te: Fri, 3 Mar 1995 00:14:25 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "N. Phil Peterson" Subject: Request for information I am new to the Internet. I am interested in finding basic information on radio isotope dating techniques; journals, good texts, labs that have services, scientists working with these techniques. I am a fish biologist with a developing interest in paleo-ecology and would appreciate any information others may offer. Thanks. ========================================================================= Date: Wed, 15 Mar 1995 06:13:55 -1000 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "Thomas S. Dye" Subject: AMS and stable carbon isotope ratios An archaeologist working with radiocarbon dates is unable to find good advice on the interpretation of stable carbon isotope ratios reported with AMS dates. Initially, my colleagues and I were puzzled by the fact that our AMS dates were reported without d13C. We soon found that if we pestered the radiocarbon lab we could get a report of d13C with our AMS dates. Repeated pestering yielded the comment that the d13C values reported with AMS dates were not commensurate with the d13C values that are routinely reported with non-AMS dates. Additional pestering and some time in the library both failed to yield information on how the two types of d13C values differ. We have been led to understand that d13C reported with AMS dates includes the effects of fractionation in nature and in the laboratory preparation of the sample for AMS dating. Ideally, we would like to be able to correct for the laboratory effect, if only in a probabilistic way, because in many cases where we have small samples we are also interested in the natural d13C values. In the small sample case must we choose between a date and a natural d13C value? I would appreciate any advice you might offer, and especially references to relevant literature. Tom Dye, Honolulu ========================================================================= Date: Thu, 16 Mar 1995 11:31:12 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Timothy Jull Subject: Re: AMS and stable carbon isotope ratios re: Stable isotope ratios Our AMS laboratory measures d13C in the conventional way using a mass spectrometer. The d13C values are reported as appropriate. For some samples it may not be necessary to measure d13C to get the age. Some of the information you presented concerning the idea d13C data are either "degraded" from the original data, or are less reliable, aren't in my opinion correct, at least for Arizona AMS dates. The d13C is used to correct the 14C dates to -25 per mil. They are also often valuable for stable-isotope information which helps in data interpetation. d13C represents the stable-isotope value of the sample, as 14C represemnents the 14~C age oif the sample. Some labs which measure 13C directly on the AMS claim that additional information regarding "fractionation" of targets can be extracted. At least at Arizona, this is not the case. Tim Jull Univ of Arizona AJTJULL@ccit.arizona.edu ========================================================================= Date: Thu, 16 Mar 1995 11:05:50 -1000 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "Thomas S. Dye" Subject: Re: AMS and stable carbon isotope ratios In-Reply-To: <199503161834.LAA49928@curacao.ccit.arizona.edu> Tim, Thank you for your reply to my query. I am pleased to know that it is possible to measure d13C in the conventional way with small samples intended for AMS dating. It is useful to know that the Arizona lab follows this conventional procedure. I am a bit puzzled why all AMS labs don't follow this procedure. It is my understanding that d13C measured directly on the AMS gives a value that is not commensurate with t From: Karl von Reden Subject: Re: AMS and stable carbon isotope ratios In-Reply-To: <199503162113.OAA48481@curacao.ccit.arizona.edu>; from "Thomas S. Dye" at Mar 16, 95 11:05 am Another comment on AMS d13C numbers. Like the Arizona AMS facility we (the NOSAMS facility at Woods Hole) report d13C values measured separately with our stable isotope mass spectrometers. However, as one of the two operating AMS facilities, so far, that can simultaneously accelerate all 3 carbon isotopes, we continuously obtain C-13/C-12 ratios along with our C-14 values. These ratios are generally of a precision in the order of 0.2% (much less precise than the stable isotope mass spectrometer results). Their accuracy, however, will be as good as with any other method, if any kind of fractionation is corrected for in comparison with standards measured concurrently. We use the AMS d13C numbers for internal purposes only (e.g. control of the system parameters and tuning). There may be a use of the AMS d13C values, if precision can be relaxed, for specific circumstances (i.e. very small samples). Karl von Reden National Ocean Sciences AMS Facility Woods Hole, MA ========================================================================= Date: Tue, 21 Mar 1995 12:00:43 -0800 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Mark Hall Subject: Re: AMS and stable carbon isotope ratios Along this line, when using the CALIB 3.0 program, should one calibrate using d13C values for terrestrial samples? I have some uncalibrated dates and the d13C values; to give an idea, the C-14 dates range from 1665 BP to 1315 BP with a standard deviation of +/-70. For the 9 samples, the d13C values range from -21.14 to -24.36. Thanks for any advice. Mark Hall hall@qal.berkeley.edu Dept. of Anthropology UC Berkeley Berkeley, CA 94720 ========================================================================= Date: Tue, 21 Mar 1995 13:57:35 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: MANLEY WILLIAM FREDERICK Subject: Re: AMS and stable carbon isotope ratios I am sure that Paula Reimer and others could provide useful information also, but with the Calib program it is very important to distinguish between "conventional radiocarbon ages" and 13C-uncorrected dates. The former follow the international convention set by Stuiver and Reimer (1977). Thus, they are 13C-corrected, using a measured or assumed 13C value, normalized to a base of del13C=-25 per mil (this is the value used for normalization, not the assumed value of the dated sample). The Calib program calibrates "conventional radiocarbon ages" without any special input of 13C values; ie., without the extra option utilized in the program to account for 13C values. Some, but very few, labs still do not report conventional radiocarbon ages. For these dates that are clearly not 13C-corrected (otherwise known as "machine dates"), you will have to take the extra step in Calib of entering the 13C value and an estimate of the error associated with that value. Nearly all radiocarbon labs, however, since ca. 1978, have determined conventional radiocarbon ages. In some cases it might require going to the original reporting form, date lists, or contacting labs directly to determine if your dates are conventional radiocarbon ages. I hope this is helpful. Regards, Bill Manley ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ William F. Manley Institute of Arctic and Alpine Research University of Colorado Tel: (303) 492-5075 Fax: (303) 492-6388 E-mail: manleyw@ucsu.colorado.edu WWW site: http://ucsu.colorado.edu/~manleyw/Home.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ========================================================================= Date: Tue, 21 Mar 1995 14:01:54 -0800 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Paula Reimer Subject: Re: AMS and stable carbon isotope ratios In-Reply-To: <199503212000.MAA21644@snowy.qal.berkeley.edu> Bill Manley has admirably answered the question about calibrating conventional radiocarbon ages and uncorrected radiocarbon dates. I have only one correction to make. The conventional radiocarbon age was established by Stuiver and Polach (1977). By the way, CALIB 3.0.3c (DOS or MAC) is available on the Internet at the anonymous ftp site ftp.u.washington.edu (140.142.56.2) and is on the directory /public/calib. There is also information about a few bugs and workarounds and a French translation of the manual. If anyone has any problem with accessing the ftp site or needs more specific instructions, please let me know. Sincerely, Paula Reimer ****************************************************************** * \ | / * * /\ - ( ) - * * //\\ / | \ Paula J. Reimer * * ///\\\ Quaternary Research Center AK-60 * * ////\\\\ University of Washington * * ____||____ Seattle, WA 98195 * * \~~~~~~~~/ Phone: (206) 543-6327 * * \======/ FAX: (206) 543-3191 * * \====/ e-mail: pjreimer@u.washington.edu * ****************************************************************** ========================================================================= Date: Tue, 21 Mar 1995 16:14:01 -1000 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: "Thomas S. Dye" Subject: Re: AMS and stable carbon isotope ratios In-Reply-To: <199503201737.KAA20383@curacao.ccit.arizona.edu> Karl von Reden, Thank you for your post on this subject. Your reply raises two questions, and I'd appreciate any further help you might offer. First, if I understand correctly, there might be situations where a very small sample is large enough for AMS dating, but not for AMS dating *and* measuring d13C in the mass spectrometer. Is there a useful guide to the size of this kind of sample? Here, my goal would be to collect sufficient material for both AMS date and a measurement of d13C in the mass spectrometer. Second, you note that only two laboratories can count all three carbon isotopes simultaneously, but it is my impression that several AMS laboratories report d13C measured on the AMS, rather than the mass spectrometer. Is my impression wrong? Or, is it possible to measure d13C on the AMS without counting all the isotopes simultaneously? Thanks, Tom ========================================================================= Date: Wed, 22 Mar 1995 10:00:03 EST Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Karl von Reden Subject: Re: AMS and stable carbon isotope ratios In-Reply-To: <199503220221.TAA46225@curacao.ccit.arizona.edu>; from "Thomas S. Dye" at Mar 21, 95 4:14 pm Clarification: Of course it is possible to measure C-13/C-12 with the sequential injection method (with similar precision/accuracy as with the simultaneous method). We don't think that reporting these numbers, routinely, adds much (if anything) to the main result of AMS: C-14. As to small samples: Probably almost every AMS lab around is presently working on reducing required sample sizes. No final answer is out, yet. Karl von Reden (KVONREDEN@WHOI.EDU) NOSAMS Facility Woods Hole, MA ========================================================================= Date: Thu, 23 Mar 1995 11:15:47 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: David Sewell Subject: RADIOCARBON guide to wp and graphics files We've just produced a four-page set of guidelines for authors of articles submitted to RADIOCARBON describing the formats and techniques we recommend for both word processor and graphics files. It is tailored to our own specific use in converting files to FrameMaker, the publishing program we use, but you may also find it useful for general guidelines to preparing documents that will translate well into other computer formats as well. There's also an overview of the difference between vector and bitmap graphics, with recommendations about which format is appropriate for which kind of figure, that should be applicable to most publications that accept computer graphics files for printing. We'll be including a copy of these guidelines with manuscripts we return to authors in the future, but if you'd like a copy now, send a self-addressed, stamped envelope to RADIOCARBON at the address in the .sig below (or send an International Response Coupon from outside the US). OR, for free, download an .EPS version of the file that you can print out on any PostScript printer using either ftp or a WWW browser: ftp: connect to packrat.aml.arizona.edu, file is pub/formats.eps www: ftp://packrat.aml.arizona.edu/pub/formats.eps -- David Sewell, Assistant Editor RADIOCARBON: An International Journal of Cosmogenic Isotope Research Department of Geosciences, University of Arizona 4717 E. Ft. Lowell Rd., Tucson, Arizona 85712 USA Telephone: 1-520-881-0857 Fax: 1-520-881-0554 General e-mail address: c14@packrat.aml.arizona.edu, WWW server: http://packrat.aml.arizona.edu/ ========================================================================= Date: Fri, 24 Mar 1995 09:45:40 +0200 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Israel Carmi Subject: Calibrations Southon & Brown (Science 267, 256 (1995)) calibrate the data given by Zielinski et.al. (Science 264, 948 (1994)) for the GISP ice core record of volcanism since 7,000 BC, to reach conclusions that are differnt from those of Zielinski et.al. who had used conventional radiocarbon ages in their analysis. The calibrated data of Southon & Brown raises two points: 1. The calibration of, e.g. Black Peak (4435+-300 ybp) is given as 3512-3396: 3394-2858: 2817-2687: 2681-2670 BC. The corresponding weights of these ranges (not given in the paper) are .12 .72 .13 .01. They are NOT equal and are essential for evaulating a reasonable age range. 2. The intervals between the four ranges are, respectively, 2, 31 and 6 years. They are negliglble compared to the 300 years quoted error in the conventional age. So: should we reach a consnesus on how to evaluate reasonable age ranges in such cases and decide when age ranges shold be lumped together? Israel Carmi ========================================================================= Date: Sat, 25 Mar 1995 09:57:37 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Naomi Holcomb Subject: list Dear Sir: I have been receiving your list mailings, and I enjoy them very much. Do y ou have an arrangement whereby I can receive them in DIGEST FORM? Please let me hear from you. Thank y ou very much. Sincerely, Naomi Holcomb ========================================================================= Date: Mon, 27 Mar 1995 03:16:49 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Frederick Cryer Organization: Teologisk Fakultet Subject: query Hi team-- I'm looking for information on recent C-14 analyses of the Dead Sea Scrolls. Any joy? Cheers, Fred ========================================================================= Date: Mon, 27 Mar 1995 09:42:31 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: David Sewell Subject: Re: list In-Reply-To: <199503251458.HAA32068@curacao.ccit.arizona.edu> from "Naomi Holcomb" at Mar 25, 95 09:57:37 am >I have been receiving your list mailings, and I enjoy them very much. > >Do y ou have an arrangement whereby I can receive them in DIGEST FORM? > Send the following message to listserv@listserv.arizona.edu: SET C14-L DIGEST You should get a confirmation that you will be receiving postings as a digest. I set up the digest to mail on a weekly basis. You're the first person I know of who has been interested in digest mailings, so let me know if it doesn't seem to be working. David Sewell -- David Sewell * dsew@packrat.aml.arizona.edu | "Seekers for gold dig much RADIOCARBON, Dept of Geosciences, U of Arizona | earth, and find little gold." WWW: http://packrat.aml.arizona.edu/~dsew/ | --Heraclitus Tel. 1-520-881-0857 Fax 1-520-881-0554 | ========================================================================= Date: Mon, 27 Mar 1995 10:12:34 -0700 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: David Sewell Subject: Re: list (C14-L: correction) In-Reply-To: <199503271643.JAA22977@curacao.ccit.arizona.edu> from "David Sewell" at Mar 27, 95 09:42:31 am Sorry, all. That message about the Digest option for the radiocarbon list, C14-L, was meant to go to a single subscriber. Even listowners can make stupid mistakes, obviously. However, let me just clarify for everyone's benefit: if you would rather receive the Listserv mailings in a "package" on a weekly basis, rather than as often as they are posted, send e-mail to listserv@listserv.arizona.edu with the message body SET C14-L DIGEST The advantage of this method is that your mailbox will be less cluttered; the disadvantage is that, since the digest is mailed once a week, you may not be able to respond to time- critical requests or information. David Sewell ========================================================================= Date: Mon, 27 Mar 1995 12:50:45 -0500 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Naomi Holcomb Subject: mailing list I am on your mailing list, and I find the articles interesting. On some mailing lists, one can have the mailings sent in DIGEST FORM. Is it possible for the C14 mailing list? I would appreciate hearing from you at your earliest convenience. Thank you very much. Sincerely yours, Naomi Holcomb ========================================================================= Date: Mon, 27 Mar 1995 21:58:34 -0800 Reply-To: Radiocarbon Mailing List Sender: Radiocarbon Mailing List From: Robert Holloway Subject: Radiochemistry courses My organization (Nevada Technical Associates) has scheduled the following courses that may be of interest to this mailing list. 1. Environmental Radiochemistry, May 1-5 in Williamsburg, Virginia 2. Quality Assurance in Radiochemistry, May 8-9 in Williamsburg 3. Environmental Radiochemistry, May 29-June 2 in Vienna, Austria 4. Quality Assurance in Radiochemistry, June 5-6 in Sofia, Bulgaria If you would like to receive a brochure about these courses, please send your postal address or fax number to: NTA@IX.Netcom.com Robert Holloway Phone or Fax 702-564-2798 Previous Item Next Item Connected to Microsoft Exchange