Claim CD016:

Nobel prize nominee Melvin Cook discovered that lead-208 was found in ores in which it could not have come from decay of thorium-232 and could not have been "primordial" or "common" lead that was present when the ore solidified. The lead-208, therefore, must have been formed from lead-207 by neutron capture (Cook 1966). When neutron capture reactions are taken into account, the calculated age of the ores changes from approximately 600 million years to recent.

Source:

Response:

1. In one of his corrections for neutron capture, Cook (1966) calculated that an ore dated to 622 million years by conventional methods should be dated to 70 million years. This is still several orders of magnitude older than the Young-earth creationism time line. Creationists seldom (if ever) quote the reduced age derived by Cook; they call it "recent" (Ham et al. 1990) or "a few thousand years" (Slusher 1981, 54) or "essentially zero" (Morris 1985, 142).
   
   
2. The only evidence for neutron capture reactions on the necessary scale is Cook's analysis of a single secondary source. Cook made an unjustified assumption about the data he gathered from a secondary source (Dalrymple 1984). In table entries for lead-204 (Faul 1954), he read "----" as zero while the original source makes it clear that the dashes mean "not measured":

   In a number of samples where the abundance of ²⁰⁴Pb was very low no attempt was made to measure the amount of it as the determination would be of no particular value. (Nier 1939, 156)

   Cook deduced that the lead-208 could not be "common" lead (that is, lead present at solidification of the ore) because common lead always includes lead-204. The lead-208 is certainly not derived from decay of thorium-232, because there is no trace of thorium-232 left in the sample. However, since the amount of lead-208 in the samples is small and we have no reason to believe that lead-204 is not present, the lead-208 is almost certainly common lead.
   
   
3. Let us assume for the moment that the lead-208 is not common lead and was actually generated by neutron capture. Cook (1966) calculated his correction factor based on the (explicitly stated) assumption that the "cross-section" (a measurement of the probability of a nuclear reaction happening) for conversion of lead-206 to lead-207 by neutron capture is the same as the cross-section for conversion of lead-207 to lead-208 by neutron capture. This may have been a reasonable assumption in 1966, but it has not been a reasonable assumption since at least 1984. The two cross-sections differ by a factor of about 24 (e.g., Blackmon et al. 2002). When Cook's calculation is modified to account for the difference in cross-sections, the new calculated age is slightly older than the conventionally-calculated age; 644 million years versus 622 million years (Dalrymple 1984). If neutron capture is indeed a factor, our current best age for this ore is an underestimate.
   
   
4. Although it is not directly relevant to Cook's claims, it is worth noting that he was not nominated for a Nobel prize and did not (as is occasionally claimed) receive one. Melvin Cook (1911-2000) was an explosives expert who invented many important items (such as slurry explosives) and received a Nitro-Nobel medal for these contributions (Khodorovskiy n.d.) from the Nitro Nobel (now Dyno Nobel) company. He was also a prolific creationist who, among many other "contributions", originated the Not enough helium argument (Cook 1957) and first brought the Meister print to the attention of creationists (Cook 1970, 186-193).

References:

Further Reading:

Dalrymple, G. B. 1984. (see above)

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