study by Fitch and > Miller that suggested that vast portions of the East Rudolf sediments > had been changed or altered by volcanic heat or hot ground water around > 1.75 mya, causing partial or complete overprinting of the apparent ages > obtained from them. > > Herford's conclusion regarding his fission track specimen: > > The specimen has either suffered no thermal annealing or that it > has been totally annealed at 1.8 myr. > > As this tuff is within the Kubi Algi Formation and is > stratigraphically below the 2.6 myr KBS Tuff, the second alternative is > accepted as the correct interpretation.(14) > > He agreed with Fitch and Miller that the sediments had been altered at > about 1.75 to 1.8 mya. One could be excused for asking why the > annealing of the lower sediments at 1.8 mya did not call into question > the KBS Tuff date of 2.6 mya. To quote from Hurford (14): "... fission tracks in glass are particularly susceptible to thermal annealing." But my technical expertise doesn't extend far enough for me to suggest that perhaps it effected Hurford's sample more than Fitch and Miller's. Second point: as a matter of fact, this annealing event (otherwise referred to as the overprinting event) DID affect Fitch and Miller's measurements. See (23-24) -- they did what's called an age spectrum analysis and found so-called "plateaus" at 1.94 Mya and 2.46 Mya. The former plateau, according to them, corresponded to the overprinting event. > A study of Hurford's methodology illustrates how dogma finds its way > into science. He started by referring to the date of the KBS Tuff as a > "firm date." Apparently the date became firm because he felt that it > was supported by the fossil and paleomagnetic evidence. He did not > mention that the fossil correlation was only of the most general sort > and that the paleomagnetic date was based on the radiometric date. In Once again: it is misleading to say the paleomagnetic date was based on the radiometric date. The paleomagnetic date was consistent with it. This consistency tended to support both determinations. > spite of an obvious need for caution, Hurford's acceptance of the KBS > Tuff date became the benchmark on which he based his fission-track > conclusions. It was NOT a benchmark in calibrating his experiment, or producing any results. And his results did seem to imply that SOMETHING happened to his specimen 1.8 Mya. The question is, what? Given Fitch and Miller's prior results, suggesting an overprinting event, Hurford's conclusion was perfectly reasonable. But, in any case, Hurford's value of 1.8 Mya was completely independent of any other dating methods. > It seems, however, that Hurford set up a strange scenario that would > certainly seem to compromise the "firm date" of the KBS Tuff. At any > rate, it is clear that the various dating methods are related, and the > dates obtained are not independent of one another. Once again: the numbers obtained are not related, just the interpretation of the numbers. And, correct, Hurford's date did represent a problem. > Late in 1974, Fitch, Miller and associates published the results of > their revised study confirming their original dating of the KBS Tuff at > 2.61+/-.26 mya. Refring to the other studies, they stated: "The > compatibility of independent evidence is a very strong argument for > accepting the chronology now proposed for EastRudolf."(15) However, we > have seen from the other studies that they are not independent but were > linked to the original radiometric date by Fitch and Miller. Bosh. We have seen nothing of the kind. Let me quote the two preceding sentences. "This dating work on rocks from the East Rudolf Basin, completed in 1973, confirms the suggested age of 2.61+-0.26 Myr reported for the KBS tuff in 1970 and places it securely within a chronologically satisfactory sequence of dated tuffs. Our conclusions are compatible with palaeomagnetic polarity reversal results from sedmiments and tuffs in the basin." (1) The article quoted reviews dates on various tuffs stratigraphically above and below the KBS tuff, at 1.32, 1.48, 1.57, 2.61, and 3.18 Mya. The date for the KBS tuff fits in consistently with these other dates (though the later date, 1.9 Mya, fits in too). (2) By "independent" what is meant here is that paleomagnetic measurements were carried out independently of the radiometric dating, and yielded the expected direction and reversal pattern consistent with the age of 2.61 My. Paleomagnetic polarity reversal results were not sufficient to determine the age, but were in agreement with it. > By late 1974, two years after skull 1470 had been presented to the > world, the KBS tuff had been dated five different times by four > different dating methods. The alleged compatibility of the four > different methods would seem to make all of this a geologists's dream. > What better proof could one want for the reliability of the various > dating methods to furnish independent confirmation of the dates for the > fossil material? Leakey had found the world's oldest fossil belonging > to the genus Homo. On the surface all seemed serene. I don't see anything in the references to support this exaggeration. The actual date was obtained by ONE independent method -- K-Ar dating. Read everything I have said before: paleomagnetic data was consistent with this, fission track dating did not support this, pigs would have snorted, and elephants would have mildly trumpeted. This is Lubenow's strategy again: make the date seem secure as possible, then tear it down. > However, under the surface paleoanthropology was seething in ferment. > Skull 1470 with its estimated date of 2.9 mya presented the evolutionary > world with an intolerable situation. Leakey did not exaggerate when he > declared: "Either we toss out this skull or we toss out our theories of > early man."(16) The problem wasquite simple. Human evolution did not > allow for a skull so modern in morphology to be that old. It was > absolutely predictable to those of us who watched these matters unfold that > something would have to give. Only three things could happen to relieve > the stress that the theory of human evolution was experiencing: 1) the > date for 1470 could be revised; 2) 1470 could be asigned to the most > distant and primitive form of Homo; or 3) 1470 could be reevaluated and > designated an australopithecine. Actually, all three of these solutions > happened in one way or another. The date was eventually revised, the > fossil was asigned to the category Homo habilis, and some said that 1470 > was actually an australopithecine. Misleading. Suggests that Homo habilis was invented for this fossil. It was not. Homo habilis was already known. See Leakey's article (ref. 7). And, yes. Something would have to give. So? > Leakey, however, continued to fight for the original date. Although he > was committed to evolution and was aware of the problem the date for Committed to evolution? Lubenow is being tendential here. Leakey was, at most, committed to one particular chronology of human evolution. Though his insistence on the earlier date belies that contribution. > skull 1470 presented for evolution, his situation was somewhat > different. He was considered the discoverer of skull 1470. > [snip] > > While Fitch and Miller were busy confirming their original results, > still another study was already underway by G.H. Curtis and associates. > They used K-Ar dates on pumice and arrived at dates of 1.6 and 1.82 mya. > These dates were considerably younger than the dates the five previous > studies had reported. > > Commenting of the broad scatter of results Fitch and Miller had obtained > earlier, they gave this explanation: > > Contamination by ancient bed rock material during the reworking > of the tuffs was suggested to account for the anomalously old dates, > whereas subsequent alteration, 'overprinting,' of the pumice fragments > used for dating, by alkaline-rich and possibly heated ground water may > explain the anomalously young dates by partial loss of radiogenic > argon.(17) > > Since the whole point of their exercise was to establish the age of the > KBS Tuff, the question again must be asked, "How did they know that the > older dates or the younger dates were anomalous? Anomalous with > reference to what? It was obvious that it had already been determined > what the "proper" age should be. How was this determined? By the > concept of evolution. The age of the KBS Tuff and of skull 1470 must be > lowered. I don't think that's the whole point of the paragraph quoted. They were mainly commenting on the scatter. Clearly, when there is scatter, there are anomalous values. Furthermore, if the values are too high, they will conflict with that tuff stratigraphically BELOW the KBS, dated at 3.18 Mya. If too low, they will conflict with that tuff stratigraphically ABOVE the KBS, dated at 1.57 Mya. Furthermore, as I said, simple inspection of these tuffs revealed that they were carried by water, and loaded with older detritus. Finally, what's wrong with suspecting the 2.61 Mya date is wrong, on the basis of the accepted chronology of human evolution? If there is a conflict here, then either (1) the date is wrong, or (2) the chronology is wrong. We still don't know which. So, if the chronology is already supported by independent evidence, then it is natural to test the 2.61 Mya date to see if it can be reproduced. > The Curtis article challenged the validity of the 40Ar-39Ar technique > for this paricular dating situation and criticized the methodology of > Fitch and Miller. It further stated that "...older pumices may also be > present in the KBS Tuff horizon which sould account for the 2.61 myr > date reported by Fitch and Miller."(18) Criticizing the samples used by > Fitch and Miller, the dating method employed by Fitch and Miller, and > the laboratory technique of Fitch and Miller left little more to be > said. > > All of the above-cited articles spoke of the great difficulty in getting > rock or crystal samples that were not altered, weathered, or derived > from older rock. Curtis et al. explained at length their efforts to > extract from the whole-rock samples the portions that were suitable for > dating. However, Fitch and Miller also went to great lengths to extract > suitable samples. The question arises, How does one know when one has > good samples for dating? The only answer to that question is that > "good" samples give dates that are in accord with evolutionary > presuppositions. "Bad" samples are the ones that give dates not in > conformity with evolution--a classic illustration of circular reasoning. Absolutely false. Right in the beginning of this whole process, in their first article, Fitch and Miller said (as you'll remember) that an inspection of the samples BEFORE dating showed that there were non- juvenile particles mixed with juvenile ones. Remember those 200 Mya dates? > Curtis et al. also mentioned the factor that would ultimately determine > the date of skull 1470: the evolution of the pigs. > > [When some palaeontologists compared fauna associated with] the > KBS Tuff in East Rudolf with those of other, supposedly well calibrated > localities, the reliability of the date of 2.61 myr for the KBS was > questioned. Although Maglio found that the morphology of elephant > fossils fit with a 2.5 myr date, Cooke and Maglio, in 1972, pointed out > that fossil pigs from below the KBS Tuff horizon at East Rudolf seemed > to correlate best with those from beds dating close to 2 myr in the Omo > River area to the north in Ethiopia.(19) > > Notice that elephant evolution fit the older date, but pig evolution fit > the younger date. The pigs would ultimately win. This does not support > the idea of concordant results that evolutionists talk about. Let me point out again: the 2.5 Mya date for elephants is for elephants BELOW the KBS tuff. I could imagine a better fit for elephants. > It is fascinating to see that Curtis et al. claimed authority for their > dating results because of the high degree of correlation within their > study. But that same claim was made for the older date. Also, five > different dating projects involving four different dating techniques all > supposedly agreed on the older date within reasonable margins of error. Once again, this statement is simply false, given the references listed at the bottom. Only K-Ar actually produced numbers. Only magnetic polarity reversal data was consistent with K-Ar dating. If anyone has read more from that early period, they can perhaps supply better information on this. > The 28 October 1976 issue of 'Nature' contained not one but two dating > projects for the KBS Tuff by two different methods. These two methods > seemed to agree on an older date for the tuff and hence for skull 1470. > > The first of these studies was by Fitch, Miller and Hooker. They first > recalculated the results of their 1969 work and told why: > > Developments in the analytical techniques of 40Ar-39Ar dating > since then enable recomputation of the results obtained, using, in > addition, a more accurate value for the constant of proportionality (J) > used in the 1969 experiments.(20) > > Recalculating with 1969 rock samples and utilizing both the K-Ar and the > 40Ar-39Ar methods gave them a revised estimate for an age of 2.42 mya. > Calculating with rock samples obtained in 1971-73 and using only the > 40Ar-39Ar technique gave aminimum age of 2.4 mya. The close correlation > of these two dating efforts by different techniques gave them confidence > in the accuracy of their results. > > Fitch, Miller, and Hooker acknowledged the controvery that was raging > because ofstone tools found and one very human-looking fossil: > > Over the past five years, opposition to the acceptance of a 2.5 > myr age for the KBS Tuff has come from three sources: first, > archaeologists and paleoanthropologists disturbed by the consequent > antiquity of hominid fossils and stone tools found close to or > associated with the KBS Tuff; second, palaeontologists reporting > apparent misfits between the faunal sequences at East Rudolf and > elsewhere; and third, from a small programme of conventional total > fusion K-Ar age determinations on East Rudolf pumice samples undertaken > at Berkeley.(21) > > The "small programme" at Berkeley is a reverence to the work of Curtis > et al. who dated the KBS Tuff at 1.6 and 1.82 myr. The flaw in that > date is quite obvious to Fitch, Hooker, and Miller: > > ...K-Ar apparent ages in the range 1.6-1.8 myr obtained from the > KBS Tuff by other workers are regarded as discrepant, and may have been > obtained from samples affected by argon loss.(22) > > This exercise can appropriately be named the dating game. Since yours > is obviously the correct date, those who arrive at a younger date had > samples that obviously had experienced argon loss. A date older than > yours can be explained if you declare that those samples had obviously > inherited excess argon from older rock. How does one refute that kind > of logic? [That's logic?!] Using isochron methods you can eliminate the possibility of argon gain/loss. Curtis et. al. found good isochrons for their younger date. Fitch and Miller found a good isochron for their "age spectrum plateau" yielding the older date. I'm not sure what the explanation is, but when you get an isochron this indicates you're dating SOMETHING. So I'd say it's the detritus problem again. > The second problem, "apparent misfits between the faunal sequences," > will eventually be settled rather arbitrarily by a victory of the pigs > over the elephants. Where else but in the world of science fiction > could such a confrontation of pigs and elephants have such unlikely > results? > > It is the third problem that is most revealing. It involves > archeologists who are "disturbed by the consequent antiquity of hominind > fossils and stone tools found close to or associated with the KBS Tuff." > 'Disturbed' seems a strange word to describe scientists who are supposed > to let the facts speak for themselves. I would think that words like > 'interested,' 'amazed,' or 'intrigued' would be far more appropriate. > 'Disturbed' sounds like they felt threatened. They were. The whole > concept of human evolution was on the line. This was the real issue > behind a controversy that raged for ten years over some ash out of a > volcano in East Africa. > > One more item needs to be mentioned. Fitch, et al. commented that the > Berkeley group reported 'scatter' in their dates ranging from 1.5 to 6.9 > myr. Fitch et al. reported their own scatter in apparent ages ranging > from .5 to 2.4 myr. In > some cases the scatter was interpreted as overprinting events. In other > cases, 'naughty' crystals were removed to give results more appropriate > to the overriding principle behind it all -- human evolution. This is a total distortion of the Fitch et. al. article. The closest thing I could find to a reference to removing "naugthy crystals" is: "Each of the samples was a cleaned and acid-washed feldspar crystal concentrate extracted from pumice by hand picking only the most obviously juvenile crystals from sawn slabs of pumice beneath a binocular microscope." If these crystals were naughty, Fitch et. al. knew they were beforehand. A serious discrepancy, however, still remains, since the process of hand-picking juvenile crystals led to different ages, depending on the experimenter. But even this is not as serious as you might think. If we suspect that what we think are juvenile crystals might not be juvenile, then we simply keep trying to pick out juvenile crystals again and again. Eventually, if what we thought was juvenile was older detritus, we'll run into some juvenile crystals, and age determination will yield successively lesser values, approaching some limit, which is the time of the eruption. And that limit has been reached -- 1.88 Mya. > The other article in that 28 October 1976 issue of 'Nature' was written > by Hurford, Gleadow and Naewer. It was about fission-track dating of > zircon crystals found in the KBS Tuff. They began with a rather > remarkable statement regarding the K-Ar and 40Ar-39Ar dating methods: > > K-Ar and 40Ar-39Ar dating techniques have been applied to >100 > rock and mineral samples from East Rudolf, but interpretation of the > dates determined by these methods has not been straightforward. > Geological and analytical factors have been postulated to explain the > scatter of K-Ar and 40Ar-39Ar apparent ages obtained from volcanic > sanidine-anorthoclase crystals separated from pumice cobbles in the > tuffs.(23) > > The authors did not imply that the radiometric dating workers were being > dishonest. They did say that the interpretation of the dates involves > hypothetical and philosophical assumptions that have a bearing on the Nowhere in the entire article do they say this. They don't mention any "assumptions" beyond the "geological and analytical factors" referred to in the quote above. Indeed, they supply evidence, in their determinations, for the inclusion of detritus in the tuff. Recall that article mentioned earlier distinguishing zircon grains? This is the one. And they actually dated three of the discolored, presumably non-juvenile grains. The results? 303 Mya, 380 Mya, 293 Mya. Recognizing such grains, and confirming that they are older, is hardly making "hypothetical and philosophical assumptions." > results. (This, by the way, is exactly what creationists have been > saying about all radiometric dating methods.) They also stated that > their study was conducted because of the apparent conflict between the > K-Ar and 40Ar-39Ar dating methods -- something that was played down in > previous studies. Misleading. There was never a suggestion of a conflict between methods, thus nothing to be "played down." Curtis et. al. used conventional K-Ar, Fitch et. al. used conventional K-Ar AND 40Ar-39Ar methods. The problem, as it was usually emphasized, was a conflict between results obtained by different experimenters. > Their conclusion was that the KBS Tuff has a date of 2.44 myr. This was > very close to the estimate of Fitch et al. published in the same issue > of 'Nature.' After describing their methodology they said: > > Using these techniques and a value for the 238U spontaneous > fission decay constant of 6.85x10(-17) yr(-1) we have obtained ages on > standard zircons which agree very closely with their independently known > ages.(24) > > This remarkable correlation of dates involving two independent dating > techniques seemed to confirm all that the general public has been led to > believe -- that the dating methods can be trusted because independent > methods give the same results. > > However, in the 16 June 1977 issue of 'Nature' appeared a letter from > Wagner of the Max Planck Institute. Wagner maintained that there is > uncertainty as to the spontaneous fission constant of uranium 238, and > that Huford et al. should have used a different constant: > > ...Many fissioon-track specialists no longer use the > 6.85x10(-17)yr(-1) value, but now use as the decay constant > 8.46x10(-17)yr(-1); there are good reasons for this preference. If this > higher value for the decay constant is used, the fissioon-track age of > the pumice in the KBS tuff recalculates to 1.98 myr, which would lend > support to the K-Ar age measured by Curtis et al.(25) > > Huford et al. defended their use of the uranium 238 constant by saying: > > When it is used in conjunction with the fission track glass > standards of the U.S. National Bureau of Standards, we get the best > agreement with the K-Ar ages of co-existing minerals and we use it for > this reason.(26) > > In other words, the true value of the spontaneous fission constant of > uranium 238 is unknown. At least two values are currently in use. In > matters of fission-track dating, one is thus free to use the value that > gives him the answer he is looking for. One can make the age of the KBS > Tuff agree with either Fitch or Cutis, whatever one's pleasure might be. Bosh. One uses the value one believes has been empirically determined. Or is Lubenow suggesting that Hurford et. al. calculated their ages first using 6.85x10(-17)yr(-1), then using > 8.46x10(-17)yr(-1), then selected the value of the constant that gave them 2.44 Mya? Also note: the later fission track dating in Gleadow et. al. uses the same Hurford value 6.85x10(-17)yr(-1), and gets the Curtis et. al. date of 1.9 Mya. So Lubenow's implication (perhaps not intended) that later fusion-track dating switched to the other constant value is misleading. > The difference in the two dates is almost half a million years in > dealing with a date of only about two and two-and-a-half million. That > hardly seems like precision dating. > > Because they tended to confirm the older date for the skull 1470, these > two studies put more strain on the evolutionary establishment. Hurford > et al. wrote: "Curtis has described the original 2.61 myr date for the > KBS Tuff as being much questioned in private anthropological and > paleontological circles."(27) Since anthropologists and paleontologists > do not normally have technical expertise in the radiometric dating > methods, they were not challenging the methodology or the assumptions of > the dating methods. They were rejecting the older date solely because > of its philosophical implications. The problem was the modern No, no, no. Paleontological implications. > morphology of KNM-ER 1470 versus the demands of human evolution. > > A new study on the paleomagnetism of the Koobi Fora Formation was > published in early 1977. It acknowledged that the previous > paleomagnetic study had used "... the previously published age of > 2.6+/-0.26 myr for the KBS Tuff as a fixed point..."(28) The study > cited additional peleomagnetic results as warrenting a reevaluation of > the magnetic stratigraphy. > > The study gave two different interpretations of the data based upon the > two different suggested ages of the KBS Tuff. It clearly revealed that > dates arrived at by paleomagnetism are not independent confirmations of > other dating results but are closely tied to the rediometric results > they use as a starting point. Since the KBS Tuff is the top unit of the > lower member of the Koobi Fora Formation, the following quotation > reveals how different the results can be when different tarting points > are used in this dating game: > > In both interpretations the age of the upper member, which lies > above the KBS Tuff, is between 1.2 and 1.8 myr; however, the age of the > top boundary of the lower members differs by 1 myr.(29) Lubenow misunderstands how the paleomagnetism results are being applied. Matching up a local formation (with a short geological history, short = just a couple million years) with magnetic pole reversal history is an iffy venture. The fact that there are two different fits, one agreeing with the 2.6 Mya age, gives confirmation to that age. However, the fact that the other fit agrees with the 1.9 Mya age gives equal confirmation to that age. At least the paleomagnetic data is not inconsistent with these age determinations. > Around 1976, the name of Lake Rudolf was changed by the Kenyan govenment > to Lake Turkana. This change has been a fruitful source of confusions, > since the fossils recovered east of the lake continue to carry the > designation East Rudolf, whereas fossils recovered from west of the > lake, representing more recent work, carry the designation West Turkana. > Up to now we have consistently used the name Lake Rudolf. From now on, > we will use the newer name Lake Turkana. > > On 20 March 1980, two more dating studies on the KBS Tuff appeared in > the pages of 'Nature.' Remember that two earlier studies -- one on > fission-track dating of zircons and one on 40Ar-39Ar dating of > orthoclase crystals -- agreed closely that the age of the KBS Tuff was > 2.4 myr. They cited the close correlation of two independent dating > methods as validating their accuracy. Now, two studies -- one on > fission-track dating of zircons and one on K-Ar dating of orthoclase > crystals -- agreed closely that the age of the KBS Tuff is 1.87 or 1.89 > myrs. They also cited the close correlation of two independent dating > methods as validating their accuracy for the revised date. The new > fission-track study was by Gleadow. The K-Ar study was by McDougall, > Maier, and Sutherland-Hawkes and Gleadow. Then in late 1981, McDougall > published in 'Nature' his 40Ar-39Ar study of the KBS Tuff, giving a date > of 1.88 myr. At that point, the ten-year controversy over the date of > the KBS Tuff came to a close. Concordance on the more recent date had > been achieved. > > At first glance, it would seem to be a tremendous victory for evolution > and the uniformitarian dating methods. We know that science often > proceeds by trial and error and by controversy. The fact that an > amazing correlation between the pig evidence and three different dating > methods had been achieved should be something to celebrate. The dating > of the KBS Tuff was now a nonissue. Yet, there were factors that demand > a closer look at the situation. > > The Power of Pigs > > The dating of the KBS Tuff was not settled in 1980 and 1981 by the > conformity of three different dating methods. The controversy was > actually settled in 1975 by the pigs. Donald Johanson tells of > attending the Bishop Conference on anthropology and geology in London. > The dating of the KBS Tuff and its implications were major topics of > conversation. Glynn Isaac, who accepted the older date, arrived with a > 'pig-proof helmet' to protect him against the pig men. > > A major paper was presented by B. Cooke, who had studied the pig > sequences at Omo, at Hadar, and at Olduvai Gorge. According to Cooke, > the dating at Lake Turkana, based on the dating methods, was off by > about 800,000 years. The pigs at Turkana told him so. He even wore a > tie with the letters MCP woven into it. They stood for 'male chauvinist > pig,' but Cooke claimed that they really stood for 'Mesochoerus > correlates properly.' Johanson wrote of the 1975 conference: 'Nearly > everyone but the Lake Turkana team [Leakey and associates] went away > convinced that the KBS tuff and the skull 1470 dates would have to be > corrected.'(30) > > Astounding about the whole affair was that the anthropologists were > rejecting the same objective, scientific data that they universally > appeal to. At that time the radiometric evidence for the older date was > very strong. There was internal consistency within the studies, and a > high degree of conformity by five different dating techniques. The main > thing the dates did not conform to was the concept of the evolution of > pigs and of humans. > > The evolution of the pigs is said to be the clear-cut answer to the > dating problems at Koobi Fora as well as elsewhere in East Africa, but > the evidence is less than impressive. In his phylogeny of the pigs, > Cooke presented family trees for three taxonomic groups.(31) Two of the > groups have at their bases the phrase 'hypothetical Sus-like ancestor.' > The twenty species that make up these three groups are all shown in > parallel lines connected only by dotted lines, indicating that there is > no known relationship between any of the species. The parallel-line > chart could just as well have been drawn by a creationist. Sorry, but there are intra-specific progressions which can be used for dating. > > Most of the fossil-pig evidence consists of teeth. several species are > based on the skimpiest of evidence ('imperfectly known,' 'rare,' > 'scarce') and the various relationships are largely judgment calls. > Terms such as these appear: > > is probably ancestral > seems to represent > suggest that ... evolved independently > must at this stage also be giving rise to > probably ancestral to > suggests a derivation from > may have branched off > almost certainly branched off from > demand descent from a common ancestor > > Cooke's article was written in response to one by White and Harris.(32) > Cooke had three taxonomic groups while White and Harris had four. There > are differences in the two taxonomies, but Cooke maintained that they > were of no great moment. He then went on to explain why species that > White and Harris had grouped together should be separated, and vice > versa. This creation and annihilation of species by the whim of the > taxonomist 'due to our having different basic philosophies on te nature > of species in paleontology'(33) reveals how plastic and subjective this > science is. I am not minimizing the difficulty of the species concept > in paleontology, nor am I debasing the attempt to sort things out. I am > merely stating that the authority with which paleontologists make > dogmatic statements about the evolution of the pigs is not warrented by > the facts. As in every other area of paleontology, a great deal more > humility would be appropriate. This entire paragraph is a non sequitur. Whatever judgment calls are required to establish phylogeny, none are needed to establish differences, and when differences are correlated with strata, differences alone are sufficient for dating. Secondly, Lubenow is indulging in typological thinking here, rather than populational thinking. The species concept is plastic, and that's no accident, because you can't draw definite lines between species in lineages. E.g.: even if we reject evolution, we can still date a formation as Cretaceous if we find a Tyrannosaurus in it. (Unless, of course, we also find an Ichthyostega in it.) On the other hand, the extrapolation of trends was used in the original Maglio article (8). And I couldn't find the Science 201 Cooke article, so I can't assess the validity of some of Lubenow's statements about it. Anyone else have a comment? > The 1980 and 1981 studies on the date of the KBS Tuff contained so many > criticisms of all of the earlier studies that they called into question > the objectivity and validity of the dating methods themselves. Gleadow > began the process: > > K-Ar evidence of Curtis et al. suggesting that tuffs mapped as > the KBS in area 105 and 131 were of slightly different age, has now been > eliminated with the discovery of a systematic error in the lower (1.6 > myr) ages.(34) To say this calls into question the objectivity of the method, without telling us what the systematic error was, is pure posturing. > After demonstrating the presence of contamination in all of his own > samples, and the extreme difficulties in dating zircons in the 1-3 myr > time span, he continued: > > It therefore seems highly likely that feldspars separated for > K-Ar dating could also contain traces of much older basement feldspar. > This supports the contention that older K-Ar and 40Ar-39Ar ages are the > result of contamination. As discussed above, the fission track ages of Once again, that inclusion of detritus was a problem known from the first. > Hurford et al. are thought to be too old for purely analytical reasons, > in particular the mis-identification of a finite number of acicular > inclusions or dislocations as tracks and possibly a biased choice of > grains for counting.(35) Significantly, they redated a sample from Hurford et. al., and came up with the younger age. > In the same issue of 'Nature' was the report of a study by McDougall et > al. on the K-Ar dating of the KBS Tuff. They began by confessing that > 'Conventional K-Ar, 40Ar-39Ar and fission track dating of pumice clasts > within this tuff have yielded a distressingly large range of ages.'(36) > > After explaining that Fitch and Miller actually reported results ranging > from 0.52 to 2.64 myr in one set of concentrates and ages from 8.43 to > 17.5 myr on another clast before settling on a 2.61 myr date which they > later revised to 2.42 myr, they also explained how Curtis et al. arrived > at their 'concordant' ages: > > Disregarding four conventional K-Ar ages on feldspar from pumice > clasts in the KBS Tuff in the range 2.01-6.9 myr, thought to be caused > by detrital contamination, Curtis et al. obtained concordant K-Ar ages > on feldspar and glass from pumice clasts found in this horizon with mean > value of 1.82+/-0.04 myr and 1.6+/-0.05 myr in two different areas, > respectively. Subsequently, Drake et al. reported an error in potassium > determinations on the samples previously dated by them that yielded the > 1.6 myr ages.(37) > > McDougall et al. then stated how 'remarkably concordant' their own dates > were at 1.9 myr after removing from consideration samples that gave ages > of 4.11 and 7.46 myr. They explained these anomalous ages as follows: > > We attribute these poorly reproducible ages to the presence of > variable but small amounts of old detrital K-feldspar in the aliquants > used in the argon extractions. *Careful petrographic examination of the > mineral concentrate, however, did not lead to positive identification of > detrital K-feldspar.* Nevertheless, there is no doubt that old detrital > material was being brought into the East Turkana Basin during deposition > of the sediments.(38) > > With this clear victory of philosophy over observation, they then used > the concordance of their results and agreement with the results of the > study by Gleadow to give validity to their date for the KBS Tuff. Okay. It's already known that there is a problem with contamination. Then McDougall et. al. get ages of: 1.90, 1.89, 1.99, 1.97, 1.86, 1.87, 1.88, 2.00, 1.90, 1.89, 1.89, 1.89, 1.87, 1.88, 1.90, 1.87, 1.88, 1.91, 1.89, 1.88, 1.87, 1.90, 1.93, 1.89, 1.94, 1.87, 1.90, 1.86, 1.90, 7.46, 4.11 Mya. (I'm quoting these values from the article.) So, does it look like the elimination of two anomalous values (obtained, by the way, from two independent measurements of the same sample) is special pleading? Lubenow would never make it as a scientist. > Since the fission-track dates and the K-Ar dates of the KBS Tuff had now > been reconciled with the date demanded by the evolution of the pigs, the > only remaining problem was the high 40Ar-39Ar dates that Fitch et al. > had reported. McDougall solved this problem in 1981. He reported that > in some of his work there was a greater scatter of data points than > could be explained by experimental error, and that in the step-heating > experiment it was necessary to exclude some data. > > Plateau and regression ages are derived using all data from each > step heating experiment, as well as by excluding results from steps that > give discordant ages. The criterion for exclusion of a datum was that > the calculated age differed by more than twice its error from that of > the plateau.(39) Lubenow clearly doesn't understand the age spectrum dating method. The quoted material has nothing to do with his paragraph above. The plateau is DEFINED as a plateau, that is, a set of points over which the graph is flat. By DEFINITION, points which show scatter are excluded from the plateau. This method is intended to overcome some problems with contamination etc. present in other methods. That the plateau EXISTS is evidence that a valid result is being obtained. This is the same method Fitch and Miller originally used. On the other hand, later in the article it is observed that one of the determinations has too much scatter to BE a plateau. Maybe that's what Lubenow is thinking of. But my understanding of the method stops right there. Those interested can check out the literature. The point, however is: Lubenow's implication that data that doesn't fit is being arbitrarily excluded is absolutely false. > However, he maintained that the differences these matters made were > small, and he expressed complete satisfaction in his date of 1.88 myr > for the KBS Tuff. He did not neglect to mention tat this date was in > excellent accord with the other recent dating studies of the KBS Tuff. > > McDougall then issued one of the most stinging rebukes of a fellow > scientist that I can remember seeing in the scientific literature. He > referred to Fitch et al. and their older date for the KBS Tuff when he > said: > > On the basis of the large scatter in the ages and the small > proportion of 40Ar in the gas extracted from the anorthoclase > concentrates, I suggest that the results are analytically less precise > than given by these authors. > > I suggest that unrecognized analytical difficulties and larger > than quoted errors must be invoked to explain these earlier 40Ar/39Ar > results.(40) > > McDougall was accusing Fitch et al. of invoking what is affectionately > known in scientific circles as 'the fudge factor' (deliberate > falsification of data to achieve a desired result). If Lubenow really thinks the quoted material above amounts to an accusation of falsification of data, he is imagining things. However, I doubt that Lubenow is that honest. > The study of the ten-year controversy in the dating of the KBS Tuff is > tremendously revealing. Whereas the public is led to believe that these > dating methods are highly objective and accurate, the scientific > literature itself reveals that they are highly subjective. There is no > question that rock samples are often manipulated to give the desired The only "manipulation" is the intelligent selection of rocks to date. > results. There is also no question that this manipulation is done in > the utmost sincerity and with the noblest motives. But it is > manipulation nonetheless. The 'bad' material must be removed to allow > the 'good' material to be dated. But there is no way of knowing for > sure which material is 'good' and which is 'bad.' > > The history of the dating of the KBS Tuff reveals that no matter how > careful a scientist is in selecting his rock samples and in performing > his laboratory work, if he gets the wrong date for his rocks he is open > to the charge of using contaminated material and a defective > methodology. The charges need not be proved. The fact that he got the > wrong date if proof enough. The literature suggests that even if This is based on inadequate evidence. The fact is, different researchers got different dates in this case. If Curtis et. al. had gotten 2.61 Mya in the first place, then Fitch et. al. would have been much less open to the charges described above. > radiometric dating were valid in concept (which it is not), the > practical matter of selecting rock samples that can be proven pure and > uncontaminated requires an omniscience that is beyond the ability of > mortal humans. The radioactive dating methods are a classic example of > selfdecption and circular reasoning. It is another of the myths of > human evolution. Naeser et al. have said it well: > > The accuracy of any age can only be guessed at, in that we do > not know the true age of any geologic sample. We can only strive for > the best agreement with K-Ar and the other dating methods.(41) Sorry. Analogy: my exact height can only be guessed at. I don't know my true height. I can only strive for the best agreement between measuring it with a yardstick and measuring it with a tape measure. > I have no doubt that my evolutionist friends will protest that I have > not been fair. "East Turkana," they will say, "is a most unique > situation. It just isn't 'cricket' to take a unique situation with its > many problems and imply that it is the norm." In this response, my > friends are both right and wrong. There is no question that the geology > of the Koobi Fora Formation, with the KBS Tuff, is exceedingly complex. > However, Koobi Fora is far from the only fossil site that has a very > complex geology. What is unique about Koobi Fora is something that so > far has not been mentioned by anyone. > > The radiometric date of 2.61 mya for the KBS Tuff was established before > skull 1470 was discovered. It was supported by faunal correlation, > paleomagnetism, and fission-track dating. Up until that time, the > fossils and the artifacts that had been found in association with the > KBS Tuff were more or less compatible with that older date. It is > entirely possible that if skull 1470 had never been found, the KBS Tuff > sould still be dated at 2.61 mya. We would continue to be told that it > was a 'secure date' based on the precision of radiometric dating and the > 'independent' confirmation of other dating techniques that acted as > controls. It was the shocking discovery of the morphologically modern > skull 1470, located well below the KBS Tuff, that precipitated the > ten-year controversy. > > What normally happens in a fossil discovery is that the fossils are > discovered first. Then attempts are made to date the rock strata in > which they are found. Under these conditions, a paleoanthropologist has > a degree of control over the rsults. He is free to reject dates that do > not fit the evolution scenario of the fossils. He is not even required > to publish those 'obviously anomalous' dates. The result is a very > sanguine and misleading picture of the conformity of the human fossil > record with the concept of human evolution. If, in many of these fossil > sites the dates had been determined before the fossils had been > discovered, evolutionists could not guarantee that the turbulent history > of the dating of the KBS Tuff would not have been repeated many times. > > The pigs won! In the ten-year controversy over the dating of one of the > most important human fossils ever discovered, the pigs won. The pigs > won over the elephants. The pigs won over K-Ar dating. The pigs won > over 40Ar-39Ar dating. The pigs won over fission-track dating. The won > over paleomagnetism. The pigs took it all. But in reality, it wasn't > the pigs that won. It was evolution that won. In the dating game, > evolution always wins.(42) Okay. I won't bother to argue that the KBS tuff is an exceptional case, since Lubenow has already anticipated my argument. However, I will say this: all this whining about circular argument is ludicrous, given the history of the various dating methods. Analogy: "Well, that's a car alarm I've never heard before." "How do you know it's a car alarm? Did you see the car?" Anyone who has followed the evolution of car alarms as long as I have knows that any further discussion, at this point, is useless. And, yes, I HAVE been ASSUMING that all those weirder and weirder noises were produced by cars; I don't generally go out there and track each one down to confirm the fact. And if you ask me what I mean by ASSUMING, well, further discussion IS useless. > Endnotes > > 1-5. F.J. Fitch and J.A. Miller, "Radioisotopic Age Determinations of > Lake Rudolf Artifact Sites," Nature 226 (18 April 1970):226-28. > > 6. Detroit Free Press, November 10, 1972. > > 7. R.E.F. Leakey, "Evidence for an Advanced Plio-Pleistocene Hominid > from East Rudolf, Kenya," Nature 242 (13 April 1973):447. > > 8. Vincent J. Maglio, "Vertebrate Faunas and Chronology of > Hominid-bearing Sediments East of Lake Rudolf, Kenya," Nature 239 (13 > October 1972):379-85. > > 9-13. A. Brock and G. L. Isaac, "Paleomagnetic stratigraphy and > chronology of hoinid-bearing sediments east of Lake Rudolf, Kenya," > Nature 247 (8 February 1974):344-48. > > 14. Anthony J. Hurford, "Fission track dating of a vitric tuff from East > Rudolf, North Kenya," Nature 249 (17 may 1974): 236. > > 15. F.J. Fitch, I.C. Findlater, R.T. Watkins, and J.A. Miller, "Dating > of a rock succession containing fossil hominids at East Rudolf, Kenya," > Nature 251 (20 September 1974): 214. > > 16. R.E. Leakey, "Skull 1470," National Geographic, June 1973: 819. > > 17-19. G.H. Curtis, Drake, T. Cerling and Hampel, "Age of KBS Tuff in > Koobi Fora Formation, East Rudolf, Kenya," Nature 258 (4 December 1975): > 395-98. > > 20-22. F.J. Fitch, P.J. Hooker, and J.A. Miller, "40Ar/39Ar dating of > the KBS Tuff in Koobi Fora Formation, East Rudolf, Kenya," Nature 263 > (28 October 1976): 740-42. > > 23-24, 27. A.J. Hurford, A.J.W. Gleadow, and C.W. Naeser, "Fission-track > dating of pumice from the KBS Tuff, East Rudolf, Kenya," Nature 263 (28 > October 1976):738-39. > > 25. G.A. Wagner, letter, Nature 267 (16 June 1977): 649. > > 26, 41. Naeser, Hurford, and Gleadow, letter, Nature 267 (16 June 1977): > 649. > > 28-29. J.W. Hillhouse, J.W.M Ndombi, A.Cox, and A. Brock, "Additional > results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east > of Lake Turkana (Lake Rudolf), Kenya," Nature 265 (3 February 1977):411-414. > > 30. D.C. Johanson and M.A. Edey, "Lucy: The Beginnings of Humankind" > (New york: Simon and Schuster, 1981), 240. Bracketed material added for clarity. > > 31, 33. H.B.S. Cooke, "Suid Evolution and Correlation of African Hominid > Localities, An Alternative Taxonomy," Science 201 (4 August 1978): > 460-63. > > 32. T.D. White and J.M. Harris, "Suid Evolution and Correlation of > African Homi nid Localities," Science 198 (7 October 1977): 13-21. > > 34-35. A.J.W. Gleadow, "Fission track age of the KBS Tuff and associated > hominid remains in northern Kenya," Nature 284 (20 March 1980): 229-230. > > 36-38. I McDougall, R. Maier, P. Sutherland-Hawkes, and A.J.W. Gleadow, > "K-Ar age estimate for the KBS Tuff, East Turkana, Kenya," Nature 284 > (20 March 1980): 230-32. > > 39-40. I McDougall, "40Ar/39Ar age spectra from the KBS Tuff, Koobi Fora > Formation," Nature 294 (12 November 1981): 123-24. > > 42. Chapter 9 and 10 of Roger Lewin's "Bones of Contention" contain his > account of the ten year history of dating the KBS Tuff. Since my > account was written independently of his, it would be an enlightening > experience to read his account also. By omitting many of the details > that I have included, he is able to make the affair a graphic victory > for the dating methods. Accounts like his explain why many people > continue to put almost unlimted faith in the dating methods. > > --End of Appendix--The Dating Game by Lubenow > > OK. Now's the time for comments. It seems to me the best thing to do > would be to show how in this case and others that the dating methods are > actually independent. Documentation, even technical would be interesting. The best thing to do, first, for documentation, is go check out Lubenow's references. For more, Dalrymple has books out which discuss all this. -- |---------------+--------------------------------------------------------------| Lee Davidson | Josh McDowell fans would do well to talk to my ex-girlfriend. lmd@netcom.com | Liar, lunatic, or absolutely reliable first-hand eyewitness std disclaimer | of the dawning of the New Age? Let them decide. |---------------+--------------------------------------------------------------| Article 136551 of talk.origins: Newsgroups: talk.origins Path: news.helsinki.fi!news.funet.fi!news.csc.fi!news.eunet.fi!EU.net!howland.reston.ans.net!ix.netcom.com!netcom.com!lmd From: lmd@netcom.com (Lee Davidson) Subject: Re: Independent Dating Methods: a Case Study Message-ID: Organization: NETCOM On-line Communication Services (408 261-4700 guest) X-Newsreader: TIN [version 1.2 PL1] References: <42fqk8$q5v@usenet.INS.CWRU.Edu> Date: Wed, 6 Sep 1995 18:15:27 GMT Lines: 189 Sender: lmd@netcom10.netcom.com Some extra points. I've kept only key sections and notes. Lee Davidson (lmd@netcom.com) wrote: : C. Allen Roy (hb426@cleveland.Freenet.Edu) wrote: : > The "small programme" at Berkeley is a reverence to the work of Curtis : > et al. who dated the KBS Tuff at 1.6 and 1.82 myr. The flaw in that : > date is quite obvious to Fitch, Hooker, and Miller: : > : > ...K-Ar apparent ages in the range 1.6-1.8 myr obtained from the : > KBS Tuff by other workers are regarded as discrepant, and may have been : > obtained from samples affected by argon loss.(22) : > : > This exercise can appropriately be named the dating game. Since yours : > is obviously the correct date, those who arrive at a younger date had : > samples that obviously had experienced argon loss. A date older than : > yours can be explained if you declare that those samples had obviously : > inherited excess argon from older rock. How does one refute that kind : > of logic? [That's logic?!] : Using isochron methods you can eliminate the possibility of argon : gain/loss. Curtis et. al. found good isochrons for their younger date. : Fitch and Miller found a good isochron for their "age spectrum : plateau" yielding the older date. I'm not sure what the explanation : is, but when you get an isochron this indicates you're dating : SOMETHING. So I'd say it's the detritus problem again. There is still a kind of mystery here, not cleared up, as far as I could see, in the references. If Fitch and Miller found isochrons, then this implies a correlation between their measurements which is hard to understand. Contamination of juvenile material with non-juvenile material ought to result in a scatter of ages older than the real age, not isochrons for a single older age, unless Fitch and Miller just happened to pick up stuff that was all formed at some earlier time. If they had gotten dates of 20 Mya consistently, or even 500 Mya, then we could argue for older stuff. But I didn't see any references in the literature to any eruption events producing stuff 2.44 Mya. : > [snip] : > One more item needs to be mentioned. Fitch, et al. commented that the : > Berkeley group reported 'scatter' in their dates ranging from 1.5 to 6.9 : > myr. Fitch et al. reported their own scatter in apparent ages ranging : > from .5 to 2.4 myr. In : > some cases the scatter was interpreted as overprinting events. In other : > cases, 'naughty' crystals were removed to give results more appropriate : > to the overriding principle behind it all -- human evolution. : This is a total distortion of the Fitch et. al. article. The closest thing : I could find to a reference to removing "naugthy crystals" is: : "Each of the samples was a cleaned and acid-washed feldspar crystal : concentrate extracted from pumice by hand picking only the most : obviously juvenile crystals from sawn slabs of pumice beneath a : binocular microscope." : If these crystals were naughty, Fitch et. al. knew they were beforehand. : A serious discrepancy, however, still remains, since the process of : hand-picking juvenile crystals led to different ages, depending on : the experimenter. : But even this is not as serious as you might think. If we suspect : that what we think are juvenile crystals might not be juvenile, then : we simply keep trying to pick out juvenile crystals again and again. : Eventually, if what we thought was juvenile was older detritus, we'll : run into some juvenile crystals, and age determination will yield : successively lesser values, approaching some limit, which is the time : of the eruption. And that limit has been reached -- 1.88 Mya. The mystery about the consistency of Fitch et. al.'s results remains. Note that this doesn't apply to the fission-track results. Gleadow's later fission-track dating yields 1.87 Mya. Hurford's earlier fission-track dating was done together with Gleadow, yielding 2.44 Mya. Gleadow thinks the consistency of the earlier results was due to systematic error, and notes that, in continued applications of the procedures, the consistency disappeared, to be replaced by scatter. Quoting from (34-35): "These [earlier] ages apparently agree closely with each other but this is mainly due to the close communication between these authors on track identification and discrimination in these samples. Further work has not supported this consistency but initially produced a much larger scatter of results. It has become clear that this scatter was due to analytical rather than geological factors and that some of the potential difficulties had not been given adequate consideration in the earlier results." He then goes on to propose a better experimental protocol, e.g., doing all track counting before computing ages so as not to introduce experimenter bias into the results. : > Endnotes : > : > 1-5. F.J. Fitch and J.A. Miller, "Radioisotopic Age Determinations of : > Lake Rudolf Artifact Sites," Nature 226 (18 April 1970):226-28. : > : > 6. Detroit Free Press, November 10, 1972. : > : > 7. R.E.F. Leakey, "Evidence for an Advanced Plio-Pleistocene Hominid : > from East Rudolf, Kenya," Nature 242 (13 April 1973):447. : > : > 8. Vincent J. Maglio, "Vertebrate Faunas and Chronology of : > Hominid-bearing Sediments East of Lake Rudolf, Kenya," Nature 239 (13 : > October 1972):379-85. : > : > 9-13. A. Brock and G. L. Isaac, "Paleomagnetic stratigraphy and : > chronology of hoinid-bearing sediments east of Lake Rudolf, Kenya," : > Nature 247 (8 February 1974):344-48. : > : > 14. Anthony J. Hurford, "Fission track dating of a vitric tuff from East : > Rudolf, North Kenya," Nature 249 (17 may 1974): 236. : > : > 15. F.J. Fitch, I.C. Findlater, R.T. Watkins, and J.A. Miller, "Dating : > of a rock succession containing fossil hominids at East Rudolf, Kenya," : > Nature 251 (20 September 1974): 214. : > : > 16. R.E. Leakey, "Skull 1470," National Geographic, June 1973: 819. : > : > 17-19. G.H. Curtis, Drake, T. Cerling and Hampel, "Age of KBS Tuff in : > Koobi Fora Formation, East Rudolf, Kenya," Nature 258 (4 December 1975): : > 395-98. : > : > 20-22. F.J. Fitch, P.J. Hooker, and J.A. Miller, "40Ar/39Ar dating of : > the KBS Tuff in Koobi Fora Formation, East Rudolf, Kenya," Nature 263 : > (28 October 1976): 740-42. : > : > 23-24, 27. A.J. Hurford, A.J.W. Gleadow, and C.W. Naeser, "Fission-track : > dating of pumice from the KBS Tuff, East Rudolf, Kenya," Nature 263 (28 : > October 1976):738-39. : > : > 25. G.A. Wagner, letter, Nature 267 (16 June 1977): 649. : > : > 26, 41. Naeser, Hurford, and Gleadow, letter, Nature 267 (16 June 1977): : > 649. : > : > 28-29. J.W. Hillhouse, J.W.M Ndombi, A.Cox, and A. Brock, "Additional : > results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east : > of Lake Turkana (Lake Rudolf), Kenya," Nature 265 (3 February 1977):411-414. : > : > 30. D.C. Johanson and M.A. Edey, "Lucy: The Beginnings of Humankind" : > (New york: Simon and Schuster, 1981), 240. Bracketed material added for clarity. : > : > 31, 33. H.B.S. Cooke, "Suid Evolution and Correlation of African Hominid : > Localities, An Alternative Taxonomy," Science 201 (4 August 1978): : > 460-63. : > : > 32. T.D. White and J.M. Harris, "Suid Evolution and Correlation of : > African Homi nid Localities," Science 198 (7 October 1977): 13-21. : > : > 34-35. A.J.W. Gleadow, "Fission track age of the KBS Tuff and associated : > hominid remains in northern Kenya," Nature 284 (20 March 1980): 229-230. : > : > 36-38. I McDougall, R. Maier, P. Sutherland-Hawkes, and A.J.W. Gleadow, : > "K-Ar age estimate for the KBS Tuff, East Turkana, Kenya," Nature 284 : > (20 March 1980): 230-32. : > : > 39-40. I McDougall, "40Ar/39Ar age spectra from the KBS Tuff, Koobi Fora : > Formation," Nature 294 (12 November 1981): 123-24. : > : > 42. Chapter 9 and 10 of Roger Lewin's "Bones of Contention" contain his : > account of the ten year history of dating the KBS Tuff. Since my : > account was written independently of his, it would be an enlightening : > experience to read his account also. By omitting many of the details : > that I have included, he is able to make the affair a graphic victory : > for the dating methods. Accounts like his explain why many people : > continue to put almost unlimted faith in the dating methods. : > : > --End of Appendix--The Dating Game by Lubenow : > : > OK. Now's the time for comments. It seems to me the best thing to do : > would be to show how in this case and others that the dating methods are : > actually independent. Documentation, even technical would be interesting. : The best thing to do, first, for documentation, is go check out Lubenow's : references. For more, Dalrymple has books out which discuss all this. : -- : |---------------+--------------------------------------------------------------| : Lee Davidson | Josh McDowell fans would do well to talk to my ex-girlfriend. : lmd@netcom.com | Liar, lunatic, or absolutely reliable first-hand eyewitness : std disclaimer | of the dawning of the New Age? Let them decide. : |---------------+--------------------------------------------------------------| -- |---------------+--------------------------------------------------------------| Lee Davidson | Josh McDowell fans would do well to talk to my ex-girlfriend. lmd@netcom.com | Liar, lunatic, or absolutely reliable first-hand eyewitness std disclaimer | of the dawning of the New Age? Let them decide. |---------------+--------------------------------------------------------------| Article 136567 of talk.origins: Path: news.helsinki.fi!news.funet.fi!news.csc.fi!news.eunet.fi!EU.net!news.sprintlink.net!in1.uu.net!cis.ohio-state.edu!magnus.acs.ohio-state.edu!csn!symbios.com!vangelis!jimf From: jimf@vangelis.FtCollins.NCR.com (Jim Foley) Newsgroups: talk.origins Subject: Re: Independent Dating Methods: a Case Study Date: 6 Sep 1995 19:30:28 GMT Organization: Symbios Logic, FT. Collins, CO. 80525 (303) 223-5100 Lines: 145 Message-ID: <42kssl$jvq@jupiter.WichitaKS.HMPD.COM> References: <42fqk8$q5v@usenet.ins.cwru.edu> NNTP-Posting-Host: vangelis.ncrmicro.ncr.com In article <42fqk8$q5v@usenet.ins.cwru.edu>, C. Allen Roy wrote: =>Below is an edited version of "The Dating Game", refer to the full text =>for more detail. => => THE DATING GAME (condensed) => =>The most important fossil discovered there is KNM-ER 1470. Skull 1470 =>is very modern in appearance but was originally believed to be about 2.9 =>million years old. This conflict between its modern appearance and its =>ancient age presented a serious challenge to all currently held theories =>of human evolution. Lubenow exaggerates the seriousness of this conflict. Evolution could fairly easily accommodate H. habilis at 2.9 million years, if that's what the evidence showed. It was a surprise in 1972 because there were no older australopithecines. Now there are. =>The first question an outside observer would ask is, How did they know?! =>The answer is that the fossils told them so. In spite of our being =>assured that the dating methods constitute an 'independent' confirmation =>of evolution, the fossils had already determined the outside limits for =>the dates that would be "acceptable." Based on their alleged evolution, =>the australopithecine and other mammalian fossils found beneath the KBS =>Tuff had pre-determined that the rocks should be somewhere between 2 and =>5 myo. Anything beyond that was "obviously" the result of "extraneous =>argon." True; and confirmed by the fact that when better and non-contaminated samples were chosen, the date was within that range. The impression I got was that this first date of 200+ million years was not expected to give a 'real' date. =>Dates of 212 to 230 MYA were notoriously far off. These dates would =>place the KBS Tuff in the Triassic period of the Mesozoic era, which is =>early dinosaur times. Everybody knows that Dinosaurs and Hominids were =>not contemporary, hence it is obvious that these dates were wrong. =>Without the fossils, however, there would be no way for a geologist to =>know if these were GOOD dates or BAD dates. Under other circumstances =>and no fossils, the geologists could well have accepted these dates as =>GOOD dates. When fitting rock layers into their "proper sequences" over =>large geographic areas, it is evolution and the fossils that guide the =>geologists -- not radiometric dating. Not evolution, but the geological column, is the guide for relative dating. The geological column is in turn explained by evolution, which has beaten out other contenders such as "hydrodynamic sorting". =>To compensate for this "obvious error" in dating the KBS Tuff, Fitch and =>Miller stated: "... it would only be possible to date this tuff by =>careful extraction of undoubtedly juvenile components for analysis."(4) =>In other words, Fitch and Miller then proceeded to remove from the =>whole-rock samples those components of the rock which they believed were =>"undoubtedly" juvenile or young, that showed no sign of weathering or =>alteration. The observer can be forgiven if he asks another question, =>How do they know for sure which components of the rock are undoubtedly =>young?! Before casting doubt on the competence of professional geologists, Lubenow should perhaps have made the effort to *find out* how they made this judgement? =>Leakey, however, continued to fight for the original date. Although he =>was committed to evolution and was aware of the problem the date for =>skull 1470 presented for evolution, his situation was somewhat =>different. He was considered the discoverer of skull 1470. No one will =>care if you discover the oldest fossil broccoli, but if you are =>fortunate enough to discover the oldest fossil human, the world will =>beat a path to your door. The acclaim and prestige such a person =>receives is beyond belief. Human fossils work a very special kind of =>magic. Leakey need this magic. He was only twenty-eight when skull =>1470 was discovered, and he had had no formal college training. He =>learned paleoanthropology at the feet of his parents, Louis and Mary =>Leakey. Some paleoanthropologists have never forgiven him for entering =>the field by a different door. The problems that 1470's age would pose =>for evolution were not as vital to him as the status 1470 would give him =>is establishing him in the field of paleoanthropology. Hence, he =>resisted any lowering of the date for 1470. I find it somewhat offensive to suggest, without any evidence, that selfish motives were behind his support of the older age. Why not assume that, like the rest of us, he might have gotten more emotionally attached to a particular opinion than was warranted. =>All of the above-cited articles spoke of the great difficulty in getting =>rock or crystal samples that were not altered, weathered, or derived =>from older rock. Curtis et al. explained at length their efforts to =>extract from the whole-rock samples the portions that were suitable for =>dating. However, Fitch and Miller also went to great lengths to extract =>suitable samples. The question arises, How does one know when one has =>good samples for dating? The only answer to that question is that =>"good" samples give dates that are in accord with evolutionary =>presuppositions. "Bad" samples are the ones that give dates not in =>conformity with evolution--a classic illustration of circular reasoning. With the difference that good dates should be repeatable, but bad dates won't be. Fitch and Miller never reproduced their initial 2.61 my date. =>The radiometric date of 2.61 mya for the KBS Tuff was established before =>skull 1470 was discovered. It was supported by faunal correlation, =>paleomagnetism, and fission-track dating. Up until that time, the =>fossils and the artifacts that had been found in association with the =>KBS Tuff were more or less compatible with that older date. It is =>entirely possible that if skull 1470 had never been found, the KBS Tuff =>sould still be dated at 2.61 mya. We would continue to be told that it =>was a 'secure date' based on the precision of radiometric dating and the =>'independent' confirmation of other dating techniques that acted as =>controls. It was the shocking discovery of the morphologically modern =>skull 1470, located well below the KBS Tuff, that precipitated the =>ten-year controversy. Even without 1470 a reevaluation of the date would probably have happened anyway. It happens all the time. 1470 merely sped things up because everyone was particularly anxious to know it's age. =>The pigs won! In the ten-year controversy over the dating of one of the =>most important human fossils ever discovered, the pigs won. The pigs =>won over the elephants. The pigs won over K-Ar dating. The pigs won =>over 40Ar-39Ar dating. The pigs won over fission-track dating. The won =>over paleomagnetism. The pigs took it all. But in reality, it wasn't =>the pigs that won. It was evolution that won. In the dating game, =>evolution always wins.(42) The pigs won because they formed identifiable, similar sequences in two different locations. Should we assume instead that they were hydrodynamically sorted so that they appeared in some order? Gripes aside, I actually think Lubenow did a fairly good job of showing how preconceptions can color interpretations. I'm not endorsing his recounting of the story until I can check it against other sources such as Roger Lewin's "Bones of Contention", but I think it's quite possible that some of the "independent" datings were colored by what people thought the results should be. -- Jim (Chris) Foley, jim.foley@symbios.com Assoc. Prof. of Omphalic Envy Research interest: Department of Anthropology Primitive hominids University of Ediacara (Australopithecus creationistii) Article 136644 of talk.origins: Newsgroups: talk.origins Path: news.helsinki.fi!news.funet.fi!news.csc.fi!news.eunet.fi!EU.net!howland.reston.ans.net!ix.netcom.com!netcom.com!lmd From: lmd@netcom.com (Lee Davidson) Subject: Re: Independent Dating Methods: a Case Study Message-ID: Organization: NETCOM On-line Communication Services (408 261-4700 guest) X-Newsreader: TIN [version 1.2 PL1] References: <42fqk8$q5v@usenet.INS.CWRU.Edu> Date: Thu, 7 Sep 1995 05:28:11 GMT Lines: 43 Sender: lmd@netcom17.netcom.com Final extra comments. I just read Lewin's Chapters 9 and 10 in _Bones of Contention_. (1) I fail to see how Lubenow could possibly think Lewin left very much out of Lewin's account of the matter. This includes references to anomalous 200 Mya dates, difficulties of determining juvenile material, experimenter bias. (2) Lewin brings out quite nicely how Hurford and Gleadow's initial bias towards the 2.4 Mya figure influenced their first fission track dating. They were computing dates all along the way, while they counted tracks. Gleadow was well aware that the knowledge of where the results were going, or should be going, was influencing decisions regarding things which looked like tracks but might not be tracks. His later fusion-track results we done according to a blind experimental protocol, dates not being computed until the end. (3) Fitch and Miller were getting quite a bit of scatter all along the way. (4) Fitch and Miller showed a strange reluctance to publish data, rather than conclusions. Darymple, who reviewed one of their submissions (and rejected it), complained that it was impossible for other scientists to check their data and computations. (5) Leakey was very strongly inclined towards an older Homo, both because he liked the idea and it would help him get funding. Which brings me to the final point: Lubenow's contention that the younger date was preferred because it "saved" human evolution would seem to prima facie miscorrelate very badly with the data -- in view of the fact that Leakey, a noted evolutionist whose career would certainly have been affected if evolution had come to be known to be false, opposed that younger date. And, as a matter of fact, there is nothing in Lewin's account to suggest that it wasn't the pigs, after all -- and not the humans -- who finally won the day. (With a crucial assist, however, I might point out, from radiometric dating.) -- |---------------+--------------------------------------------------------------| Lee Davidson | Josh McDowell fans would do well to talk to my ex-girlfriend. lmd@netcom.com | Liar, lunatic, or absolutely reliable first-hand eyewitness std disclaimer | of the dawning of the New Age? Let them decide. |---------------+--------------------------------------------------------------| Article 136611 of talk.origins: Path: news.helsinki.fi!news.funet.fi!news.eunet.fi!EU.net!howland.reston.ans.net!agate!kustu1.berkeley.edu!user From: timi@mendel.berkeley.edu (Tim Ikeda) Newsgroups: talk.origins Subject: Re: Independent Dating Methods: a Case Study Date: Wed, 06 Sep 1995 17:16:11 -0800 Organization: UC-Berkeley Plant biology Lines: 42 Message-ID: References: <42fqk8$q5v@usenet.INS.CWRU.Edu> NNTP-Posting-Host: kustu1.berkeley.edu C. Allen Roy (hb426@cleveland.Freenet.Edu) wrote: [From _Bones of Contention_...] >> McDougall et al. then stated how 'remarkably concordant' their own dates >> were at 1.9 myr after removing from consideration samples that gave ages >> of 4.11 and 7.46 myr. They explained these anomalous ages as follows: [Deletion...from McDougal quote...] >> Nevertheless, there is no doubt that old detrital material was >> being brought into the East Turkana Basin during deposition >> of the sediments.(38) >> >> With this clear victory of philosophy over observation, they then used >> the concordance of their results and agreement with the results of the >> study by Gleadow to give validity to their date for the KBS Tuff. In article , lmd@netcom.com (Lee Davidson) responds: : Okay. It's already known that there is a problem with contamination. : Then McDougall et. al. get ages of: 1.90, 1.89, 1.99, 1.97, 1.86, 1.87, : 1.88, 2.00, 1.90, 1.89, 1.89, 1.89, 1.87, 1.88, 1.90, 1.87, 1.88, 1.91, : 1.89, 1.88, 1.87, 1.90, 1.93, 1.89, 1.94, 1.87, 1.90, 1.86, 1.90, : 7.46, 4.11 Mya. (I'm quoting these values from the article.) : So, does it look like the elimination of two anomalous values (obtained, : by the way, from two independent measurements of the same sample) is : special pleading? Lubenow would never make it as a scientist. Let's see... McDougall's group got results from 29 samples that give a mean of 1.8990 MYa and a standard deviation of 0.0356 MYa (1.8% of the mean). Lubenow is whining about throwing out two outliers that fall 62 and 156 standard deviations away from the other 29 samples?!!!* If what has been presented by Allen and Lee are really the facts then I'd have to worry that Lubenow's presentation of the event borders on blatant distortion, although I wouldn't yet rule out ignorance as a contributing factor. - Tim Ikeda (timi@mendel.berkeley.edu) * Even if one included the two anomalous results in that set, they'd still fall about 2-5 standard deviations above the mean (ie. they would still be candidates for tossing). Article 136903 of talk.origins: Path: news.helsinki.fi!news.funet.fi!news.kolumbus.fi!news.sprintlink.net!in1.uu.net!news-1a.csn.net!csn!symbios.com!vangelis!jimf From: jimf@vangelis.FtCollins.NCR.com (Jim Foley) Newsgroups: talk.origins Subject: Re: A Case Study Date: 8 Sep 1995 20:52:41 GMT Organization: Symbios Logic, FT. Collins, CO. 80525 (303) 223-5100 Lines: 102 Message-ID: <42qaep$kkm@jupiter.WichitaKS.HMPD.COM> References: <42nuk2$j0o@usenet.ins.cwru.edu> NNTP-Posting-Host: vangelis.ncrmicro.ncr.com In article <42nuk2$j0o@usenet.ins.cwru.edu>, C. Allen Roy wrote: >In Chapter 15, entitled 'Homo habilis: The Little Man Who Isn't There', >Lubenow goes into more detail about skull 1470. If you read the book >you find that it is not Lubenow that calls skull 1470 'modern'. On page >162, Science News is quoted: 'Leakey further describes the whole shape >of the brain case as remarkably reminiscent of modern man, lacking the >heavy and protruding eyebrow ridges and thick bone characteristics of >Homo erectus.' (Science News 102 (18 November 1972):324) It was this >'modern' appearance that caused all the trouble in the first place. Aargh! He said "reminiscent" of modern man, not identical with it. It's "modern looking" *only compared to other hominid fossils of the same age*. No scientist has *ever* called 1470 Homo sapiens, and here's a number of reasons why it's not Homo sapiens: 1) Cronin et al.(1981) state: "KNM-ER 1470, like other early _Homo_ specimens, shows many morphological characteristics in common with gracile australopithecines that are not shared with later specimens of the genus _Homo_" 2) Wood (1991) states: "There is no evidence that this cranium particularly resembles _H. sapiens_ or _H. erectus_ according to either phenetic or cladistic evidence. Phenetically, KNM-ER 1470 is closest to the remains from Olduvai referred to _H. habilis_. In other words, 1470 is far more similar to many skulls that all creationists consider to be apes, than it is to modern humans, e.g. OH 16, OH 24, ER 1813. 3) Anecdotal evidence: when 1470 was being dug up, all they could see initially was the face, and they thought it belonged to a robust australopithecine. The face is *not* very human. 4) 1470's brain size is at the extreme, extreme low end of the human range. I'd be very suprised if 1 in 10,000 modern humans had such a small brain. But it's not just a pygmy or very small modern human: the teeth, as evidenced by the sockets, are huge. 5) Another difference: from the top, the skull looks less modern than it does from the front or side. The skull narrows markedly behind the eye sockets, so that you can see the zygomatic arches clearly from above, unlike in modern humans. 6) Another fragmented skull and associated teeth, 1590, is very similar in size to 1470. Everyone agrees it belongs to the same species as 1470. It belongs to a 6 yr old child (+/- 2 yrs), but the teeth are larger than those of Homo erectus, which are in turn larger than those of modern humans, even though the child's brain size is very small compared to modern children. 7) I think you would agree that not even a creationist, however incompetent, could mistake the skull of a modern human for that of an ape. But Duane Gish, the ICR expert on human evolution, thinks 1470 is an *ape*. Ergo, it does not belong to a modern human. So, those are some of the reasons for saying that 1470 is not Homo sapiens. Do you have any contrary evidence? Like a *single* scientist who says that it is Homo sapiens? I think point 8 above is particularly strong. If 1470 is not an ape human intermediate, *how come creationists can't even agree on what it is*? Interested to hear your thoughts on this. >I think that a reading of Lubenow's entire book would be very >challenging. Virtually the entire point of Lubenow's book rests on the fact that human species overlap in time. Lubenow considers this impossible, hence human evolution is disproved. This is an elementary misunderstanding of evolution. Once we accept that related species can live at the same time (and this is not even a minor difficulty for evolutionary theory), the major conclusions of Lubenow's book evaporate into smoke. If you agree with Lubenow here, you will have to show why it is impossible for, say, Homo erectus and Homo sapiens, to co-exist? The upcoming version of the hominid fossils FAQ will be addressing Lubenow's book in more detail. references: Cronin J.E., Boaz N.T., Stringer C.B. and Rak Y.: Tempo and mode in hominid evolution. Nature 292:113-122, 1981. Wood B.A.: Koobi Fora research project, volume 4: hominid cranial remains, Oxford:Clarendon Press, 1991. (a detailed study of fossils from the East Rudolf area) -- Jim (Chris) Foley, jim.foley@symbios.com Assoc. Prof. of Omphalic Envy Research interest: Department of Anthropology Primitive hominids University of Ediacara (Australopithecus creationistii)