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Thermoluminescence and electron spin resonance dating of freshwater fossil shells from Pa Toh Roh Shelter archaeological site in southern Thailand · 10.1016/j.heliyon.2022.e10555

Name: Verified Rigor Record — Thermoluminescence and electron spin resonance dating of freshwater fossil shells from Pa Toh Roh Shelter archaeological site in southern Thailand · 10.1016/j.heliyon.2022.e10555
Item: Thermoluminescence and electron spin resonance dating of freshwater fossil shells from Pa Toh Roh Shelter archaeological site in southern Thailand · 10.1016/j.heliyon.2022.e10555
Rating: 60
Author: Αlpha¹

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Αlpha¹ Editorial

This rigor review was examined and confirmed by Αlpha¹ Editorial · July 6, 2026

Αlpha¹ Rigor Review

Rigor Reviewed

WARN

Warnings to address · Observational Study

Eight dimensions — click a segment for details

Critical

High-priority

Model-reported confidence: moderateReviewer agreement: moderateEngine: 7.6.0Source: full text

Not verified in this report

References were not verified against Crossref/OpenAlex.
No reported statistical tests were found to recompute.
No data or code availability links were detected to verify.

This Αlpha¹ Rigor Review uses AI Rigor Reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.

This paper presents TL and ESR dating of freshwater fossil shells, with a clear premise and adequate reporting transparency. However, the study design has gaps (only 2 of 6 samples cross-checked with ESR, no outlier handling described), the statistical presentation lacks error bar definitions and software versioning, and the data availability statement is wholly inadequate—it does not provide any concrete access route to the data. The unsupported claim that 'TL sensitivity is better than ESR by one order of magnitude' also needs addressing.

Three independent reviewers evaluated all eight dimensions; this synthesis reconciles their divergences (primarily on study design and statistical analysis) by weighing the detailed checklist evidence. Biological variables and ethical approvals were unanimously N/A. The statistics component (0 tests recomputed) is non-contributory.

12 major claims checked against the paper's own evidence: 2 not fully backed by the presented evidence (unsupported or overstated).

Rigor

Eight Dimensions2 pass · 3 fail

12 major claims2 unsupported3 partial7 supported

The introduction reviews prior dating efforts on shells and carbonates, identifies the lack of absolute dating at the site, and states the aim to resolve precision discrepancies between TL and ESR. Limitations such as the sensitivity of TL for quartz versus aragonite and the open-system behavior of fossil shells are discussed. The logic linking prior work to the study objectives is coherent.

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 80% conf

The scientific premise is established through citation of prior work and a logical rationale, but the paper does not explicitly address how limitations of prior research are mitigated.

Evidence

direct quote[Introduction, paragraphs 3-5]

“One of the earliest TL-dating works dedicated to Pecten shells was conducted to compare with the ESR result.”

direct quote[Introduction, paragraph 5]

“In this paper, we aim to measure a sample with TL compared to the ESR. This will answer the discrepancy between these two techniques, provided it will give us a guideline on how to use each type of measurement to determine the exact age of the material.”

absence[Introduction and Methods]

No explicit description of how limitations of prior research are addressed.

PASSReviewer 2· 90% conf

The paper clearly establishes the scientific premise by citing prior work on TL and ESR dating of shells, provides a logical rationale for comparing the two techniques, and identifies a gap to resolve discrepancies in precision.

Evidence

direct quote[Introduction]

“One of the earliest TL-dating works dedicated to Pecten shells was conducted to compare with the ESR result. It showed that they were all in agreement with each other.”

direct quote[Introduction]

absence[Introduction]

Limitations of prior research are not explicitly addressed.

PASSReviewer 3· 95% conf

The paper clearly establishes the scientific rationale for dating the fossil shells using TL and ESR, citing extensive prior work and acknowledging limitations of previous studies.

Evidence

direct quote[Introduction, paragraphs 5-7]

“There are a variety of absolute dating techniques that yield accurate dates for fossil shells, e.g., radiocarbon, electron spin resonance (ESR), thermoluminescence (TL), and optically stimulated luminescence (OSL) dating.”

direct quote[Introduction, paragraph 8]

direct quote[Discussion, paragraph 3]

“Because fossil shell behaves as an open system, the radioactive disequilibrium is exhibited... ages in this study were possibly underestimated.”

For an observational study with a bench measurement component, several sub-criteria are applicable (power_analysis, replicate_distinction, inclusion_exclusion, outlier_handling). None are reported adequately. Samples were collected from specific depths but no pre-defined criteria are given. Aliquots are used for dose-response curves but biological vs technical replicates are not distinguished. No sample size calculation or outlier handling is mentioned.

Sub-criteria

controlsN/A

power analysisNOT REPORTED

blinding levelsN/A

outlier handlingNOT REPORTED

randomization unitN/A

inclusion exclusionNOT REPORTED

randomization methodN/A

replicate distinctionINADEQUATE

independent replicationNOT REPORTED

Per reviewer (3) — the votes behind the verdict

FAILReviewer 1· 70% conf

The study design lacks many essential experimental rigor elements: no randomization, blinding, power analysis, inclusion/exclusion criteria, or outlier handling are reported. Replicate distinction is only partially described.

Evidence

paraphrase[Section 3.1, paragraph 1]

“Samples were collected from Levels 2-4 at an archaeological site, but no pre-defined criteria for inclusion or exclusion are provided.”

direct quote[Section 3.2, paragraph 2]

“Each sample was divided into 9 aliquots, approximately 300-500 mg each, and all the aliquots were irradiated for TL measurements.”

absence[Methods]

No power analysis or outlier handling reported.

N/AReviewer 2· 90% conf

The study design involves sample collection and measurement rather than an interventional or comparative experiment; none of the standard study design sub-criteria (randomization, blinding, power analysis, etc.) are applicable.

Evidence

paraphrase[Section 3.1 Sample collection]

“The paper states that samples were collected at Levels 2-4, with codes SH1-SH6 assigned.”

absence[Methods]

No randomization, blinding, power analysis, or control group is described.

WARNReviewer 3· 70% conf

The study design is appropriate for a geochronology analysis, but several standard rigor elements are not reported or are inadequately addressed, such as clear inclusion/exclusion criteria and explicit outlier handling.

Evidence

direct quote[Section 3.2, paragraph 2]

“Each sample was divided into 9 aliquots, approximately 300-500 mg each, and all the aliquots were irradiated for TL measurements. Then Each sample was divided into 10 aliquots, approximately 0.50 g each, and all the aliquots were irradiated for ESR measurements.”

direct quote[Section 4.4, paragraph 3]

“In this research, ESR techniques were applied to fossil shell samples SH1 and SH2 to compare these with TL techniques.”

absence[Methods, Section 3.2]

No explicit exclusion criteria or outlier handling is described.

The samples are ancient freshwater fossil shells. No living animals or human subjects are involved. The sub-criteria for biological variables (sex, age, health, species/strain, housing, demographics) do not apply to fossil materials.

Sub-criteria

demographicsN/A

sex reportedN/A

sex justifiedN/A

age weight healthN/A

housing conditionsN/A

species strain sourceN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 90% conf

The study uses fossil shells, not living organisms, so biological variables (sex, age, species, housing, demographics) are not applicable.

Evidence

direct quote[Title and Section 3.1]

“Thermoluminescence and electron spin resonance dating of freshwater fossil shells from Pa Toh Roh Shelter archaeological site”

N/AReviewer 2· 90% conf

The study uses fossil shells rather than living organisms or human subjects, so biological variables such as sex, age, strain, and housing conditions are not applicable.

Evidence

direct quote[Section 3.1 Sample collection]

“The samples consist of freshwater fossil shells and surrounding sediments that were collected by personnel of the 13th Regional Office of Fine Arts Department Songkhla”

N/AReviewer 3· 90% conf

The study uses fossil shells and sediment, not living organisms; therefore, biological variables such as sex, age, health, and housing conditions are irrelevant.

Evidence

direct quote[Abstract]

“six portions of freshwater fossil shells, used as samples, contain calcium carbonate polymorphs acquired from six locations in Pa Toh Roh Shelter archaeological site”

No human participants, animals, or identifiable data are involved. The shells are archaeological artifacts. There is no mention of ethics approval, which is appropriate for this type of materials analysis.

Sub-criteria

iacuc statementN/A

informed consentN/A

irb ethics statementN/A

regulatory complianceN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 95% conf

The study involves only archaeological fossil shells and does not involve human subjects, animals, or non-public subject-level data, so ethical approval is not required.

Evidence

absence[Entire paper]

No human or animal subjects are involved.

N/AReviewer 2· 90% conf

The study does not involve human subjects, animals, or non-public identifiable data; therefore ethical approvals and consent are not required.

Evidence

direct quote[Section 3.1 Sample collection]

“The samples consist of freshwater fossil shells and surrounding sediments that were collected by personnel of the 13th Regional Office of Fine Arts Department Songkhla at the archaeological site of Khao Han cave”

N/AReviewer 3· 95% conf

The study involves archaeological fossil shells and sediment, not human or animal subjects requiring ethical approval.

Evidence

absence[Entire paper]

No human or animal subjects are involved.

The paper mentions reagents (HCl, acetic acid) and instruments (Harshaw-3500 TL reader, Bruker ESR spectrometer) but provides no catalog numbers or RRIDs. The online calculator DRAC is referenced but no version is given. These are generic resources for a dating study; the dimension is set to not_applicable because no key biological/chemical resource (as defined in the rubric) is central to the study.

Sub-criteria

mycoplasma testingN/A

reagents identifiedN/A

organisms identifiedN/A

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 90% conf

The study uses standard laboratory chemicals and instruments (HCl, TL reader, ESR spectrometer) but no key biological resources (antibodies, cell lines, organisms) or unique reagents requiring RRID. The software used (DRAC) is mentioned but not fully identified.

Evidence

direct quote[Section 3.2]

“The samples were gently ground with a mortar, and the grains were sieved in order to obtain the fraction between 90-150 μm.”

paraphrase[Section 3.2, last paragraph]

“The online Dose Rate and Age Calculator (DRAC) is used without stating a version number.”

N/AReviewer 2· 80% conf

The study uses standard geological/archaeological techniques without proprietary biological reagents, cell lines, organisms, or bespoke software; thus no key biological or chemical resources are considered applicable.

Evidence

paraphrase[Methods]

“The study uses fossil shells, HCl, acetic acid, and standard instruments; no proprietary reagents or organisms are employed.”

PASSReviewer 3· 80% conf

Key instruments and reference software are identified, though catalog numbers and RRIDs are not provided. This is acceptable for the field.

Evidence

direct quote[Section 3.2, paragraph 3]

“The emitted TL was recorded using a Harshaw-3500 TL reader.”

direct quote[Section 3.2, paragraph 4]

“ESR measurements were performed at room temperature utilizing a pulsed ESR Bruker EMX premium spectrometer.”

direct quote[Section 3.2, paragraph 7]

“based on the online Dose Rate and Age Calculator (DRAC) using the conversion factors from G. Adamiec and M. J. Aitken”

The paper uses linear regression to fit dose-response curves but does not specify the type (ordinary least squares) or report any p-values from the regression. No normality or homoscedasticity checks are reported. Accumulated doses and ages are given with standard errors, but no effect sizes or confidence intervals for the primary outcomes. The software used (DRAC) is not versioned. The growth curve figures show individual data points, which is good, but error bars are not defined in the figure legends or text.

Sub-criteria

tests namedINADEQUATE

exact p valuesNOT REPORTED

effect sizes ciNOT REPORTED

data presentationINADEQUATE

software identifiedNOT REPORTED

assumptions verifiedNOT REPORTED

mathematical plausibilityN/A

Per reviewer (3) — the votes behind the verdict

FAILReviewer 1· 80% conf

Statistical reporting is incomplete: no tests are fully named (only 'linear regression' is mentioned), assumptions are not verified, exact p-values are not reported, effect sizes and confidence intervals are absent, software is not identified with version, and data presentation (error bars undefined) is inadequate.

Evidence

direct quote[Abstract and Section 4.2]

“Linear regression was used to fit the dependence of TL intensity on dose with a linear saturation function.”

absence[Results]

No exact p-values, effect sizes, or confidence intervals are reported.

paraphrase[Figure 7, 9 captions]

“Growth curves show data points with error bars, but the figure captions do not define what the error bars represent (SD, SEM, or CI).”

PASSReviewer 2· 85% conf

The statistical approach is appropriate for the study type: linear regression for dose-response curves and reporting of ages with uncertainties. Most sub-criteria are scored as adequate or not applicable.

Evidence

paraphrase[Section 4.2 and Figure 7]

“Figure 7 shows TL response vs dose with data points and fitted lines; the text states 9 aliquots per sample for TL.”

direct quote[Section 3.2]

“The concentrations of those radioactive elements are then used to estimate Din and Dex based on the online Dose Rate and Age Calculator (DRAC)”

WARNReviewer 3· 75% conf

Statistical methods are named and software is identified, but assumptions are not verified and error bars are not explicitly defined in figures.

Evidence

direct quote[Section 4.2, paragraph 2]

“A glow-curve deconvolution (GCD) for general orders of the kinetics is then employed to fit the curves based on those temperatures.”

direct quote[Section 3.2, paragraph 7]

“based on the online Dose Rate and Age Calculator (DRAC)”

absence[Figures 6, 7, 9]

Error bars in figures are not defined.

The paper states: 'This research is ongoing and not complete yet and therefore not to be disclosed unless being published elsewhere at the moment.' This is inadequate as it lacks a proper repository, platform, or conditions for access. No raw data are deposited, and no accession numbers are provided. Code sharing is not applicable. With none of the applicable sub-criteria adequate, the dimension fails.

Sub-criteria

code sharingN/A

accession numbersNOT REPORTED

repository depositNOT REPORTED

data availability statementINADEQUATE

Per reviewer (3) — the votes behind the verdict

FAILReviewer 1· 90% conf

The data availability statement is vague and does not provide a concrete access route; no data repository deposit, accession numbers, or code sharing are reported.

Evidence

direct quote[Declarations, Data availability statement]

“This research is ongoing and not complete yet and therefore not to be disclosed unless being published elsewhere at the moment.”

absence[Declarations]

No data repository deposit, accession numbers, or code sharing.

FAILReviewer 2· 95% conf

The data availability statement is vague and does not provide a concrete access route; no data are deposited in a repository, and no code is shared.

Evidence

direct quote[Declarations]

“Data availability statement This research is ongoing and not complete yet and therefore not to be disclosed unless being published elsewhere at the moment.”

absence[Declarations]

No repository deposit or accession numbers are provided.

FAILReviewer 3· 90% conf

A data availability statement is present but vague, and no data have been deposited in a repository; custom code is not shared.

Evidence

direct quote[Declarations section]

“This research is ongoing and not complete yet and therefore not to be disclosed unless being published elsewhere at the moment.”

absence[Entire paper]

No repository deposit or accession numbers.

The paper provides comprehensive descriptions of sample preparation, irradiation, TL and ESR measurements, and dose calculation. All six samples and their ages are reported. Limitations (radioactive disequilibrium, underestimation) are acknowledged. Conclusions are proportional to the data, noting that TL sensitivity is better but without overclaiming. Funding source (Prince of Songkla University) and conflict of interest are declared.

Sub-criteria

funding coiADEQUATE

trial registrationN/A

reporting guidelineN/A

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedADEQUATE

conclusions proportionalADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 85% conf

Reporting transparency is adequate overall: limitations are discussed, outcomes are reported, conclusions are proportional, and funding/COI are disclosed. Methods completeness is somewhat lacking in detail but still described.

Evidence

direct quote[Section 3.2]

“The grains were again etched in 0.5% acetic acid for a few minutes in order to suppress spurious TL emission”

direct quote[Discussion, paragraph 4]

“Because fossil shell behaves as an open system, the radioactive disequilibrium is exhibited... ages in this study were possibly underestimated.”

direct quote[Declarations]

“Tidarut Vichaidid was supported by Prince of Songkla University.”

PASSReviewer 2· 90% conf

Methods are sufficiently detailed for replication, all outcomes are reported, limitations are discussed, conclusions are proportional, and funding/conflicts are stated.

Evidence

paraphrase[Section 3.2 Preparation of specimens]

“The paper describes washing, etching, grinding, sieving, and irradiation steps in detail.”

direct quote[Section 4.4]

“Because fossil shell behaves as an open system, the radioactive disequilibrium is exhibited... ages in this study were possibly underestimated.”

direct quote[Declarations]

“Funding statement: Tidarut Vichaidid was supported by Prince of Songkla University. Declaration of interests statement: The authors declare no conflict of interest.”

PASSReviewer 3· 90% conf

Methods are described in sufficient detail for replication, limitations are discussed, conclusions are proportional, and funding/COI are reported.

Evidence

direct quote[Section 3.2]

“The freshwater shells were washed and cleaned in an ultrasonic bath, followed by etching in 5% HCl for 1 hour...The grains were sieved in order to obtain the fraction between 90-150 μm.”

direct quote[Section 4.4, paragraph 3]

“Because fossil shell behaves as an open system, the radioactive disequilibrium is exhibited...ages in this study were possibly underestimated.”

direct quote[Declarations section]

“Funding statement: Tidarut Vichaidid was supported by Prince of Songkla University. Declaration of interests statement: The authors declare no conflict of interest.”

22 copyedit issues flagged (6 major): mostly typo, clarity, grammar.

Αlpha¹ Rigor Action ItemsFinal pass before journal submission

The paper is published, not in submission. An informed reader should note that the data are not available for verification, the unsupported sensitivity claim weakens the conclusions, and the partial ESR cross-check limits the strength of the inter-technique comparison. These issues would warrant a correction or a clarifying comment from the authors, but do not invalidate the core age estimates.

1.
HIGHdata code
Replace the current vague data availability statement with a concrete one: deposit raw TL glow curves, ESR spectra, and NAA concentration data in a public repository (e.g., Zenodo, Mendeley Data) and provide the DOI or accession number in the Declarations section.
Without a concrete access route, the paper fails reproducibility standards and most journal data policies.
2.
HIGHrigor
Add the missing evidence for the claim 'TL sensitivity is better than ESR by one order of magnitude' in the Results section, or remove/qualify the claim in the Conclusion.
The claim audit shows this assertion is unsupported; an unsupported headline conclusion can mislead readers and invite post-publication critique.
3.
HIGHrigor
Define what the error bars represent (SD, SEM, or CI) in the captions of Figures 6, 7, and 9.
Undefined error bars make it impossible to interpret the precision and variability shown in the dose-response and growth curves.
4.
HIGHstatistics
Add a version number and URL for the DRAC online calculator (e.g., 'DRAC v1.2, https://www.aber.ac.uk/drac/') in Section 3.2.
Without a version, the calculation configuration cannot be reproduced or checked for updates that might alter results.
5.
HIGHrigor
Provide a rationale for why only two of the six shell samples (SH1 and SH2) were cross-checked with ESR, and discuss how this partial replication limits the comparison.
The independent_replication sub-criterion is currently inadequate; a clear justification helps readers assess the strength of the technique comparison.
6.
MEDIUMreporting
In Section 3.2, replace vague timing references (e.g., 'a few minutes') with specific durations (e.g., 'etched for exactly 2 minutes').
Precise timing is essential for replication of the specimen preparation protocol.
7.
MEDIUMreporting
Specify the software (if any) used for linear regression and GCD fitting (e.g., OriginPro, R, dedicated software) with version number.
Naming the analysis software and version supports reproducibility of the curve-fitting procedures.
8.
MEDIUMreporting
Acknowledge that age estimates may be affected by the aragonite-to-calcite transformation and discuss this as a limitation in Section 4.4.
The mineral phase transition is a known complication in shell TL dating; its absence from the limitations discussion is a gap.
9.
MEDIUMcopyedit
Fix the typo in Section 3.1: change 'achaeologically' to 'archaeologically' and correct subject-verb agreement ('there was nothing archaeologically interesting').
Typos and grammatical errors reduce professional presentation and may distract readers.
10.
MEDIUMcopyedit
In the Introduction, revise the sentence fragment starting 'Various items such as pottery...' to a complete sentence.
The incomplete sentence obscures the description of archaeological finds.
11.
MEDIUMcopyedit
In Section 5 (Conclusion), change 'asylum' to 'refuge' or 'shelter' to avoid an unusual word choice.
The term 'asylum' is an unusual and potentially confusing word for describing a campsite; 'refuge' is more standard.
12.
LOWcopyedit
Standardize the capitalization of 'thermoluminescence' (lowercase) throughout the manuscript.
Inconsistent capitalization of a key technical term appears unprofessional.
13.
LOWcopyedit
Add a comma after 'On the average' in Section 4.4 and rephrase the sentence for parallel structure.
Improves readability and grammatical correctness.
14.
LOWcopyedit
Remove the author name 'Vichaidid Tidarut' from the title line in the manuscript header.
The author name appears to be a formatting error in the title.
15.
LOWreporting
Add an explicit statement that no ethical approval was required because the study uses only archaeological specimens and no human subjects.
Even when N/A, an explicit statement enhances transparency.

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