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Radiocarbon dates - from the horses mouth - Printable Version +- BAJR Federation Archaeology (http://www.bajrfed.co.uk) +-- Forum: BAJR Federation Forums (http://www.bajrfed.co.uk/forumdisplay.php?fid=3) +--- Forum: The Site Hut (http://www.bajrfed.co.uk/forumdisplay.php?fid=7) +--- Thread: Radiocarbon dates - from the horses mouth (/showthread.php?tid=4118) |
Radiocarbon dates - from the horses mouth - kevin wooldridge - 15th October 2011 Actually I would take columns 1 and 2 into serious consideration. For all of the talk on this thread about the calibration of C14 dates and how that might alter the date range, to my mind, the most important aspect is ensuring that the sample from which the date is obtained can be accurately provenanced and secured within the site sequence....otherwise it's a random date 'full of sound and fury but signifying nothing' as someone more famous than I might once have writ... Radiocarbon dates - from the horses mouth - maurizio feo - 16th October 2011 That's very true: but it also depends on where we are treating the matter. If it is at an Archaeology convention all columns are obviously important a cannot be overlooked. But here - in the presence of one who has to double check his sentences AND is even worse off in Archaeology (that's me, of course!) who has a very low level problem in understanding the very basic things - perhaps a somewhat more "casual" attitude may be allowed, I hope. I may add that, regerttably, strict scientific methods (and mainly their high costs) are not very popular in Sardinia, so they are less frequently applied then elsewhere... And when they are applied, more likely they are performed by foreign labs. There are other obstacles, of course: for instance dendrochronology still may not count on a complete referrement series, becouse of the climate, influencing the quality of predominant trees (domestic and wild olive trees cavitate and cannot be used; other trees - such as oaks - where harvested for wood or do not live long enough)... But we might discuss this later, I hope... In the Barumini Nuraghe (called "Su Nuraxi", as if it were the only one) a thick piece of wood stuck rather high in the main dome of the building was used for C14 dating. Initially it was thought to be "a lever, or tool that could not be extracted after its use by the builders", but the most probable hypothesis is that it was a support to a larger wooden structure, a floor possibly, that helped better utilize the vertical space of the high dome. Radiocarbon dates - from the horses mouth - Jack - 17th October 2011 maurizio feo Wrote:OK, thank you both for the encouragement... The crux is: Is column 4 the calibrated radiocarbon age or the uncalibrated age? To calibrate a radiocarbon measurement of 'age at death' of the sample to a calendar date it has to be filtered through a calibration curve. Also why are you subtracting 1995 from 4180? Is this a reference to BP (before present)? If so BP measurements are take from before 1950. Column 6 is the calibrated date range which is an expression of a statistical function. Not just a simple high and low limits of the date. It would make more sense if you saw the density plots, which are graphs showing a visual representation of the date range. Hope this helps. Radiocarbon dates - from the horses mouth - P Prentice - 17th October 2011 maurizio feo Wrote:OK, thank you both for the encouragement... given calib uses BP dates then 4180 means before 1950 and this is only 60 years ago so wont much figure the calibrated range you state as 3333 BC - 2915 BC and is no way anything to do with 1600 -1300 bc (uncalibrated) so i can only summise that these are calibrated 3333 - 2915 BP which puts you in the right ball-park (correct BC date) what you dont say is if any of the dates in the table have been combined in a sequence to allow one to influence another remember BC is calibrated and bc is not this being said the contentious Su Nuraxi date of i believ 1478 BC is on a single piece of olive wood found in the structure and only dates the wood not the structure good luck Radiocarbon dates - from the horses mouth - maurizio feo - 17th October 2011 Thank you, Jack and Prentice! And sorry for the mess I made (both miscalculating and miswriting, 1950 turning into 1995, for reasons unknown, probably just confusion). I didn't mean to waste your time in such a silly way... And thank you for your patience! Now, please allow for some time, enough for me to ponder your suggestions and look ober these figures again.... I also just found another work , more recent than Tykot's (regrettably it's in Spanish, so it will take a lot of sweat): RUBINOS, A., y RUIZ-G?LVEZ, M., "La cronologia absoluta del periodo nuragico a la luz del proyecto Pranemuru", TRABAJOS DE PREHISTORIA 60, n.o 2, 2003, pp. 91 a 115. This is the link (I hope it is OK to post it), in case some of you understand the language: http://tp.revistas.csic.es/index.ph...e/view/83/83 I will be back! :face-approve: Radiocarbon dates - from the horses mouth - Jack - 18th October 2011 No worries.......:face-approve: |