========================================================================= Date: Sun, 1 Jul 2001 11:56:32 +0200 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Nick van der Merwe Organization: University of Cape Town Subject: Re: AW: bone remodelling In-Reply-To: Dear Ian et al: Seven years after the bomb spike, in 1971,Glasgow Laboratory measured the C14 in human tissues (both skeletal and soft tissue)of a series of people of different ages who died that year. Ref:MJ Stenhouse and MS Baxter. Radiocarbon 18:161-171 (1976). John Vogel (retired director of the lab you are now working in) and I measured C14 in the femora of 4 people who died in the northern hemisphere in 1984: a male and female who died at age 60 and a male and female who died at 80.The collagen in the two male skeletons had not turned over AT ALL in the 20 years since the bomb spike; both the females had turned over 20% of their collagen. These data are not published, but you should find them in the records of your lab; the measurements were done around 1986 or 87. It is unfortunately a fact that the turnover rates of different parts of the skeleton at different ages are poorly known. The mineral phase is much better known than the protein(due to interest in osteoporosis, bone density meaurements,etc), and it turns over faster.All statements about the turnover rate of collagen(7 years, 10 years, those are the favourites) should be taken with a grain of salt. Regards, Nick van der Merwe Nikolaas J van der Merwe Professor of Natural History Archaeology Dept, U of Cape Town 7700 Rondebosch South Africa Ph. +27 21 650 4386 Fax +27 21 650 2352 Internet: Nikolaas@beattie.uct.ac.za =========================================================================== 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: Wed, 4 Jul 2001 14:54:46 +0200 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Karim Gernigon Subject: correction of an ancient date Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; format=flowed Content-Transfer-Encoding: 8bit Dear all, I'm working on a Neolithic site from southern France, called la Perte du Cros. This site was already excavated during the 50's by Antoine Galan and this archaeologist had, at this time, sent charcoal for radiocarbon analysis. These analysis were performed in 1959 by the laboratory of Gif-sur-Yvette in France and in 1961 by the Heidelberg lab in Germany. Antoine Galan has recently shown me the letters from the laboratories indicating the results of the analysis. The dates from Gif (GSY 35A and GSY 35B) are 4291 -124 +126 and 4127 -124 +126 (BP of course) (the specific radioactivity is reported: 3.63). Those results differ from what is generally published in France (especially in the database from the Lyon radiocarbon lab: http://carbon14.univ-lyon1.fr/banadora.html) which indicate 4210 +-150 for GSY 35A and 4800 +-130 for GSY 35B. I'd like to know if the difference is due to an error of transcription or to something else. I know that the radiocarbon half-life initially calculated by Libby was wrong and was after (but when?) recalculated (Cambridge half-life). Does it explain the difference between the results published? If this is the explanation, how should I do in order to recalculate the Heidelberg dates (performed in 1961)? And finally, from when is the Cambridge half-life utilized by the labs? (I'd like to know up to when I must recalculate the dates given by the labs). I hope my questions are understandable and many thanks in advance. Karim Karim GERNIGON UMR 5608 UTAH Préhistoire Maison de la Recherche Université Toulouse-le Mirail 31058 Toulouse Cedex France gernigon@univ-tlse2.fr http://www.quercy.net/institutions/prehistoire_quercinoise/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, 2 Jul 2001 12:46:09 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "Eric C. Grimm" Subject: Re: Dating bulk lake sediments In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Phil, Just got back from the field saw your message below. We have paired dates from a number of sites in the U.S. Midwest and Northern Great Plains. Some observations: 1. You don't have to have carbonate in the sediment for a reservoir effect. In some lakes the carbonate precipitates in carbonate benches in shallow water but not in the hypolimnion below the thermocline where the core came from, although the algae that ended up in the gyttja were happily incorporating old carbon from the epilimnion. In other lakes pre-Quaternary organic matter from coal, lignite, and carbon-containing shale is the primary contaminant. We have sites with reservoirs up to 8000 years. 2. The reservoir effect and sedimentation rates vary greatly through time. The only way to get a good estimate is with large number of AMS dates on terrestrial macros. I think we're kidding ourselves with statistically-derived age-depth models utilizing a small number of dates. 3. I have a number of sites that with the first 4 or 5 dates it appeared that one date must be an outlier, i.e. off the linear trend. Then with additional dates, the outlier was, in fact, accurate and other dates confirmed a significant change in sedimentation rate. Cheers, Eric Grimm At 12:21 AM 6/20/01 +0100, you wrote: >Dear all, > >I've been musing over this for a while and thought it might be a good area >for discussion... > >Recently I've noticed 14C dates on bulk organic-rich lake sediment >sometimes being adjusted for a reservoir effect, even in apparently low >carbonate sediments. In one case this adjustment was largely justified by >the fact that a linear age depth model (derived apparently from a >regression of the mean dates) suggested the surface sediment was several >hundred years old. > >My first reaction was to think 'why have they done that?' as it seems >packed full of assumptions, not least that accumulation was constant and >also that the reservoir effect was also constant over several millennia. >My second reaction was 'am I missing something important here?' - hence a >few questions which will hopefully draw out some state of the art >responses: > >1. In the absence of 14C dates on good terrestrial macrofossils or varves, >is there any way of assessing accurately and precisely whether a reservoir >adjustment is valid/needed? Can different extracts (solids, humics etc) be >used? > >2. Is there any evidence for variations in lake 14C reservoirs over time >and, if so, how quickly can the reservoir effect change and what controls >it? > >3. How reliable are statistically-derived age-depth models? How many >times do they match up with independent dating accurately and precisely? >I'm particularly interested from the point of testing hypotheses of >quasi-periodic environmental (climatic) cycles and identifying abrupt >change. > >I've got my own views on some of these, but I've spent most of my time >working in dodgy fluvial and coastal contexts where it pays to be sceptical >about dating, so I'm particularly interested to hear views from the lakes >community. > >Look forward to some discussion, > >Phil > >----------------------------------------- >Dr. Philip E.F. Collins Environmental Change Research Group >Department of Geography & Earth Sciences >Brunel University >Uxbridge UB8 3PH >United Kingdom > >Tel: +44 (0) 1895 274000 (Switchboard) ext 2381 >Fax: +44 (0) 1895 203217 >Email: philip.collins@brunel.ac.uk >http://www.brunel.ac.uk/depts/geo/people/philcollins.html > >Please consult our website: >http://www.brunel.ac.uk/depts/geo/Catastrophes/ >for the conference on "Holocene environmental catastrophes and >recovery", 2-7 Sept. 2002. > >============================================================================ >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. Dr. Eric C. Grimm Curator and Head of Botany Illinois State Museum Research and Collections Center 1011 East Ash Street Springfield, IL 62703 USA Office: 217-785-4846 Database: 217-524-0493 Fax: 217-785-2857 E-mail: grimm@museum.state.il.us Lat-Long: 39.46.48 N, 89.38.34 W =========================================================================== 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, 9 Jul 2001 09:24:23 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Emmanuelle Delque Subject: Re: correction of an ancient date In-Reply-To: <4.2.0.58.20010704142831.00958b90@mail.univ-tlse2.fr> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Dear Karim, The results GSY 35A and GSY 35B from Gif sur Yvette given in our database are taken from the datelist publised by Gif in Radiocarbon, vol 8, 1966. The author mentions that the results are calculated with 5570 years half-life. The description of the sample is : burnt wheat from Hearth III at the entrance of cave of Perte du Cros. The best is perhaps to call them to know if they have kept copy of their old files. Regards At 14:54 04/07/2001 +0200, Karim Gernigon wrote: >Dear all, > >I'm working on a Neolithic site from southern France, called la Perte du >Cros. This site was already excavated during the 50's by Antoine Galan and >this archaeologist had, at this time, sent charcoal for radiocarbon >analysis. These analysis were performed in 1959 by the laboratory of >Gif-sur-Yvette in France and in 1961 by the Heidelberg lab in Germany. >Antoine Galan has recently shown me the letters from the laboratories >indicating the results of the analysis. The dates from Gif (GSY 35A and >GSY 35B) are 4291 -124 +126 and 4127 -124 +126 (BP of course) (the specific >radioactivity is reported: 3.63). Those results differ from what is >generally published in France (especially in the database from the Lyon >radiocarbon lab: http://carbon14.univ-lyon1.fr/banadora.html) which >indicate 4210 +-150 for GSY 35A and 4800 +-130 for GSY 35B. >I'd like to know if the difference is due to an error of transcription or >to something else. I know that the radiocarbon half-life initially >calculated by Libby was wrong and was after (but when?) recalculated >(Cambridge half-life). Does it explain the difference between the results >published? If this is the explanation, how should I do in order to >recalculate the Heidelberg dates (performed in 1961)? >And finally, from when is the Cambridge half-life utilized by the labs? >(I'd like to know up to when I must recalculate the dates given by the labs). > >I hope my questions are understandable and many thanks in advance. > >Karim >Karim GERNIGON >UMR 5608 >UTAH Préhistoire >Maison de la Recherche >Université Toulouse-le Mirail >31058 Toulouse Cedex >France >gernigon@univ-tlse2.fr >http://www.quercy.net/institutions/prehistoire_quercinoise/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. > > > Emmanuelle Delqué-Kolic Centre de Datation par le Radiocarbone Université Claude Bernard Lyon 1 40, Bd Niels Bohr 69622 VILLEURBANNE Cedex tél. 04 72 43 13 18 fax. 04 72 43 13 17 delque@cismsun.univ-lyon1.fr =========================================================================== 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: Wed, 25 Jul 2001 15:08:16 +0200 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Iain Robertson Subject: silver 'wire' Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=_663C0EAF.D4B5D3F9" This is a MIME message. If you are reading this text, you may want to consider changing to a mail reader or gateway that understands how to properly handle MIME multipart messages. --=_663C0EAF.D4B5D3F9 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Dear colleagues, It's that once a decade time to order some silver 'wire' for the radiocarbo= n combustion line. Can anybody recommend a supplier?=20 The last sample (0.3mm wide; 0.013 mm thick) was ordered in 1990 from a = ISOTECH in the Netherlands. THANKS. Iain ********************************************* Dr Iain Robertson Quaternary Dating Research Unit,=20 CSIR Environmentek, PO Box 395,=20 0001 Pretoria, SOUTH AFRICA. Tel + 27 12 841 2300 Fax + 27 12 349 1170 ********************************************* --=_663C0EAF.D4B5D3F9 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Description: HTML
Dear colleagues,
It's that once a decade time to order some silver 'wire' for the=20 radiocarbon combustion line. Can anybody recommend a supplier? 
 
The last sample (0.3mm wide; 0.013 mm thick) was ordered in 1990 from = a=20 ISOTECH in the Netherlands. THANKS.
 
Iain
 
*********************************************
Dr Iain=20 Robertson
Quaternary Dating Research Unit,
CSIR Environmentek, PO = Box=20 395,
0001 Pretoria, SOUTH AFRICA.
 
Tel   + 27 12 841 2300
Fax  + 27 12 349=20 1170
*********************************************
--=_663C0EAF.D4B5D3F9-- =========================================================================== 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.