========================================================================= Date: Mon, 20 Aug 2007 06:22:05 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: =?windows-1252?Q?Charles_O'Dale?= Subject: C14 in diamonds Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="windows-1252" Hi, first posting. I am researching how C14 gets into diamonds. So far I have reached the=20= conclusion that N14 is changed to C14 in the diamond by a radiation sourc= e=20 while it is deep in the earth.=20 Could someone elaborate on the process of making this carbon 14 isotope=20= within the diamond? Thank you Charles O'Dale President RASC - Ottawa Centre http://www.ottawa.rasc.ca/index.php http://www.ottawa.rasc.ca/science/index.html =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Mon, 20 Aug 2007 15:21:30 +0100 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Andrew Millard Subject: Re: C14 in diamonds In-Reply-To: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Has anyone actually reported C14 levels in diamonds? Google shows lots of hits for creationist reports, but I cannot find a single report in the scientific literature, or even a precise level or lab reported in the creationist literature. Andrew On Mon, 20 Aug 2007, [windows-1252] Charles O'Dale wrote: > I am researching how C14 gets into diamonds. So far I have reached the > conclusion that N14 is changed to C14 in the diamond by a radiation source > while it is deep in the earth. > > Could someone elaborate on the process of making this carbon 14 isotope > within the diamond? -- Dr. Andrew Millard A.R.Millard@durham.ac.uk Department of Archaeology, Tel: +44 191 334 1147 Durham University, South Road, Fax: +44 191 334 1101 Durham. DH1 3LE. U.K. http://www.dur.ac.uk/a.r.millard/ Department webpage: http://www.dur.ac.uk/archaeology/ MSc in Human Palaeoecology: http://www.dur.ac.uk/archaeology/postgraduate/msc_palaeoecology/ =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Mon, 20 Aug 2007 15:58:41 +0100 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Stewart Freeman Subject: Re: C14 in diamonds In-Reply-To: Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit In the proceedings of the last AMS conference Taylor and Southon describe direct measurement of natural diamond (NIM B259 2007 p282-7). We have also run splits of their diamonds and achieve age-equivalents of 80 kyrs (which incidentally is our result for geological graphite too). on 20/8/07 15:21, Andrew Millard at a.r.millard@DURHAM.AC.UK wrote: > Has anyone actually reported C14 levels in diamonds? Google shows lots of > hits for creationist reports, but I cannot find a single report in the > scientific literature, or even a precise level or lab reported in the > creationist literature. > > Andrew > > On Mon, 20 Aug 2007, [windows-1252] Charles O'Dale wrote: > >> I am researching how C14 gets into diamonds. So far I have reached the >> conclusion that N14 is changed to C14 in the diamond by a radiation source >> while it is deep in the earth. >> >> Could someone elaborate on the process of making this carbon 14 isotope >> within the diamond? -- Professor Stewart P.H.T. Freeman AMS Laboratory Scottish Universities Environmental Research Centre Scottish Enterprise Technology Park East Kilbride G75 0QF email: s.freeman@suerc.gla.ac.uk phone: +44 (0)1355 270187 fax: +44 (0)1355 229898 =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Mon, 20 Aug 2007 13:19:06 -0400 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Charles O'Dale Subject: Re: C14 in diamonds In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit The only paper I could find on the subject was regarding N14 in diamonds. Nitrogen isotopes in mantle-derived diamonds: indications of a multi-component structure Ratan K. Mohapatra1,2 and S. V. S. Murty1,* 1Planetary and Geosciences Division, Physical Research Laboratory, Ahmedabad 380 009, India 2Department of Earth Sciences, University of Manchester, Manchester, M13 9PL, UK And I have not seen any empirical evidence that there is C14 in diamonds. Charees O'Dale --- Andrew Millard wrote: > Has anyone actually reported C14 levels in diamonds? Google shows lots of > hits for creationist reports, but I cannot find a single report in the > scientific literature, or even a precise level or lab reported in the > creationist literature. > > Andrew > > On Mon, 20 Aug 2007, [windows-1252] Charles O'Dale wrote: > > > I am researching how C14 gets into diamonds. So far I have reached the > > conclusion that N14 is changed to C14 in the diamond by a radiation source > > while it is deep in the earth. > > > > Could someone elaborate on the process of making this carbon 14 isotope > > within the diamond? > -- > Dr. Andrew Millard A.R.Millard@durham.ac.uk > Department of Archaeology, Tel: +44 191 334 1147 > Durham University, South Road, Fax: +44 191 334 1101 > Durham. DH1 3LE. U.K. http://www.dur.ac.uk/a.r.millard/ > Department webpage: http://www.dur.ac.uk/archaeology/ > MSc in Human Palaeoecology: > http://www.dur.ac.uk/archaeology/postgraduate/msc_palaeoecology/ > Charles O'Dale President RASC - Ottawa Centre http://www.ottawa.rasc.ca/index.php http://www.ottawa.rasc.ca/science/index.html =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Mon, 20 Aug 2007 20:37:23 +0100 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Andrew Millard Subject: Re: C14 in diamonds In-Reply-To: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Thanks, Stewart, for the reference. It shows that the answer to Charles' question is: there isn't any detectable C14 in diamonds. Although apparent C14 ages of 68-80k BP were obtained, Taylor and Southon said "Previous tests showed that 14C count rates from silver powder cathodes were comparable with those from diamonds." This confirms that the C14 'detected' was an artefact of the machine, as is assumed by Taylor and Southon for the basis of their study. Andrew On Mon, 20 Aug 2007, Stewart Freeman wrote: > In the proceedings of the last AMS conference Taylor and Southon describe > direct measurement of natural diamond (NIM B259 2007 p282-7). We have also > run splits of their diamonds and achieve age-equivalents of 80 kyrs (which > incidentally is our result for geological graphite too). > > on 20/8/07 15:21, Andrew Millard at a.r.millard@DURHAM.AC.UK wrote: > > > Has anyone actually reported C14 levels in diamonds? Google shows lots of > > hits for creationist reports, but I cannot find a single report in the > > scientific literature, or even a precise level or lab reported in the > > creationist literature. > > > > On Mon, 20 Aug 2007, [windows-1252] Charles O'Dale wrote: > > > >> I am researching how C14 gets into diamonds. So far I have reached the > >> conclusion that N14 is changed to C14 in the diamond by a radiation source > >> while it is deep in the earth. > >> > >> Could someone elaborate on the process of making this carbon 14 isotope > >> within the diamond? -- Dr. Andrew Millard A.R.Millard@durham.ac.uk Department of Archaeology, Tel: +44 191 334 1147 Durham University, South Road, Fax: +44 191 334 1101 Durham. DH1 3LE. U.K. http://www.dur.ac.uk/a.r.millard/ Department webpage: http://www.dur.ac.uk/archaeology/ MSc in Human Palaeoecology: http://www.dur.ac.uk/archaeology/postgraduate/msc_palaeoecology/ =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Mon, 20 Aug 2007 13:02:44 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: blaauwm@CIMAT.MX Subject: Re: C14 in diamonds In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit A diamond with a measured C14 age of 80 kyr (c. 14 half lives) contains only some .006% of modern C14 levels. So, probably any C14 atoms counted in the diamonds merely show the background from the AMS measurements (e.g., accidentally add a tiny fragment of dandruff to your diamond and you get finite C14 ages)? > In the proceedings of the last AMS conference Taylor and Southon describe > direct measurement of natural diamond (NIM B259 2007 p282-7). We have also > run splits of their diamonds and achieve age-equivalents of 80 kyrs (which > incidentally is our result for geological graphite too). > > on 20/8/07 15:21, Andrew Millard at a.r.millard@DURHAM.AC.UK wrote: > >> Has anyone actually reported C14 levels in diamonds? Google shows lots >> of >> hits for creationist reports, but I cannot find a single report in the >> scientific literature, or even a precise level or lab reported in the >> creationist literature. >> >> Andrew >> >> On Mon, 20 Aug 2007, [windows-1252] Charles O'Dale wrote: >> >>> I am researching how C14 gets into diamonds. So far I have reached the >>> conclusion that N14 is changed to C14 in the diamond by a radiation >>> source >>> while it is deep in the earth. >>> >>> Could someone elaborate on the process of making this carbon 14 isotope >>> within the diamond? > > -- > Professor Stewart P.H.T. Freeman > > AMS Laboratory > Scottish Universities Environmental Research Centre > Scottish Enterprise Technology Park > East Kilbride G75 0QF > > email: s.freeman@suerc.gla.ac.uk > phone: +44 (0)1355 270187 > fax: +44 (0)1355 229898 > > ============================================================================ > To unsubscribe from this list, send the command SIGNOFF C14-L to > LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to > C14-L-request@LISTSERV.ARIZONA.EDU. > =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Mon, 20 Aug 2007 15:46:48 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "Heaton, Timothy H. (USD)" Subject: Re: C14 in diamonds In-Reply-To: <52757.148.235.65.243.1187632964.squirrel@correo.cimat.mx> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C7E36B.3ADA835C" This is a multi-part message in MIME format. ------_=_NextPart_001_01C7E36B.3ADA835C Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Below is a portion of a manuscript I wrote on the creationist radiocarbon argument. I am not an expert on this subject, but I have read Baumgardner's writings and corresponded with him on the subject. He insists that the radiocarbon levels in diamonds and old coal samples are well above machine error levels and that the labs he's worked with readily admit this. In his article (which I quote from below) he considers various proposals for the source of the radiocarbon, but of course he settles on a young-earth creation explanation. -Tim Professor Timothy H. Heaton /|Mountains /| Phone: 605-677-6122 Chair of Earth Science/Physics /::|Deserts /::| FAX: 605-677-6121 University of South Dakota /::::|Caves /::::| EM: theaton@usd.edu Vermillion, SD 57069 /::::::| /::::::| www.usd.edu/~theaton =20 While much of the experiment and analysis conducted by the RATE group is legitimate science, their conclusions are founded purely on religious biases and speculative miracles. The same transition from science to religion can be seen in their analysis of another poorly-understood phenomenon: A remarkable discovery made over the past twenty-five years is that organic samples from every level in the Phanerozoic portion of the geologic record, when tested by highly sensitive accelerator mass spectrometer (AMS) methods, display significant and reproducible amounts of 14C [carbon-14]. Because the lifetime of 14C is so brief, these AMS measurements pose an obvious challenge to the standard geological timescale that assigns millions to hundreds of millions of years to this part of the rock record.... Another noteworthy observation is that the 14C/C ratio of these samples appears to be uncorrelated with their position in the geological record.... A straightforward but startling inference from these AMS data is that all but the very youngest fossil material in the geologic record was buried contemporaneously only thousands of years ago in what must have been a major global cataclysm. The simultaneous destruction of so much life implies, however, that dramatically more total carbon (now in the form of coal, oil, and oil shale) had to be present in the earth's biosphere prior to this cataclysmic event.... Using a lower, more realistic estimate for the biospheric 14C/C ratio prior to the cataclysm reduces the actual 14C age by roughly a factor of ten from about 50,000 years to a value of about 5000 years. This latter estimate, of course, is consistent with the Biblical account of a global Flood that destroyed most of the life on the planet, both plants and animals, in a single brief cataclysm some four to five millennia ago. Finally, our 14C RATE project has measured 14C/C ratios above the AMS threshold in diamonds from a variety of locations [and] these measurements appear to limit the age of the physical earth itself to the range of thousands (as opposed to billions) of years. (Baumgardner 2005:587-588) Ironically, this conclusion would be stronger in the absence of accelerated decay since acceleration leads to the same expectation as an old earth, namely the decay of all short-lived radioisotopes. The lack of correlation between 14C values and the geologic column also contradicts values from other radioisotopes, which the RATE team accepted (in their compressed timescale) as mostly reliable dates. Furthermore, the presence of 14C traces in diamonds calls into question the biological origin of these low levels of 14C, which is a key assumption of the 5,000 year age estimate mentioned above. John Baumgardner found a convenient solution to all of these problems, however. He explored the possibility that 14C formed when 13C (a more common, stable isotope) captured a stray neutron, but he calculated that this phenomenon would produce 14C at only 1/13,000th the measured level (in diamonds) under prevailing conditions in the earth's crust. "On the other hand, a recent episode of accelerated nuclear decay corresponding to, say, 500 million years worth of U decay, would generate...0.5 pMC, which is close to what we measured in our diamond samples" (Baumgardner 2005:616). This explanation, by itself, nullifies useful creationist conclusions. So Baumgardner (2005:621) proposed that "only about 2000 years worth of accelerated 14C decay occurred during the Flood" (as opposed to 500,000,000 years of U decay) which "is well within the uncertainties in the 14C/C ratio we considered in connection with the pre-Flood world, so it has little impact on the larger issues discussed in this chapter" (i.e. simultaneous death of most life about 5,000 years ago). So while Baumgardner began with a genuine scientific puzzle that has perplexed researchers, in the end he assigned arbitrary values to a speculative phenomenon (accelerated decay) to support a preconceived religious conclusion. Baumgardner, John R. 2005. 14C evidence for a recent global flood and a young earth. Chapter 8 (pp. 587-630) in L. Vardiman, A. A. Snelling, and E. F. Chaffin (eds.) Radioisotopes and the Age of the Earth, Volume II: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, El Cajon, California, 818 p. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ------_=_NextPart_001_01C7E36B.3ADA835C Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable RE: C14 in diamonds

Below is a = portion of a manuscript I wrote on the creationist radiocarbon argument. = I am not an expert on this subject, but I have read = Baumgardner's writings and corresponded with him on the subject. He = insists that the radiocarbon levels in diamonds and old coal samples are = well above machine error levels and that the labs he's worked with = readily admit = this. In his article (which I quote from below) he considers various proposals = for the source of the radiocarbon, but of course he = settles on a = young-earth creation explanation. -Tim

Professor Timothy H. = Heaton        /|Mountains = /|     Phone:  605-677-6122

Chair of Earth = Science/Physics   /::|Deserts /::|     = FAX:    605-677-6121

University of South = Dakota     /::::|Caves = /::::|     EM:  = theaton@usd.edu

Vermillion, SD = 57069         = /::::::|    = /::::::|     = www.usd.edu/~theaton

While much of = the experiment and analysis conducted by the RATE group is legitimate = science, their conclusions are founded purely on religious biases and = speculative miracles. The same transition from science to religion can = be seen in their analysis of another poorly-understood = phenomenon:

      A remarkable = discovery made over the past twenty-five years is that organic samples = from every level in the Phanerozoic portion of the geologic record, when = tested by highly sensitive accelerator mass spectrometer (AMS) methods, = display significant and reproducible amounts of 14C [carbon-14]. Because the = lifetime of 14C is so brief, these AMS measurements pose an obvious = challenge to the standard geological timescale that assigns millions to = hundreds of millions of years to this part of the rock record…. = Another noteworthy observation is that the 14C/C ratio of these samples appears = to be uncorrelated with their position in the geological record…. = A straightforward but startling inference from these AMS data is that = all but the very youngest fossil material in the geologic record was = buried contemporaneously only thousands of years ago in what must have = been a major global cataclysm. The simultaneous destruction of so much = life implies, however, that dramatically more total carbon (now in the = form of coal, oil, and oil shale) had to be present in the earth’s = biosphere prior to this cataclysmic event…. Using a lower, more = realistic estimate for the biospheric 14C/C ratio prior to the cataclysm = reduces the actual 14C age by roughly a factor of ten from about 50,000 = years to a value of about 5000 years. This latter estimate, of course, = is consistent with the Biblical account of a global Flood that destroyed = most of the life on the planet, both plants and animals, in a single = brief cataclysm some four to five millennia ago. Finally, = our 14C RATE project has measured 14C/C ratios above the AMS threshold = in diamonds from a variety of locations [and] these measurements appear = to limit the age of the physical earth itself to the range of thousands = (as opposed to billions) of years. (Baumgardner = 2005:587-588)

Ironically, = this conclusion would be stronger in the absence of accelerated decay since = acceleration leads to the same expectation as an old earth, namely the = decay of all short-lived radioisotopes. The lack of correlation = between 14C values and the geologic column also contradicts = values from other radioisotopes, which the RATE team accepted (in their = compressed timescale) as mostly reliable dates. Furthermore, the = presence of 14C traces in diamonds calls into question the biological = origin of these low levels of = 14C, which is a key assumption of the 5,000 year age = estimate mentioned above. John Baumgardner found a convenient solution = to all of these problems, however. He explored the possibility = that 14C formed when = 13C (a more common, stable isotope) captured a stray = neutron, but he calculated that this phenomenon would = produce 14C at only 1/13,000th the measured level (in diamonds) = under prevailing conditions in the earth’s crust. “On the = other hand, a recent episode of accelerated nuclear decay corresponding = to, say, 500 million years worth of U decay, would generate…0.5 = pMC, which is close to what we measured in our diamond samples” = (Baumgardner 2005:616). This explanation, by itself, nullifies useful = creationist conclusions. So Baumgardner (2005:621) proposed that = “only about 2000 years worth of accelerated 14C decay occurred during the = Flood” (as opposed to 500,000,000 years of U decay) which = “is well within the uncertainties in the 14C/C ratio we considered in = connection with the pre-Flood world, so it has little impact on the = larger issues discussed in this chapter” (i.e. simultaneous death = of most life about 5,000 years ago). So while Baumgardner began with a = genuine scientific puzzle that has perplexed researchers, in the end he = assigned arbitrary values to a speculative phenomenon (accelerated = decay) to support a preconceived religious conclusion.

Baumgardner, = John R. 2005. 14C evidence for a recent global flood and a young earth. = Chapter 8 (pp. 587-630) in L. Vardiman, A. A. Snelling, and E. F. = Chaffin (eds.) Radioisotopes and the Age of the Earth, Volume II: = Results of a Young-Earth Creationist Research = Initiative, Institute for Creation Research, El Cajon, = California, 818 p.

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ------_=_NextPart_001_01C7E36B.3ADA835C-- ========================================================================= Date: Tue, 21 Aug 2007 09:33:04 -0400 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Charles O'Dale Subject: Re: C14 in diamonds In-Reply-To: <0D885F444196974595739923B2A1150201742CE7@usd-ex01.usd.local> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Thank you all who took the time to respond to my question of how C14 gets into diamonds. My amateur research up to this point was concentrated on the hypothesis that N14 contamination in diamonds was transformed into C14 by the natural radiation from the deep earth (similar to cosmic rays transforming N14 in the atmosphere to C14). Am I "out to lunch" on this one? Your responses seem to point to the fact that there has not been any documented C14 measured in diamonds. What was detected and published by the creationists was just contamination. The whole issue may be just a creationist "strawman" argument. As you have probably inferred by my question, there is a creationist in our RASC centre and I am seeking evidence to counter his rantings. Sincerely Charles O'Dale Charles O'Dale President RASC - Ottawa Centre http://www.ottawa.rasc.ca/index.php http://www.ottawa.rasc.ca/science/index.html =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU. ========================================================================= Date: Tue, 21 Aug 2007 07:53:33 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Timothy Jull Subject: Re: C14 in diamonds Comments: To: Charles O'Dale In-Reply-To: <849632.37397.qm@web88010.mail.re2.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Disposition: inline Content-Transfer-Encoding: 7bit Dear Charles, Please see Jull et al. (1987) On the 14C content of radioactive ores, Chemical Geology, 66, 35-40, which deals with the production of 14C by natural nuclear reactions. 14C can be produced by the reaction 14N(n,p) 14C in natural samples which have a significant neutron flux (and N). However, for samples of dating interest, this level is equivalent to >70,000 yr or so. We reported on some studies of high-U ores. It seems some replies were sidelined by a discussion of Baumgartner et al. I hope this is useful. regards, Tim A. J. Timothy Jull Professor, Geosciences NSF Arizona AMS Laboratory Physics Building, Univ of Arizona 1118 East Fourth St Tucson, AZ 85721 Tel. (520) 621-6816, Fax. (520) 621-9619 =========================================================================== To unsubscribe from this list, send the command SIGNOFF C14-L to LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to C14-L-request@LISTSERV.ARIZONA.EDU.