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Are the 14C Dates of the Dead Sea Scrolls Affected by Castor Oil Contamination?
Abstract
The paper "The effects of possible contamination on the radiocarbon dates of the Dead Sea Scrolls I: castor oil" by Rasmussen et al. (2001) is discussed. Detailed analysis of the extant dates of the Dead Sea Scrolls suggests that the pre- treatment of the samples was adequate. Errors and omissions in the paper are discussed and the implications of the experiment of Rasmussen et al. (2001) are questioned.
... Rasmussen et al. (2001) also made a quantitative estimate of the amount of error that castor oil contamination of an individual Dead Sea text sample would produce after cleaning with the standard AAA pretreatment: it would be too young by a maximum of about 300 14 C yr for a sample fully saturated in castor oil. Carmi (2002) commented on our study, criticizing our analysis on 4 grounds. This critique, however, was rebutted by our reply (Rasmussen et al. 2003). ...
... (The other 2 documents in the Tucson series 14 C dated in agreement with their internal dates.) Carmi (2002) argued that the 14 C date for XHev/Se 8a "is acceptable, but not desirable, by current standards of 14 C dating" and "does not indicate a problem with castor oil contamination" because there is a small possibility the calibrated age range distribution could correspond to the historical date. However, this particular document was worked on and separately published in 1957 by Joseph Milik, a known castor oil user. ...
... Furthermore, we would venture to question the assumption that all texts not in the Rockefeller Museum were "not treated with castor oil" (Carmi 2002), an assumption also corroborated by Magen Broshi about Dead Sea texts stored at the Israel Museum: "no castor oil was applied" (Broshi 2004). To substantiate this suspicion, we would like to quote an early description of cleaning methods in use as fragments of scrolls came into the Rockefeller Museum during the early 1950s: "When pieces are selected for study, they are first put into a 'humidifier,' a glass bell containing moist sponges. ...
While kept at the Rockefeller Museum in East Jerusalem, many Dead Sea Scroll fragments were exposed to castor oil by the original team of editors in the course of cleaning the parchments. Castor oil must be regarded as a serious contaminant in relation to radiocarbon dating. If modern castor oil is present and is not removed prior to dating, the 14C dates will be skewed artificially towards modern values. In Rasmussen et al. (2001), it was shown that the standard AAA pretreatment procedure used in the 2 previous studies dating Dead Sea Scroll samples (Bonani et al. 1992; Juli et al. 1995) is not capable of removing castor oil from parchment samples. In the present work, we show that it is unlikely that castor oil reacts with the amino acids of the parchment proteins, a finding which leaves open the possibility of devising a cleaning method that can effectively remove castor oil. We then present 3 different pretreatment protocols designed to effectively remove castor oil from parchment samples. These involve 3 different cleaning techniques: extraction with supercritical CO2, ultrasound cleaning, and Soxhlet extraction - each with their own advantages and disadvantages. Our data show that the protocol involving Soxhlet extraction is the best suited for the purpose of decontaminating the Dead Sea Scrolls, and we recommend that this protocol be used in further attempts to 14C date the Dead Sea Scrolls. If such an attempt is decided on by the proper authorities, we propose a list of Scroll texts, which we suggest be redated in order to validate the 14C dates done earlier by Bonani et al. (1992) and Jull et al. (1995). © 2009 by the Arizona Board of Regents on behalf of the University of Arizona.
... Pretreatment procedures are used to remove inorganic and organic contaminations which are added to the parchment during processing. Inorganic contaminants are in the form of carbonates and bicarbonates formed following liming, egg, flour, and fish glue, and organic contaminants are in form of enamels, preservatives [8,9] and lipids from a variety of sources present within parchments that are not removed during processing or originated from microbial decay during processing, conservation, or simply from handling over time [4,5]. These contaminates/impurities cause significant errors in dating. ...
... Inorganic impurities are removed by using acid-base acid wash, varying in concentration from very mild (e.g. 0.05M HCl and 0.01M NaOH) [9,10] to much stronger (e.g. 0.5M HCl, 0.1M NaOH) [7,11]. ...
Radiocarbon dating of an archeological parchment sample was carried out by carbosorb and benzene synthesis methods. The sample, with few symbolic letters written on it, was claimed to belong to the Harappa civilization (ca. 3000-1500 BC). Objective: Carbosorb and benzene synthesis methods were optimized for radiocarbon dating of parchment samples. Radiocarbon analysis conditions were optimized for liquid scintillation counter. Methods: Archeological parchment sample and a commercial parchment sample (control sample) were processed by chemical and carbonization methods to remove inorganic and organic impurities. Samples were converted into carbamate and benzene through carbosorb and benzene synthesis systems, respectively. The conditions were optimized to achieve 74 % efficiency of carbosorb method and 78% yield in benzene synthesis system. Results and Conclusion: The pMC of both samples were calculated by using statistical templates. The fractionation in 14 C for sample was corrected for and normalized to 13 C composition of-25 ‰ PDB by measuring the 13 C composition of the sample, standard and background samples.
... Radiocarbon dating has been applied to medieval manuscripts of parchment before in multiple studies (Bonani et al. 1992;Carmi 2002;Donahue et al. 2002;Santos and García-Leon 2010;Brock 2013;Kasso et al. 2021). The primary objective of these studies has been to provide an absolute date for a historical object lacking the needed contextual information to verify its age and to provide a timeline for the historical context of the information the manuscript contains. ...
The Fragmenta membranea manuscript fragment collection at the National Library of Finland has proved challenging to date using only traditional paleography. Therefore, radiocarbon dates can contribute to the understanding of these fragments by offering a parallel natural scientific timeline for the parchment the manuscripts are written on. In this study, we apply our previously developed method for radiocarbon dating medieval manuscripts made of parchment. In total 35 datings were made from 14 separate assemblages of manuscripts, being the first systematic wide-scale application of radiocarbon dating to a collection of medieval manuscripts in order to improve their chronological proxy. Additionally, due to the fragmentary and sometimes poor condition of the manuscript fragments of Fragmenta membranea analyzed in this study, we used Fourier-transform infrared spectroscopy (FTIR) to evaluate the quality of the collagen and the presence of contaminants in the fragments affecting the radiocarbon dates. We report out radiocarbon dating results and FTIR screenings for each sample and for each manuscript assemblage, and discuss the applicability of our method in further studies of applying radiocarbon dating on objects of cultural historical interest and value. The results indicate an essential role of high-quality samples and multiple measurements to interpret the radiocarbon dating results.
... carbonates formed following liming, egg, flour, and fish glue, although many of these may be of the same age as the parchment), and conservation materials applied subsequently. The effective removal of castor oil applied to the Dead Sea Scrolls prior to dating, for example, has been the subject of much discussion (Rasmussen et al. 2001(Rasmussen et al. , 2003(Rasmussen et al. , 2009Carmi 2002). ...
A range of pretreatment methods was applied to 6 known-age historical parchments to investigate the most suitable methods for effectively removing contamination and ensuring accurate radiocarbon dates while minimizing unnecessary destruction of potentially valuable historical documents. The methods tested included an acid wash, different concentrations of acid-base-acid (ABA) pretreatments, the current routine ABA method applied at the Oxford Radiocarbon Accelerator Unit (ORAU) that includes an additional bleach treatment, and extraction of collagen. The C:N atomic weight ratio of the untreated and pretreated parchment fractions was observed to be a useful indicator of the presence or successful removal of contaminants. The pretreatment methods that produced the most accurate 14C dates and acceptable C:N ratios were found to be ABA protocols (without bleach) and collagen extraction; solvent washes and acid pretreatments alone were not sufficient to remove all contaminants and produce reliable 14C dates. The inclusion of a base wash did not affect the 14C dates of the samples, but did favorably influence the C:N ratio of the final product. © 2013 by the Arizona Board of Regents on behalf of the University of Arizona.
... The reason that the oil removal values calculated by Carmi (2002) on the basis of the 13 C measurements come out approximately similar to those he calculated from our 14 a results is that (as noted above) Carmi used, in effect, the same formula that we did, except that Carmi's was based on absolute percentages. Had we calculated the oil removal percentages based on the 13 C values using our formula we also would have come up with more or less the same results as those based on the 14 a results. ...
Carmi (2002) is a response to our study published inRadiocarbon 43(l) by Rasmussen et al. (2001). We noted widespread possible exposure to castor oil of the Dead Sea Scrolls (DSS) in the Rockefeller Museum in the 1950s and reported experiments showing that the AAA pretreatment used in the first 2 series of radiocarbon datings of the DSS (Bonani et al. [1992] and Jull et al. [1995]), "cannot be guaranteed to have removed all of the modem carbon in any samples if they had been contaminated with castor oil and hence could have produced some C-14 dates that were younger than the texts' true ages." Carmi, a coauthor of the Bonani et al. (1992) study, criticizes our analysis on 4 grounds: 1. Carmi argues that "the extant [radiocarbon] dates of the Dead Sea Scrolls do not suggest a major deviation from their palaeographic or specific ages. There is thus no indication that the pretreatment was inadequate." 2. Carmi claims that our study, Rasmussen et al. (2001), "miscalculated the efficiency of their AAA treatment from the C-14 data," and Carmi presents an alternative formula for calculation of the cleaning efficiency. 3. Carmi says the efficiency of the cleaning procedure of our experiments should have been calculated based on "the delta(13)C values of the samples," and that when this is done, a dramatically different result is obtained. 4. Carmi claims that our "strategy of testing the validity of the dates of the Dead Sea Scrolls is wrong." We believe that Carmi's response fundamentally misunderstands our paper and is in error on each of the 4 points.
A range of pretreatment methods was applied to 6 known-age historical parchments to investigate the most suitable methods for effectively removing contamination and ensuring accurate radiocarbon dates while minimizing unnecessary destruction of potentially valuable historical documents. The methods tested included an acid wash, different concentrations of acid-base-acid (ABA) pretreatments, the current routine ABA method applied at the Oxford Radiocarbon Accelerator Unit (ORAU) that includes an additional bleach treatment, and extraction of collagen. The C:N atomic weight ratio of the untreated and pretreated parchment fractions was observed to be a useful indicator of the presence or successful removal of contaminants. The pretreatment methods that produced the most accurate ¹⁴ C dates and acceptable C:N ratios were found to be ABA protocols (without bleach) and collagen extraction; solvent washes and acid pretreatments alone were not sufficient to remove all contaminants and produce reliable ¹⁴ C dates. The inclusion of a base wash did not affect the ¹⁴ C dates of the samples, but did favorably influence the C:N ratio of the final product.
Samples from Qumran dated by Radiocarbon are potentially contaminated with preservatives or other contaminants. Th is includes some of the Dead Sea Scrolls, which were treated with castor oil in the 1950s. This castor oil is not removed by the standard AAA pre-treatment used for 14C samples. We developed a pre-cleaning step, to be applied before the standard 14C procedure, which has shown to remove such contaminants effectively.
This paper finds a parallel to the division of each Babylonian zodiacal sign into 30 degrees in the Enochic cosmology. In particular a new explanation of the rare Aramaic word חרתיה in 4Q209 (4Q209 7iii 1-2, 6) from the Aramaic Astronomical Book is offered as describing heavenly openings on the horizon for the daily rising and setting of the sun. These openings were smaller parts of each one of the twelve gates compared previously by scholars to the zodiacal signs. It seems plausible that the description of the daily openings appeared four times in the account of every year at the end of each season. The addition of these four days can be seen as part of the author’s polemic against the Mesopotamian 360-day year. An implication of the repetition of the sentence in 4Q209 8 3-4 is that this scroll was probably longer than previously assumed and included a triennial cycle synchronizing lunar and solar years.
Thesis (Ph. D.)--University of Notre Dame, 2007. Thesis directed by James C. VanderKam for the Department of Theology. "July 2007." Electronic reproduction. Includes bibliographical references (leaves 315-334).
The name Dead Sea Scrolls refers to some 1200 manuscripts found in caves in the hills on the western shore of the Dead Sea during the last 45 yr. They range in size from small fragments to complete books from the holy scriptures (the Old Testament). The manuscripts also include uncanonized sectarian books, letters and commercial documents, wirtten on papyrus and parchment. In only a few cases, direct information on the date of writing was found in the scrolls. In all other cases, the dating is based on indirect archaeological and palaeographical evidence. To check this evidence, radiocarbon ages of 14 selected scrolls were determined using accelerator mass spectrometry. The calibrated radiocarbon ages agree well, except in one case, with the paleographic estimates or the specific dates noted on the scrolls. -Authors
We report on new 14C measurements of samples of 18 texts (scrolls) and 2 linen fragments from Qumran Caves 1, 2, and 4 and from Na al ever, both in the Dead Sea region. The radiocarbon results are in good agreement with estimates of age based on paleography.
We report on new 14 C measurements of samples of 18 texts (scrolls) and 2 linen fragments from Qumran Caves 1, 2, and 4 and from Nahal Hever, both in the Dead Sea region. The radiocarbon results are in good agreement with estimates of age based on paleography.
The name Dead Sea Scrolls refers to some 1200 manuscripts found in caves in the hills on the western shore of the Dead Sea during the last 45 years. They range in size from small fragments to complete books from the holy scriptures (the Old Testament). The manuscripts also include uncanonized sectarian books, letters and commercial documents, written on papyrus and parchment. In only a few cases, direct information on the date of writing was found in the scrolls. In all other cases, the dating is based on indirect archaeological and paleographical evidence. To check this evidence, radiocarbon ages of 14 selected scrolls were determined using accelerator mass spectrometry. The calibrated radiocarbon ages agree well, except in one case, with the paleographic estimates or the specific dates noted on the scrolls.
Some fragments of the Dead Sea Scroll manuscripts were contaminated with castor oil in the late 1950s. We have conducted experiments in order to establish if the AAA pretreatment cleaning procedures conducted on Dead Sea Scroll manuscript samples in the last two dating series (Bonani et al. 1992; Jull et al. 1995) were effective in removing oil contamination. Our experiments show that not all oil contamination can be expected to have been removed by the acid-alkaline-acid (AAA) pretreatment, and that the radiocarbon ages previously reported therefore cannot be guaranteed to be correct. Any samples contaminated with castor oil were most likely reported with ages that are too young by an unknown amount.
Some fragments of the Dead Sea Scroll manuscripts were contaminated with castor oil in the late 1950s. We have conducted experiments in order to establish if the AAA pretreatment cleaning procedures conducted on Dead Sea Scroll manuscript samples in the last two dating series were effective in removing oil contamination. Our experiments show that not all oil contamination can be expected to have been removed by the acid-alkaline-acid (AAA) pretreatment, and that the radiocarbon ages previously reported therefore cannot be guaranteed to be correct. Any samples contaminated with castor oil were most likely reported with ages that are too young by an unknown amount.