The DOI matches its Crossref record; 15 of the 16 references it cites were found in a registry or an index; 7 of the 20 sources its claims cite were checked for support.
Radiocarbon Dating of “Old” Charcoal Using a Wet Oxidation, Stepped-Combustion Procedure
Open accessAbstract
We present results that validate a new wet oxidation, stepped-combustion procedure for dating “old” charcoal samples. An acid–base–wet oxidation (ABOX) pretreatment procedure has been developed that is used in place of the conventional acid-base-acid (ABA) pretreatment. Combustions and graphitizations are performed in a vacuum line that is insulated from the atmosphere by a second backing vacuum to eliminate the risk of atmospheric leakage into the line at any stage of the procedure. Combustions are performed at 3 temperatures (330 °, 630 ° and 850 °) with a graphite target produced from the CO2 evolved during each combustion step. In this way, the removal of any contamination can be monitored, and a high degree of confidence can be placed on the final age. The pretreatment, combustion, graphitization, and measurement blank for the procedure, based on the analysis of a “radiocarbon-dead” graphite, is 0.5 ± 0.5 μg C (1σ, n=14), equivalent to 0.04 ± 0.02 pMC or an “age” of approximately 60 ka for a 1 mg graphite target. Analyses of a “radiocarbon-dead” natural charcoal after ABOX pretreatment and stepped combustion suggest that the total blank (including contamination not removed by pretreatment) may be higher than for graphite, ranging up to 0.10 ± 0.02 pMC. Additional experiments confirm good agreement with accepted values for the international low-14C “New Kauri” standard (0.16–0.25 pMC). They also confirm excellent reproducibility, with 3 separate dates on different aliquots of a charcoal sample from Ngarrabullgan Cave (Queensland, Australia) ranging from 35.2 to 35.5 ka 14C BP. It is also demonstrated that the ABOX pretreatment, in conjunction with the new vacuum line described here, is able to remove contamination not removed by the conventional ABA pretreatment, suggesting that the technique can be used to produce reliable 14C dates on charcoal up to at least 50 ka.
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Claims the paper makes
7 of 20 cited sources checked · 1 supported · 1 flagged · accuracy not yet measured
At least one cited source doesn’t support this claim or points to a different paper, and none confirmed it — see the verdicts below.
In the paper
“Previous studies have demonstrated that the major source of introduced contamination in the com- bustion of samples for 14C analysis comes from the copper oxide used during combustion (Vogel et al. 1987;Vandeputte et al. 1998).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > CONCLUSION
What the sources say
- Disputedcites Vogel et al. 1987 sourceExperimental — accuracy not yet measured
In “Contamination During Combustion” (page not provided), replacing copper oxide with ultra-pure oxygen produced indistinguishable results, and changing the amount of copper oxide did not change measured ¹⁴C. The paper instead identifies the Vycor combustion tube as the likely source and reports lower background when Pyrex tubes were used. (LLM, conf=0.90)
Checked by a reasoning model — may be wrong.
- Not matchedcites Vandeputte et al. 1998
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Disputed
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“However, in some cases it has been demonstrated that the ABA pretreatment does not remove all contaminants (e.g.Gillespie et al. 1992; Gillespie 1.997)”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
What the sources say
- Supportedcites Gillespie et al. 1992 source
The Conclusions state that the commonly used acid/base/acid pretreatment did not yield acceptable dates for the Graham’s Terrace sediments. They explain that younger contaminants, particularly humic materials, resisted standard pretreatment in these fine-grained sediments. This supports the citing sentence’s qualifier, “in some cases.” (LLM, conf=0.94)
- Not matchedcites Gillespie 1.997
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Load-bearingStrength:boosted· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Work by Cachier et al. (1989) has shown that this treatment will remove organic contaminants with minimal removal of black carbon from aerosol samples.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Combustion
What the sources say
- Partly supportedcites Cachier et al. (1989) sourceExperimental — accuracy not yet measured
Section 3.4 says precombustion removes organic matter while seeking to minimize soot-carbon loss. It specifies 340 °C for two hours—not 330 °C—and estimates a 24% loss of refractory carbon under those conditions, so the claim’s temperature and unqualified description of minimal loss are not supported. (LLM, conf=0.86)
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Partly supported
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It is also demonstrated that the ABOX pretreatment, in conjunction with the new vacuum line described here, is able to remove contamination not removed by the conventional ABA pretreatment”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Analyses of a”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesThe paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“For the samples that were subjected only to an acid-base pretreatment, it is evident that minor contamination is introduced to the sample during these initial steps, most likely from adsorption of atmospheric CO2 by the alkaline solution.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
- The authors state this as an assumption: The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“All 5 samples show a significant shift to older ages from the 330 °C to 630 °C step (Table 1 and Fig- ure 6).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
- The authors state this as an assumption: The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The weighted mean 14C age (equivalent to the age that would have been obtained from complete combustion) of the untreated and ABA pretreated samples for all combustion steps (41.6 and 46.3 ka) are significantly younger at the 26 level than the cone- sponding weighted mean age for the ABOX pretreated sample (51.3 ka).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The values obtained from these 4 samples are statistically indistinguishable from the 10 samples that were not subjected to any pre- treatment prior to combustion.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“A sample previously analyzed from this deposit subjected to the ABOX pretreatment (without stepped combustion) also returned an age at the upper extreme of the dated sample population (OZC-733, 35.5 ± 0.6 ka; Roberts et al. 1994)”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
What the sources say
- Not checked — no full text of the sourcecites Roberts et al. 1994 source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
- The authors state this as an assumption: The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
- It may state two separate claims as one. 29
- The quote only partly states this claim. 1
- Probably not a substantial claim. 21
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“This blank is at least an order of magnitude lower than the 0.7% modern carbon that would be equivalent to an age of 40 ka, and is 2-10 times lower than commonly reported procedural blanks (Kitagawa et al. 1993;Vogel et al. 1987;Gagnon and Jones 1993).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
What the sources say
- Partly supportedcites Kitagawa et al. 1993 sourceExperimental — accuracy not yet measured
The “14C Background (or Blank) Levels” section (page not provided) reports a procedural background of 0.112 ± 0.057 percent modern carbon, so the paper supplies an example of a blank for comparison. It measures targets made from Yubari Mine coal, not a Ceylon graphite blank, and does not establish either the claimed order-of-magnitude difference from 0.7% or the 2–10-fold comparison. (LLM, conf=0.85)
- Partly supportedcites Vogel et al. 1987 sourceExperimental — accuracy not yet measured
The Contamination During Graphitization section reports anthracite backgrounds of 0.59 ± 0.24% modern, reduced to 0.44 ± 0.13% modern, providing a procedural-background comparison. It does not state the citing paper’s blank value, the 2–10-fold comparison, or that 0.7% modern is equivalent to 40 ka. (LLM, conf=0.82)
- Partly supportedcites Gagnon and Jones 1993 sourceExperimental — accuracy not yet measured
The Results report procedural blank values of 0.256% modern carbon for carbonate and 0.762% for organic carbon; the Conclusions equate the latter with about 39 ka, close to the cited 0.7% and 40 ka benchmark. The paper does not report a Ceylon graphite blank or establish that it is an order of magnitude below 0.7% modern carbon or 2–10 times below those procedural blanks. (LLM, conf=0.86)
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“the results for this standard, which range from 0.16 ± 0.06 pMC to 0.25 ± 0.06 pMC (48-51.7 ka), are internally consistent and comparable within error to the accepted range of values for this standard (0.12-0.21 pMC; Hogg et al. 1995).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
What the sources say
- Partly supportedcites Hogg et al. 1995 sourceExperimental — accuracy not yet measured
The Laboratory Analysis section gives the same 0.12–0.21 pMC range for the new kauri standard, but proposes applying it provisionally until unresolved measurement problems are addressed; it does not call it an accepted range. The cited paper does not report the citing authors’ 0.16–0.25 pMC results, which are presented as their own findings. (LLM, conf=0.86)
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Partly supported
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Additional experiments confirm good agreement with accepted values for the international low-14C”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesThe quote only partly states this claim.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The pretreatment, combustion, graphitization, and measurement blank for the procedure, based on the analysis of a”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“They also confirm excellent reproducibility, with 3 separate dates on different aliquots of a charcoal sample from Ngarrabullgan Cave (Queen- sland, Australia) ranging from 35.2 to 35.5 ka 14C BP.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For ABOX-pretreated samples, the results indicate that consistent, reproducible ages can be obtained from the 850 °C fraction, and possibly from the 630 °C fraction, but not from the 330 °C fraction (Figure 6).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- The authors state this as an assumption: The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
- The authors state this as an assumption: The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It should also be noted that calculated blanks in excess of 1 µg were from the first 2 Ceylon graphites prepared using the combustion line, and calculated blanks for all subsequent analyses have been consistently lower.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The ABOX pretreatment alone does not remove all contamination, as the lower temperature fractions of the step-combusted ABOX pretreated sample have younger 14C ages ( 37.7 and 51.3 ka) than the 850 °C fraction (55.9 ka).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“No ABA-treated sample was ana- lyzed, as the results from the untreated and ABOX-treated samples indicate that the Ngarrabullgan sample is virtually uncontaminated.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- The authors state this as an assumption: The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
- The authors state this as an assumption: The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Neither the stepped combustion of an unpretreated sample nor an ABA pretreatment with stepped combustion is sufficient to remove all contaminants.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The samples spanned a range of graphite weights from 0.1 to 2.2 mg, and the corresponding amount of modern carbon that would account for the observed pMC varies between about 0.1 and 1.7 µg, giving an average of approximately 0.5 ± 0.5 µg (16, n=14, equivalent to -60 ka for a 1 mg graphite target).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The resulting 14C ages of 60.7 and 62.4 ka BP (0.05 and 0.04 pMC, respectively) are statistically indistinguishable”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“All 14 measurements are consistent with the mean value of 0.04 pMC (x2v =1.2) and the stan- dard deviation of the data set is 0.02 pMC (Figure 3).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the case of untreated graphite, very little CO2 was produced in the 330 °C or 630 °C combustion steps, so the 3 targets were made from 3 combustions at 850 °C (850 I, II, III; Table 1).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Combustion
Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The precombustion of the Fe powder does not appear to affect its catalytic action during the conversion of CO2 to graphite.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Graphitization
Strength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✗ Based: failsProbably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Combustions are performed at 3 temperatures (330 °C, 630 °C and 850 °C) with a graphite target produced from the CO2 evolved during each combustion step.In this way, the removal of any contamination can be monitored, and a high degree of confidence can be placed on the final age.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Combustions and graphitizations are performed in a vacuum line that is insu- lated from the atmosphere by a second backing vacuum to eliminate the risk of atmospheric leakage into the line at any stage of the procedure.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Abstract
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✗ Based: failsProbably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“The proportion of OREC left after oxidation for 72 h depends on the nature of the charcoal and can range widely from 20 to 80%.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Pretreatment
What the sources say
- Not checked — no full text of the sourcecites Bird and Grocke (1997) source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This sample represents a worst case in that it is overlain by a vegetated soil profile and has been exposed to infiltrating waters and the organic compounds carried by those waters since deposition of the sediments and subsequent pedogenesis.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“A substantial body of dates have been published for this unit, with 19 14C determinations spanning 28.8-34.614Cka BP (David et al. 1997).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Samples
What the sources say
- Not checked — no full text of the sourcecites David et al. 1997 source
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“An additional step used in our procedure is a preoxidation of approximately 0.5 to 1.0 mg iron pow- der (Merck; 10 µm) to remove carbonaceous contaminants present in the Fe powder, or introduced during the sample loading procedure.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Graphitization
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“whereas the advent of luminescence techniques in the 1980s suggested that humans may have arrived at 54-60 ka BP (the”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
What the sources say
- Not checked — no full text of the sourcecites Roberts et al. 1994 source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“which has been substantially protected from interaction with infiltrating waters (discussed below).”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✗ Based: failsProbably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The stepped combustion removes contaminants present in the copper oxide and/or introduced during sample loading, and also removes contamination from samples not removed by the ABOX pretreatment.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > CONCLUSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“and the removal of all contamination must be verifiable.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✗ Checkable: fails✓ Load-bearing: passes✗ Based: failsProbably not a substantial claim. It may be too vague to check against evidence. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It therefore seems that although total combustion can produce reliable ages on charcoal, the effective limit of the 14C technique will be considerably younger for samples that are analyzed by total combustion.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“suggesting that the few '4C atoms observed may already be present in the Ceylon graphite itself or were possibly added during target pressing.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Strength:hedged· not yet calibratedCausal:conditional· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Detecting sample contamination and verifying the reliability of the ages produced also become more difficult as the age of the sample increases.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The other procedures used in this study, including preoxidation of the iron powder, use of molecular sieves, storage of samples in vacuo and the use of a vacuum-backed extraction line, may also con- tribute to overall blank reduction, but more importantly, guard against random contamination of individual samples.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > CONCLUSION
Strength:hedged· not yet calibratedCausal:conditional· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The completeness of the graphitization for the 850 °C (C) fraction can then be checked by measuring the total pressure, and CO2 pressure at the end of the reaction period.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Graphitization
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The so-called”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✗ Based: failsProbably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Significant contamination of samples from atmospheric leakage into the extraction line can poten- tially occur during the combustion of the sample to C02, or during graphitization.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Combustion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✗ Based: failsProbably not a substantial claim. The paper may give no reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Early 14C determinations suggested that humans first arrived about 40 ka BP (the”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
What the sources say
- Not checked — no full text of the sourcecites Allen and Holdaway 1995 source
- Not matchedcites O'Connell and Allen 1998
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“A graphite target is generally made from the CO2 produced during each combustion step (i.e., 330 °C, 630 °C, and 850 °C).In this way it is expected that any contaminants remaining after the sample pretreatment will be combusted in the 330 °C step, and that the reliability of the 14C age can be assessed by the coherence of the results from the 630 °C and 850 °C steps.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Combustion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Rests on an assumption: Oxidation removes less resistant phases first, working progressively from the outside to the interior of the particles.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The unit is thought to have undergone pedogenesis during a period of climatic stability similar to the present, and is likely to be at least of last interglacial age.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Samples
Strength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In practice this means that many laboratories will only quote 14C ages to about 40 ka BP (thousands of '4C years Before Present), with ages greater than this generally considered to be”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“All pretreatment steps are carried out in either a laminated flow cabinet, a HEPA-filtered clean lab, or capped vials, with all vessels and implements precleaned either by combustion overnight at 550 °C (Pyrex®) or 850 °C (quartz), or by washing with a hot solution of O.1 M K2Cr2O7 in a 2M solution of H2SO4.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Pretreatment
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, in the case of the AB-treated samples, there is a suggestion that the ages become younger for the 850 °C fraction, possibly owing to formation of Na2CO3, which has a decarbonation temperature of 851 °C.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > RESULTS AND DISCUSSION
Strength:hedged· not yet calibratedCausal:conditional· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
- The authors state this as an assumption: The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
- The authors state this as an assumption: The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The production of reliable 14C dates on old archaeological charcoal samples can assist in this respect.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Resolution of this discrepancy is important for a refined understanding of early human migration and colonization of the continent as well as of the ecological effects accompanying human colonization.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✗ Checkable: fails✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may be too vague to check against evidence.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The buried paleosol has been subject to infiltrating waters carrying organic compounds from the vegetated surface.Interactions between the charcoal and groundwater are evidenced by fine gypsum crystals deposited on the surface of some fragments.”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > Samples
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“In addition, the ages must be reproducible within the stated error bounds”
§ RADIOCARBON DATING OF "OLD" CHARCOAL USING A WET OXIDATION, STEPPED-COMBUSTION PROCEDURE > INTRODUCTION
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✗ Based: failsProbably not a substantial claim. The paper may give no reason why it holds.
The paper relies on this without support.
Oxidation removes less resistant phases first, working progressively from the outside to the interior of the particles.
“This is because oxi- dation can be expected to remove less resistant phases first, and work progressively from the outside to the interior of the particles.”
The authors state this as an assumption.
For a 14C date to be considered reliable at 50 ka, the combined blank from natural contamination and laboratory handling should be equivalent to a 14C age of at least 55 ka.
“We believe that for a 14C date to be considered reliable at 50 ka, for example, the combined blank from natural contamination and laboratory handling should be equivalent to a 14C age of at least 55 ka.”
The paper relies on this without support.
The 330 °C combustion step removes contaminants introduced during loading or adsorbed onto the sample surface.
“This step serves to remove contaminants that may have been introduced during the loading procedure or that are adsorbed onto the sample surface.”
The authors state this as an assumption.
The delta 13C values for ANU sucrose and charcoal are -11 per mil and -25 per mil, respectively, and a fractionation correction of 14 per mil (equivalent to 110 years) applies to each charcoal sample.
“Although the 613C value has not been mea- sured, it has been assumed that ANU sucrose and charcoal have values of -11%o and -25%, respec- tively, and hence a fractionation correction of 14% (equivalent to 110 yr) has been applied to each of the charcoal samples.”
The authors state this as an assumption.
The true blank for natural charcoal lies between the average value for the ABOX pretreated 850 degrees C fraction of Black Mountain charcoal and the Ceylon graphite blank (0.07 ± 0.05 pMC).
“A conservative approach to assigning a blank value to analyses of natural charcoals would be to assume that the true blank lies between the average value obtained for the ABOX pre- treated 850 °C fraction of the Black Mountain charcoal and the blank obtained for the Ceylon graph- ite (i.e., 0.07 ± 0.05 pMC).”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The check wasn’t confident either way, so it gives no verdict — never disputed.
In the citing paper
“Sedimentology analysis and reconstruction of sedimentation conditions of the Tonto Group [Grand Canyon] reveals that deposits of different stratigraphic sub-divisions were formed simultaneously in different litho-dynamical zones of the Cambrian paleobasin.”
From The Search for Solutions to Mysterious Anomalies in the Geologic Column (2019) · cites this paper as [34]
Experimental — accuracy not yet measuredThe check wasn’t confident either way, so it gives no verdict — never disputed.
In the citing paper
“[34] showed that sediments formed simultaneously by size and density in moving waters spontaneously in the disastrous Bijou Flood in Colorado of 1965.”
From The Search for Solutions to Mysterious Anomalies in the Geologic Column (2019) · cites this paper as [34]
Experimental — accuracy not yet measured
Citations
Cites
Performance of catalytically condensed carbon for use in accelerator mass spectrometry
Vogel, J. S., Southon, J. R., Nelson, D. E., & Brown, T. A. (1984) · Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms · doi:10.1016/0168-583x(84)90529-9 · Cited by 695
Determination of atmospheric soot carbon with a simple thermal method
Cachier, H., Bremond, M.-P., & Buat-Ménard, P. (1989) · Tellus B: Chemical and Physical Meteorology · doi:10.3402/tellusb.v41i3.15095 · Cited by 339
Roberts, R. G., Jones, R., Spooner, N. A., Head, M. J., Murray, A. S., & Smith, M. A. (1994) · Quaternary Science Reviews · doi:10.1016/0277-3791(94)90080-9 · Cited by 330
14C Background Levels in An Accelerator Mass Spectrometry System
Vogel, J. S., Nelson, D. E., & Southon, J. R. (1987) · Radiocarbon · doi:10.1017/s0033822200043733 · Cited by 286
A Batch Preparation Method for Graphite Targets With Low Background for AMS 14C Measurements
Kitagawa, H., Masuzawa, T., Makamura, T., & Matsumoto, E. (1993) · Radiocarbon · doi:10.1017/s0033822200064973 · Cited by 260
Determination of the abundance and carbon isotope composition of elemental carbon in sediments
Bird, M. I., & Gröcke, D. R. (1997) · Geochimica et Cosmochimica Acta · doi:10.1016/s0016-7037(97)00157-9 · Cited by 193
Self-citationBeyond the radiocarbon limit in Australian archaeology and Quaternary research
Chappell, J., Head, J., & Magee, J. (1996) · Antiquity · doi:10.1017/s0003598x00083708 · Cited by 90
Burnt and Unburnt Carbon: Dating Charcoal and Burnt Bone from the Willandra Lakes, Australia
Gillespie, R. (1997) · Radiocarbon · doi:10.1017/s0033822200053236 · Cited by 69
The contamination of Pleistocene radiocarbon determinations in Australia
Allen, J., & Holdaway, S. (1995) · Antiquity · doi:10.1017/s0003598x00064334 · Cited by 60
David, B., Roberts, R., Tuniz, C., Jones, R., & Head, J. (1997) · Antiquity · doi:10.1017/s0003598x00084672 · Cited by 54
Self-citation
Flagged first, then by citations
1 of the 16 references couldn’t be matched to a known paper.
Research works printed but not linked: 1
- Mull, 1998, The effect of NOx and CO on the rate of transition metal oxide catalysed black carbon oxidation – an exploratory study, Applied Catalysis B – Environmental, 17
Cited by
Sorted by citations
Items 301–316 of 316
Jull, A. J. T., & Burr, G. S. (2014) · Springer eBooks · doi:10.1007/978-94-007-6326-5_101-1
Blockley, S. P. E. (2019) · Cambridge University Press eBooks · doi:10.1017/9781139013826.018 · Cited by 1
TREE RING RECONSTRUCTION OF MODERN RADIOCARBON DIOXIDE VARIABILITY OVER THE SOUTHERN OCEAN
Corran, R. (2021) · Open Access Victoria University of Wellington | Te Herenga Waka (Figshare) · doi:10.26686/wgtn.14703831.v1
50 years of radiocarbon dating in Australian archaeology
Wood, R. E. (2024) · Australian Archaeology · doi:10.1080/03122417.2024.2317591
“We now know that this was caused by tiny amounts of young carbon contamination, but it was not until 1999 that a new method was developed which could effectively clean charcoal (Bird et al. 1999).”
MethodBird, M. I. (2013) · Elsevier eBooks · doi:10.1016/b978-0-323-99931-1.00287-7
Self-citationHuman Presence in the Southeastern Tibetan Plateau after the Last Glacial MaximumPreprint
Wang, J., Tan, P.-Y., Feng, Y. X., et al. (2024) · SSRN Electronic Journal · doi:10.2139/ssrn.5071228
Encyclopedia of earth science research
Sato, F., & Nakamura, S. (2012) · Nova Science Publishers eBooks
New chronological data for the Middle Paleolithic hominin occupations at Anghilak Cave, Uzbekistan
Nishiaki, Y. A., Aripdjanov, O., Glantz, M. M., Tamura, T., Kitagawa, H., Arai, S., Ritzman, T. B., & Suleymanov, R. (2025) · Quaternary International · doi:10.1016/j.quaint.2025.110096 · Cited by 1
Marín-Arroyo, A. B., Torres-Iglesias, L., Duarte, E., Pérez, L. A., & de la Rasilla, M. (2026) · Radiocarbon · doi:10.1017/rdc.2025.10161
“These samples were treated before ABOx-SC procedures (Bird et al. 1999).”
Extrem-Membrado, V., Tortosa, J. E. A., Pardo-Gordó, S., et al. (2026) · Radiocarbon · doi:10.1017/rdc.2025.10183
“The application of sample pretreatment protocols and ultrafiltration methods help to improve the accuracy of the samples (Bird et al. 1999; Bowman 1990; Higham et al. 2006).”
Christopoulou, A., Karadimas, N., Özarslan, Y., & Ważny, T. (2026) · Dendrochronologia · doi:10.1016/j.dendro.2026.126500
Hilbert, Y. H., Geiling, J. M., Russo, G., et al. (2026) · Journal of Archaeological Science Reports · doi:10.1016/j.jasrep.2026.105728
The Age and Origin of Block Deposits in the Victorian Alps, Australia
Barrows, T. T., Worland, M. S., Murton, J., et al. (2026) · Permafrost and Periglacial Processes · doi:10.1002/ppp.70039
Self-citationTortosa, J. E. A., Conesa, M. V., Pérez, L., Álvarez, M. B., Maestro, A., Extrem-Membrado, V., Balcázar-Campos, N., Vidal-Matutano, P., Pardo, J. F. J., Piqueras, L., et al. (2026) · Quaternary Science Reviews · doi:10.1016/j.quascirev.2026.110041 · Cited by 1
Metadata
- Authors
- Bird, M. I., Ayliffe, L. K., Fifield, L. K., Turney, C. S. M., Cresswell, R. G., Barrows, T. T., & David, B.
- Affiliations
- Australian National University (AU)
- Venue
- Radiocarbon
- Publisher
- Cambridge University Press (CUP)
- Published
- 1999
- Volume
- 41
- Issue
- 2
- Pages
- 127-140
- ISSN
- 0033-8222 (ISSN-L)
- 1945-5755
- OpenAlex
- W1955935479
- Semantic Scholar
- 0b86b4d2ded1bc772aa8185d1d86f9fc14c36f78
- Cited by
- 315
- References
- 16
- Citations by year
- 2026: 7 · 2025: 9 · 2024: 7 · 2023: 8 · 2022: 5 · 2021: 9 · 2020: 15 · 2019: 15 · 2018: 19 · 2017: 17 · 2016: 17 · 2015: 14 · 2014: 19 · 2013: 15 · 2012: 14
- FWCI
- 41.83
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Radiocarbon (publishedVersion)
- UA Campus Repository (The University of Arizona) (acceptedVersion)
- Funders
- Australian Research Council
- Topics
- Social Sciences › Archeology › Archaeology and ancient environmental studies
- Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Geology and Paleoclimatology Research
- Physical Sciences › Earth and Planetary Sciences › Geochemistry and Petrology › Geological and Geochemical Analysis
- Keywords
- charcoal dating, graphitization, pollutant removal
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-09-27, under version 3 of the claim definition (prompt extract-v3).
A second model labelled each claim on 2026-09-27 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Cited sources are checked with a language model’s help (gpt-6-sol).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
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