========================================================================= Date: Wed, 1 Nov 2000 16:07:46 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Kim T Elliott Subject: Accuaracy question Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Dear listmembers, I received the following questions by email today. If anyone would like to reply, I'll forward the responses to Roger. Cheers, Kim >Why do we constantly hear about dates millions of years old >when C14 dating is only good for < 60,000 years ? > >How can you measure the radiation of a sample older than 12,000 years ? >shouldnt all the C14 be depleted ? > >Thanks to your response > >Roger ------------------------------ Kimberley Tanner Elliott RADIOCARBON Managing Editor Univ. of AZ, Dept. of Geosciences 4717 E. Fort Lowell Road, Rm. 104 Tucson, AZ 85712-1201 USA TEL: +1 520 881-0857; FAX: +1 520 881-0554 www.radiocarbon.org =========================================================================== 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, 1 Nov 2000 16:40:15 -0800 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Bill Doleman Subject: Re: Accuaracy question In-Reply-To: <3.0.6.32.20001101155709.00e2fa00@radiocarbon.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Wed, 1 Nov 2000, Kim T Elliott wrote: > I received the following questions by email today. If anyone would like to > reply, I'll forward the responses to Roger. > > >Why do we constantly hear about dates millions of years old > >when C14 dating is only good for < 60,000 years ? > >How can you measure the radiation of a sample older than 12,000 years ? > >shouldnt all the C14 be depleted ? Well, I'm hardly qualified to offer a definitve answer to this question. Obviously, however, the short answer is that C-14 dating is only one of a whole slew of radiometric dating methods, whose "maximum datable age" is a function of the radioactive decay process upon which it is based. Examples include Potassium-argon, and Uranium-thorium (?) dating of rocks. The only reason I'm chiming in is that I'd love to see a more comprehensive list and some references to good overviews of the subject. Cheers, Bill +=====================================+ | William Doleman, PhD | | Principal Investigator | | University of New Mexico | | Office of Contract Archeology | | 1717 Lomas NE | | Albuquerque, NM 87131 | | (505) 277-5853 || wdoleman@unm.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: Thu, 2 Nov 2000 08:08:56 -0600 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "Zimmer, Jeff" Subject: Re: Accuaracy question MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" As a rough approximation after about 10 half-lives the radioactivity of any radioisotope is pretty much depleted. C-14 has a half-life of ~5700 years so C-14 dating is good to roughly 50,000 to 60,000 years (not sure where the figure 12,000 comes from). But C-14 is not the only radioisotope around. There are lots of others U, Th, etc. with longer half-lives that can be used for dating by measuring the degree of equilibrium between the parent isotope and progeny. Plus there are lots of other ways to estimate the age of various artifacts. Cheers -----Original Message----- From: Kim T Elliott [mailto:Kim.Elliott@RADIOCARBON.ORG] Sent: November 1, 2000 5:08 PM To: C14-L@LISTSERV.ARIZONA.EDU Subject: Accuaracy question Dear listmembers, I received the following questions by email today. If anyone would like to reply, I'll forward the responses to Roger. Cheers, Kim >Why do we constantly hear about dates millions of years old >when C14 dating is only good for < 60,000 years ? > >How can you measure the radiation of a sample older than 12,000 years ? >shouldnt all the C14 be depleted ? > >Thanks to your response > >Roger ------------------------------ Kimberley Tanner Elliott RADIOCARBON Managing Editor Univ. of AZ, Dept. of Geosciences 4717 E. Fort Lowell Road, Rm. 104 Tucson, AZ 85712-1201 USA TEL: +1 520 881-0857; FAX: +1 520 881-0554 www.radiocarbon.org =========================================================================== 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: Thu, 2 Nov 2000 09:52:40 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: John F Wehmiller Subject: Re: Accuaracy question In-Reply-To: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII This reference should be of value for the general discussion of Quaternary dating methods- it covers 14C, U-Th, Ar/K, and many others - principles, methods, and examples of applications. Noller, J.S., Sowers, J.M., and Lettis, W.R., eds., Quaternary Geochronology, Methods and Applications, American Geophysical Union Reference Shelf, v. 4, p. 187-222. See AGU Web page for further info. ****************************************************** John F. Wehmiller, Dept. of Geology, Univ. of Delaware Newark, DE USA 19716 302-831-2926; fax 302-831-4158 http://www.geology.udel.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: Thu, 2 Nov 2000 08:54:27 -0600 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: David Carlson Subject: Re: Accuaracy question In-Reply-To: <3.0.6.32.20001101155709.00e2fa00@radiocarbon.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Probably you will get many answers, but here's two brief ones: The older dates are based on other radiometric dating methods, for example, potassium-argon and uranium thorium. I'd suggest the following web sites: http://www.erinet.com/jwoolf/rad_dat.html Radiometric Dating (this is a basic introduction to radiocarbon, uranium-thorium, and potassium-argon). http://pubs.usgs.gov/gip/geotime/radiometric.html Geologic Time: Radiometric Time Scale by the USGS http://www.talkorigins.org/faqs/isochron-dating.html Isochron Dating by Chris Stassen on the Talk.Origins Archive. The second question is a common misconception about how radioactive decay works. The rate of decay is constant which means that it operates on whatever is left not what you started with. If you had $100 dollars invested in an internet startup that was losing 50% of its value every year, after the first year you would have only $50 left. The second year you would have $25 left NOT $0 because 50% of $50 is $25. Radioactive decay works the same way. =========================================================================== 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, 6 Nov 2000 07:39:01 +0200 Reply-To: Jake Jacobson Sender: Radiocarbon Mailing List From: Jake Jacobson Organization: McGregor Museum Subject: Re: Accuaracy question MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit "....(not sure where the figure 12,000 comes from). "..... This figure comes from a fundamentalist position that the earth is only 10 or 12 thousand years old and that C14 and other dating methods are in error. I once sat thru a tedious lecture on this given by an engineer friend who had been born again. He could prove (using fancy graphs, data, etc, and a jump in logic) that all dates older than 10K were wrong. Cant remember the details now. ___________________________________________ Leon Jacobson Tel: 053-842-0099 McGregor Museum fax: 053-842-1433 P.O.Box 316 e-mail: jake@museumsnc.co.za 8300 Kimberley SOUTH AFRICA Web page: www.museumsnc.co.za/archaeology/arcometr.htm "Those who steal from private individuals spend their lives in stocks and chains: those who steal from the public treasure go dressed in gold and purple" Cato the Censor =========================================================================== 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, 7 Nov 2000 12:18:35 -0600 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Chuck Blatchley Organization: Pittsburg State University Subject: Re: Accuracy question MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Jake Jacobson wrote: > > "....(not sure where the figure 12,000 comes from). "..... > ... a tedious lecture on this given by an engineer friend ... 6,000 years B.P. comes from Bishop Ussher's calculation. Engineers use a safety factor of 2x. :) Chuck Blatchley =========================================================================== 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, 8 Nov 2000 16:50:57 +1300 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Tom Higham Subject: Pretreatment query Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" ; format="flowed" I am interested in hearing from anyone who has any advice or experience on the removal of polyethylene-glycol from wood which has had this consolidant used on it for the purpose of conservation of waterlogged artefacts. If anyone can help out with email, I will collate anything useful and send to the list for those interested. cheers for now, -------------------------------------------- Dr Tom Higham, Deputy Director, Radiocarbon Dating Laboratory, University of Waikato, Private Bag 3105, Hamilton, NEW ZEALAND. Waikato Radiocarbon Lab WWW Server:- http://www.radiocarbondating.com Radiocarbon WEB-info:- http://www.c14dating.com =========================================================================== 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, 8 Nov 2000 10:28:31 +0200 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Siep Talma Subject: Re: Accuaracy question Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=_93C8ADDE.B6D7FF40" 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. --=_93C8ADDE.B6D7FF40 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable I once worked through a paper from the Creation Research Society proving = that the world was 7000 years old. The assumptions were (if I remember correctly) that the world was created = with a different (much smaller) carbon reservoir. The big flood 5000 years = ago released more carbon and so the atmospheric build up rate decreased to = the levels we have now. This model means that all dates up to 5000 old are = more or to that we are using. Older dates are compressed into the = 7000-5000 slot. A histogram of available dates then shows low frequency of = pre-flood samples and high frequency post-flood. This proves the model is = correct. It is a fun model to play with. You can assume other dates for the = creation and the big flood and prove that those particular dates are = correct. A nice example of circular reasoning. Now that we have convincing = tree ring chronologies 10 000 or 12 000 are probably more popular dates. It would be one of the fun papers to write. Siep Talm AS TALMA Quaternary Dating Research Unit Environmentek-CSIR PO Box 395 PRETORIA 0001 South Africa Ph +2712 841-3402 Fax +2712 349-1170 Email Stalma@csir.co.zaa >>> Jake Jacobson 06.11.2000 07:39:01 >>> "....(not sure where the figure 12,000 comes from). "..... This figure comes from a fundamentalist position that the earth is only 10 or 12 thousand years old and that C14 and other dating methods are in = error. I once sat thru a tedious lecture on this given by an engineer friend who had been born again. He could prove (using fancy graphs, data, etc, and a jump in logic) that all dates older than 10K were wrong. Cant remember the details now. ___________________________________________ Leon Jacobson Tel: 053-842-0099 McGregor Museum fax: 053-842-1433 P.O.Box 316 e-mail: jake@museumsnc.co.za 8300 Kimberley SOUTH AFRICA Web page: www.museumsnc.co.za/archaeology/arcometr.htm "Those who steal from private individuals spend their lives in stocks and chains: those who steal from the public treasure go dressed in gold and purple" Cato the Censor =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. --=_93C8ADDE.B6D7FF40 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Description: HTML

I once worked through a paper from the Creation Research = Society=20 proving that the world was 7000 years old.
 
The assumptions were (if I remember correctly) that the world was=20 created with a different (much smaller) carbon reservoir. The big = flood=20 5000 years ago released more carbon and so the atmospheric build up = rate=20 decreased to the levels we have now. This model means that all dates up to = 5000=20 old are more or to that we are using. Older dates are compressed into = the=20 7000-5000 slot. A histogram of available dates then shows low frequency = of=20 pre-flood samples and high frequency post-flood. This proves the model = is=20 correct.
 
It is a fun model to play with. You can assume other dates for the = creation=20 and the big flood and prove that those particular dates are correct. A = nice=20 example of circular reasoning. Now that we have convincing tree ring=20 chronologies 10 000 or 12 000 are probably more popular dates.
 
It would be one of the fun papers to write.
 
Siep Talm
 
AS TALMA
Quaternary Dating Research Unit
Environmentek-CSIR
P= O Box=20 395
PRETORIA    0001
South Africa
Ph =20 +2712     841-3402      = =20 Fax  +2712    349-1170
Email  Stalma@csir.co.zaa
>>> Jake Jacobson <jake@museumsnc.co.za> 06.11.2000 = 07:39:01=20 >>>
"....(not sure where the figure 12,000 comes from).=20 ".....

This figure comes from a fundamentalist position that the = earth is=20 only 10
or 12 thousand years old and that C14 and other dating methods = are in=20 error.
I once sat thru a tedious lecture on this given by an engineer = friend=20 who
had been born again. He could prove (using fancy graphs, data, etc, = and=20 a
jump in logic) that all dates older than 10K were wrong. Cant = remember=20 the
details now.

___________________________________________
L= eon=20 Jacobson           &= nbsp;           =20 Tel: 053-842-0099
McGregor=20 Museum           &nb= sp;      =20 fax: 053-842-1433
P.O.Box=20 316            =             &nb= sp;  =20 e-mail: jake@museumsnc.co.za
8300 Kimberley
SOUTH AFRICA
Web = page:=20 www.museumsnc.co.za/archaeology/arcometr.htm

"Those who steal = from=20 private individuals spend their lives in stocks and
chains: those who = steal=20 from the public treasure go dressed in gold and
purple"
Cato the=20 Censor

=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=20 unsubscribe from this list, send the command SIGNOFF C14-L=20 to
LISTSERV@LISTSERV.ARIZONA.EDU, or send a request to=20 C14-L-request@LISTSERV.ARIZONA.EDU.

--=_93C8ADDE.B6D7FF40-- =========================================================================== 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, 8 Nov 2000 16:30:55 +0100 Reply-To: fbruhn@leibniz.uni-kiel.de Sender: Radiocarbon Mailing List From: Frank Bruhn Organization: Leibniz-Labor, Universitaet Kiel, Germany Subject: Re: Pretreatment query MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Tom and others interested, we have recently performed some tests on oak wood of known age (ca. 8 ka BP), treated with PEG the same way as museum conservators do with their objects (i.e. soaked with PEG for 6 months or so). The result was that for PEG (petroleum-based, apparent age of >58 ka BP in our measurements) routine AAA treatment already yielded satisfactory results within 2 sigma of the original age. We have summarized the results and those for other conservation agents (rubber glue, wood glue, epoxy, paraffin, beeswax etc.) in a brief paper to be published in the Procedings of the Jerusalem Radiocarbon Conference. Furthermore, there is an interesting book available about conservation materials and their solvents which I think is worth having on the shelf: Horie, C.V. (1987): Materials for Conservation, 281 pp, Architectural Press, Oxford. Cheers, Frank Tom Higham wrote: > I am interested in hearing from anyone who has any advice or > experience on the removal of polyethylene-glycol from wood which has > had this consolidant used on it for the purpose of conservation of > waterlogged artefacts. > > If anyone can help out with email, I will collate anything useful and > send to the list for those interested. > > cheers for now, > -------------------------------------------- > Dr Tom Higham, > Deputy Director, > Radiocarbon Dating Laboratory, > University of Waikato, Private Bag 3105, > Hamilton, NEW ZEALAND. > Waikato Radiocarbon Lab WWW Server:- http://www.radiocarbondating.com > Radiocarbon WEB-info:- http://www.c14dating.com > > ============================================================================ > 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. Frank Bruhn (Diplom-Geologe) Leibniz-Labor fuer Altersbestimmung und Isotopenforschung Christian-Albrechts-Universitaet Tel: +49 431 880-7391 Max-Eyth-Str. 11-13 Fax: +49 431 880-3356 24118 Kiel, Germany E-Mail: fbruhn@leibniz.uni-kiel.de http://www.uni-kiel.de/leibniz =========================================================================== 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, 8 Nov 2000 16:52:33 +0100 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Mark Van Strydonck Subject: Re: Pretreatment query MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit We pulverised the sample in a blender, washed it several times with hot water and than transformed the wood into pure cellulose. We followed the cleaning process by infra red spectrometry. After the treatment the infrared spectrum only showed cellulose bands and no polyethylene-glycol anymore. -----Oorspronkelijk bericht----- Van: Tom Higham Aan: C14-L@LISTSERV.ARIZONA.EDU Datum: woensdag 8 november 2000 16:00 Onderwerp: Pretreatment query >I am interested in hearing from anyone who has any advice or >experience on the removal of polyethylene-glycol from wood which has >had this consolidant used on it for the purpose of conservation of >waterlogged artefacts. > >If anyone can help out with email, I will collate anything useful and >send to the list for those interested. > >cheers for now, >-------------------------------------------- >Dr Tom Higham, >Deputy Director, >Radiocarbon Dating Laboratory, >University of Waikato, Private Bag 3105, >Hamilton, NEW ZEALAND. >Waikato Radiocarbon Lab WWW Server:- http://www.radiocarbondating.com >Radiocarbon WEB-info:- http://www.c14dating.com > >=========================================================================== = >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: Thu, 23 Nov 2000 00:12:45 +0000 Reply-To: Doug Weller Sender: Radiocarbon Mailing List From: Doug Weller Subject: No need for calibration curves anymore? Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hello C14-L, I'm told that there is a new method of dating that "goes directly from the measured C12/C14 ratio to a calibrated age. It does not require the initial calculation of a carbon date corrected from a calibration curve." The source of this claim is See: http://www.radiocarbon.com/calendar.htm "Our calibrations are calibrated using the newest calibration data as published in Radiocarbon, Vol. 40, No. 3, 1998 using the cubic spline fit mathematics as published by Talma and Vogel, Radiocarbon, Vol. 35, No. 2, pg 317-322, 1993: A Simplified Approach to Calibrating C14 Dates. It is always important to quote the data source and mathematics with your interpretations" I don't quite understand how this can work, can anyone explain it in layman's terms? Thanks. One subsidary question -- is it common for labs to provide calibrated dates when they test, or do they normally just provide the C14 dates? This is all stemming from a discussion of the dating of the mortar in a tower in Newport Rhode Island by Heineneier and Jungner. Thanks. Doug Weller -- Doug Weller Moderator, sci.archaeology.moderated Submissions to:sci-archaeology-moderated@medieval.org Doug's Archaeology Site: http://www.ramtops.demon.co.uk Co-owner UK-Schools mailing list: email me for details =========================================================================== 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, 27 Nov 2000 15:12:50 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Ken Cole In-Reply-To: <000401c0499b$e8a8a9a0$e101a8c0@PC003.kikirpa> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Radiocarbon List: I have been trying to find a C14 yr B.P. scale and a Calendar year scale that can be graphed along an axis of a diagram as two scales along one axis. One scale would be set at a certain regular interval (such as 1000 years/inch) while the other would be gradational with variable lengths. At certain times it would be useful for either one to be the standard regular length that data is plotted by while the other remains merely as a guide for the reader. To do this I could construct my own data set of paired dates by calibrating a series of dates, but somebody else surely must have already done a complete job on this. I would like to use these axis scales in SigmaPlot and Tilia. Either program could likely be made to convert a paired series of intercepts into fixed and gradational scales. Ken Cole ****************************************** Kenneth L. Cole Colorado Plateau Field Station U.S. Geological Survey, P.O. Box 5614, Bldg. 24 Northern Arizona University Flagstaff, AZ 86011-5614 Phone:(520)556-7466 ext. 230 FAX:(520)556-7500 E-mail: Kenneth.Cole@nau.edu Personal Web Pages: http://www.usgs.nau.edu/staff/kcole.html Office Web Pages: http://www.usgs.nau.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: Tue, 28 Nov 2000 09:03:40 -0600 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: David Carlson In-Reply-To: <4.1.20001127145344.00b5f7d0@jan.ucc.nau.edu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit The data files that come with CALIB should be enough to create the scale you are describing, but it will be a bit more complicated than you describe since a single radiocarbon age can intercept more than one calendar date. You will have to construct calendar scale that has variable lengths AND loops back on itself. -------------------- David L. Carlson Associate Professor of Anthropology and Head Texas A&M University College Station, TX 77843-4352 (409) 847-9248 =========================================================================== 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, 28 Nov 2000 16:15:13 +0000 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Paula Reimer Subject: Re: No need for calibration curves anymore? MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Dear Doug, A calibration curve is still a necessary ingredient in producing a calibrated age range from a radiocarbon date. It would be possible to by-pass the calculation of a radiocarbon age if you used the C12/C14 ratios of the calibration dataset for the calibration, but I can't see the advantage. The spline described by Talma and Vogel (1993) is one way of smoothing the calibration curve. The calibrated age ranges produced are not much different than those obtained with linear interpolation between the calibration data points. I prefer to use a moving average to smooth the calibration curve because it can be chosen to match the actual sample growth span and thereby reflects the average 14C level of the atmosphere under which the sample was formed. For instance, if a sample took 60 years to form, a 60 year (6 point) moving average of the decadal calibration curve would be used. Many radiocarbon labs do provide calibrated ages, but others do not. We now have an on-line calibration program at www.calib.org which is relatively easy to use for those who wish to calibrate their own radiocarbon ages. Best wishes, Paula Reimer Doug Weller wrote: > Hello C14-L, > > I'm told that there is a new method of dating that "goes directly from the > measured C12/C14 ratio to a calibrated age. It does not require the > initial calculation of a carbon date corrected from a calibration > curve." > > The source of this claim is > See: http://www.radiocarbon.com/calendar.htm > > "Our calibrations are calibrated using the newest calibration data > as published in Radiocarbon, Vol. 40, No. 3, 1998 using the cubic > spline fit mathematics as published by Talma and Vogel, > Radiocarbon, Vol. 35, No. 2, pg 317-322, 1993: A Simplified > Approach to Calibrating C14 Dates. It is always important to quote > the data source and mathematics with your interpretations" > > I don't quite understand how this can work, can anyone explain it > in layman's terms? > > Thanks. > > One subsidary question -- is it common for labs to provide > calibrated dates when they test, or do they normally just provide > the C14 dates? > > This is all stemming from a discussion of the dating of the mortar > in a tower in Newport Rhode Island by Heineneier and Jungner. > > Thanks. > > Doug Weller > > -- > Doug Weller Moderator, sci.archaeology.moderated > Submissions to:sci-archaeology-moderated@medieval.org > Doug's Archaeology Site: http://www.ramtops.demon.co.uk > Co-owner UK-Schools mailing list: email me for details > > ============================================================================ > 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. Paula J. Reimer School of Archaeology & Palaeoecology Queen's University of Belfast Belfast BT7 1NN Northern Ireland Phone: 44-(0)28-9027-3980 FAX: 44-(0)28-9031-5779 e-mail: p.j.reimer@qub.ac.uk http://www.qub.ac.uk/arcpal/staff/reimer =========================================================================== 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.