The literature

This page exists so that nobody has to take the rest of the article on trust.  Every source it rests on is listed here with what it actually measured, who wrote it, and which way it cuts.

A catalogue of the literature bearing on ²³⁸U–²³⁴U–²³⁰Th and ²³⁵U–²³¹Pa dating of carbonates: the decay constants, the closed-system assumptions, the cross-checks against radiocarbon, layer counting and orbital forcing, the documented failures of the method, and the young-earth response to all of it.

It is deliberately not a reading list of things that agree with this site.  Several of the strongest entries here are mainstream papers that concede a problem in their own method, and at least one young-earth source is tagged undercuts because what it actually says weakens the young-earth case.

How to read an entry

Measurement or model.  A measured ²³⁰Th/²³⁸U activity ratio on a named coral fragment is an observation.  An "open-system corrected age" is the output of a three-parameter model that assumes a particular mechanism of uranium gain and loss, and it inherits every assumption in that model.  Both are useful.  They are not the same kind of thing.

The access route.  Recorded for every entry, because a large fraction of this literature sits behind paywalls and the route that worked is worth more to the next reader than the citation.  Where only a publisher abstract was obtained, the entry says so and no claim in the article rests on anything beyond that abstract.

Direction.  Whether the source supports, undercuts, or complicates the young-earth argument.  Assigned by what the source shows, not by what its authors believe.

Camp.  Mainstream, creationist, old-earth Christian, counter-apologetics, or unaffiliated.  Disclosure, not a verdict.

Field definitions

Decay constants and the physics of the method

Improvements in ²³⁰Th dating, ²³⁰Th and ²³⁴U half-life values, and U–Th isotopic measurements by MC-ICP-MS

Cheng, H., R. L. Edwards, C.-C. Shen, V. J. Polyak, Y. Asmerom, J. Woodhead, J. Hellstrom, Y. Wang, X. Kong, C. Spötl, X. Wang and E. C. Alexander Jr.  Earth and Planetary Science Letters 371–372 (2013): 82–91.  https://doi.org/10.1016/j.epsl.2013.04.006

topic: decay-constants camp: mainstream type: measurement access: abstract-only direction: background

The primary source for the half-lives every modern U-Th age uses.  Full text NOT obtained — ScienceDirect paywalled, no open-access copy in OpenAlex, Semantic Scholar, Unpaywall, CORE or Wayback.  The complete numeric abstract was obtained verbatim, as bytes, from the Karst Information Portal mirror at digitalcommons.usf.edu/kip_articles/2656/, and it carries every number the article needs.

Key figures, verbatim from that abstract: measured atomic ratios in calcite judged to be in secular equilibrium, ²³⁴U/²³⁸U = 54.970 (±0.019) × 10⁻⁶ and ²³⁰Th/²³⁸U = 16.916 (±0.018) × 10⁻⁶, "identical within errors"; half-lives 245,620 ± 260 a for ²³⁴U and 75,584 ± 110 a for ²³⁰Th (2σ).  Because systematic terms cancel when a ²³⁰Th age is computed, the effective uncertainties for dating are ±70 a on the ²³⁴U half-life and ±30 a on the ²³⁰Th half-life.  Resulting 2σ age uncertainty under ideal conditions: "±10 a at 10 ka, ±100 a at 130 ka, ±300 a at 200 ka, ±1 ka at 300 ka, ±2 ka at 400 ka, ±6 ka at 500 ka, and ±12 ka at 600 ka."

Note the structure of the argument: the half-lives are derived from carbonates assumed to be in secular equilibrium.  That assumption is tested, not merely asserted — see Hu et al. 2025 below — but it is an assumption, and an honest article should say so.

Sub-epsilon natural ²³⁴U/²³⁸U measurements refine the ²³⁴U half-life and U-Th geochronology

Hu, H.-M., C.-C. Shen, H. Cheng, J. D. Woodhead, R. L. Edwards, J.-X. Zhao, C.-Y. Huang, P.-Y. Lu, W.-Y. Chien, J. Wang, X. Jia, Y. Yokoyama, Y. Cai and J. Zachariáš.  Science Advances 11 (2025).  https://doi.org/10.1126/sciadv.adu8117

topic: decay-constants camp: mainstream type: measurement access: OA direction: undercuts

Obtained in full as JATS XML from Europe PMC (PMC12487893) and detagged locally.  CC-BY-NC.

Reproducibility of ±0.08 ‰ (2σ) on ²³⁴U/²³⁸U, and a recalibrated λ₂₃₄ = 2.82147 ± 0.00254 × 10⁻⁶ yr⁻¹, "corresponding to a half-life of 245,670 ± 260 years."  That "aligns with an independent determination of 244,900 ± 1340 years… that did not rely on secular equilibrium samples and matches the estimate of 245,620 ± 260 years by Cheng et al."  Age uncertainties fall to ±3 kyr at 600 ka and ±6 kyr at 700 ka.

The entry that matters most for the young-earth question is the equilibrium check.  Three Nullarbor Plain stalagmites — MO-1, 1536-05 and 2200-7, independently U-Pb dated to 3.83 ± 0.11, 3.76 ± 0.13 and 3.45 ± 0.18 Ma — plus a 266 Ma hydrothermal calcite vein from the Bohemian Massif, all measure δ²³⁴U indistinguishable from zero (MO-1 subsamples: +0.06 ± 0.09, +0.06 ± 0.10, −0.03 ± 0.12 ‰).  Four carbonates from three continents sit at secular equilibrium to one part in ten thousand.  Any differential change in the ²³⁸U and ²³⁴U decay rates would have left a measurable δ²³⁴U offset (see the calculation in research/chain-equilibrium.ts).

The paper also concedes a real weakness of the field, in print: "geological samples are frequently disturbed by environmental and climatic influences that prevent them from reaching and maintaining true secular equilibrium… Many laboratories now rely upon internally characterized standards, often assumed but not conclusively demonstrated to be in secular equilibrium.  This practice can inadvertently introduce systematic isotopic offsets, potentially biasing U-Th age determinations."

Precision measurement of half-lives and specific activities of ²³⁵U and ²³⁸U

Jaffey, A. H., K. F. Flynn, L. E. Glendenin, W. C. Bentley and A. M. Essling.  Physical Review C 4 (1971): 1889–1906.

topic: decay-constants camp: mainstream type: measurement access: paywalled direction: background

Already in sources/index.tsv (key jaffey-1971, file = -).  Supplies the ²³⁸U and ²³⁵U half-lives that anchor both chains.  Not re-obtained for this article.

The internal cross-check: two chains on one sample

Protactinium-231 dating of carbonates by thermal ionization mass spectrometry: implications for Quaternary climate change

Edwards, R. L., H. Cheng, M. T. Murrell and S. J. Goldstein.  Science 276 (1997): 782–786.  https://doi.org/10.1126/science.276.5313.782

topic: concordance-pa-th camp: mainstream type: measurement access: abstract-only direction: undercuts

Full text NOT obtained — science.org paywalled to the registered-reader account, no repository copy.  Publisher abstract obtained verbatim as raw text from NCBI E-utilities (PMID 9115200).

Verbatim: "Measurement of protactinium-231 (²³¹Pa) in carbonates by thermal ionization mass spectroscopy yields ²³¹Pa ages that are more than 10 times more precise than those determined by decay counting.  Carbonates between 10 and 250,000 years old can now be dated with ²³¹Pa methods.  Barbados corals that have identical ²³¹Pa and thorium-230 (²³⁰Th) ages indicate that the timing of sea level change over parts of the last glacial cycle is consistent with the predictions of the Astronomical Theory.  Two Devils Hole calcite subsamples record identical ²³¹Pa and ²³⁰Th ages, suggesting that the chronology of this climate record is accurate."

This is the single most important cross-check in the subject and the one popular treatments skip.  ²³¹Pa sits in the ²³⁵U chain with a 32,760 yr half-life; ²³⁰Th sits in the ²³⁸U chain with a 75,584 yr half-life.  Different parent, different daughter, different element, different chemical separation — and the ages agree.  The sample-by-sample agreement in years and per cent is in this paper's tables, which were not obtained; the article must therefore quote the abstract's word "identical" and cite Fairbanks et al. 2005/2006 for the operational tolerance actually used (2σ analytical error).

Rigorous quality control criteria for screening coral samples and radiocarbon calibration data based on ¹⁴C, ²³⁰Th/²³⁴U/²³⁸U and ²³¹Pa/²³⁵U dated corals

Fairbanks, R. G., R. A. Mortlock, T.-C. Chiu, L. Cao, A. Kaplan, T. P. Guilderson, T. W. Fairbanks and A. L. Bloom.  Quaternary Science Reviews 25 (2006): 3084–3087.  https://doi.org/10.1016/j.quascirev.2006.06.005

topic: concordance-pa-th camp: mainstream type: correspondence access: OA direction: mixed

Obtained as a PDF with a text layer from the open directory rainbow.ldeo.columbia.edu/~alexeyk/Papers/Fairbanks_etal2006.pdf.  This route also supplies Fairbanks et al. 2005 and is worth remembering.

The most operationally useful document in the whole file.  It sets out the six-category ranking the Barbados group applies to every coral, and the categories are built around the Pa/Th cross-check:

• Category I — marine environment only, replicated ¹⁴C and replicated ²³⁰Th ages agreeing within 2σ, ages in stratigraphic order.
• Category II — marine only, not replicated or not replicated to 2σ, ages in stratigraphic order.
• Category III — exposed to vadose fresh water, and ²³¹Pa/²³⁵U and ²³⁰Th/²³⁴U/²³⁸U ages agree within 2σ.
• Category IV — exposed to vadose fresh water, dated by ²³⁰Th only.
• Category V — exposed to the phreatic lens, Pa and Th ages agree within 2σ. Not used.
• Category VI — exposed to the phreatic lens, not validated by concordant dates. Not used.

Other criteria stated verbatim: X-ray diffraction must show "no detectable calcite" at a documented 0.2 % detection limit; uranium concentration must lie in the modern range for the species; "the δ²³⁴U_initial of coral samples must be between 138 and 150 per mil"; ²³⁰Th precision better than ±3.0 ‰ (1σ) over the whole 0–50,000 yr range.

It also records the mainstream's own internal fight, which is worth more than any critic's summary.  Quoting Reimer et al. 2006 against themselves: "Fairbanks et al. (2005) and Chiu et al. (2005) insist that a protocol of 'no detectable calcite' be adopted as the new standard.  This may well be good advice, but doing so would exclude nearly all of the (published) coral data presently available."  Fairbanks replies with Figure 1: apply the criteria to the Yokoyama et al. (2000) calibration data and "nearly all of the Yokoyama et al. (2000) data fail at one or more levels."

Tagged mixed because it cuts both ways.  It shows the method has a real, published, quantitative screening protocol; it also shows that most published coral data of the day did not pass it.

Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired ²³⁰Th/²³⁴U/²³⁸U and ¹⁴C dates on pristine corals

Fairbanks, R. G., et al.  Quaternary Science Reviews 24 (2005): 1781–1796.  https://doi.org/10.1016/j.quascirev.2005.04.007

topic: calibration-14c camp: mainstream type: measurement access: OA direction: mixed

Same open directory route.  Sets out the sampling and mass-spectrometric method: ²³⁰Th and ²³¹Pa ages "in a single coral fragment" by MC-ICP-MS on fragments as small as 0.5 g; U and Th isotope ratio precision "better than ±0.08 % and ±0.3 % (2 RSD)"; U-series and ¹⁴C samples drilled as two concentric cores from the same 4 mm slab so the two dates come from the same few millimetres of skeleton.  Repeats the δ²³⁴U_initial window of 138–150 ‰ and explains why it is skewed below the modern seawater value of 146 ‰ (Delanghe et al. 2002; Cutler et al. 2004).  Detailed statistics are in an online Appendix Table 1 that was not obtained.

The cross-check against radiocarbon

Calibration of the ¹⁴C timescale over the past 30,000 years using mass spectrometric U-Th ages from Barbados corals

Bard, E., B. Hamelin, R. G. Fairbanks and A. Zindler.  Nature 345 (1990): 405–410.  https://doi.org/10.1038/345405a0

topic: calibration-14c camp: mainstream type: measurement access: OCR direction: undercuts

Obtained as a scanned PDF with no text layer via the Wayback Machine copy of the now-decommissioned doc.rero.ch/record/210333/files/PAL_E4371.pdf, then OCRed locally with tesseract at 300 dpi.  Table 1 recovered in full, and re-typed into research/chain-equilibrium.ts.

The founding paper of the U-Th/¹⁴C comparison.  Nineteen Barbados corals with paired ages, nine duplicate U-Th analyses agreeing within 2σ, and — the authors' own emphasis — "it is remarkable that there is not even a single stratigraphic inversion in the U-Th data."  Precision "typically better than 100 yr (at 2σ) for ages between 6 and 20 kyr."  Initial ²³⁴U/²³⁸U ratios "fall in the range of modern sea water (1.14–1.15)" for every deglacial sample.

The headline number: "the Th ages are consistently older than the ¹⁴C ages, with a maximum difference of ~3.5 kyr at ~20 kyr BP," equivalent to "a Δ¹⁴C of ~400–500 ‰ above the present-day reference level for ages between 18 and 22 kyr BP."  Recomputing Δ¹⁴C from the published table (see research/chain-equilibrium.out.txt) reproduces 445–513 ‰ across that window, so the authors' stated range checks out.

Why this cuts against the young-earth argument, and it is not the obvious reason.  The three youngest samples fall inside the tree-ring calibration and the U-Th ages agree with dendrochronology — an independent, decay-free clock.  And the ¹⁴C age runs younger than the U-Th age at every one of the nineteen levels, which is the opposite of the sign accelerated ¹⁴C decay predicts.  Cross-reference agents/memory/decay-free-clocks.md, which works the sign test out in detail.

The IntCal20 Northern Hemisphere radiocarbon age calibration curve (0–55 cal kBP)

Reimer, P. J., et al.  Radiocarbon 62 (2020): 725–757.  https://doi.org/10.1017/RDC.2020.41

topic: diagenesis camp: mainstream type: compilation access: on-disk direction: supports

Already on disk as sources/papers/reimer-2020_intcal20.pdf.  CC-BY.

The most damaging admission about coral U-series in the mainstream literature, and it is the calibration community's own.  At p. 739, verbatim: "some of the coral data used in IntCal13 exhibit wide scatter in Δ¹⁴C (~500 ‰), especially around 37 kyr BP… It is likely that diagenesis due to exposure to freshwater occurred when these corals were above sea level during the lowstand of the Last Glacial Maximum… This effect appears to have been particularly prevalent in corals from areas with rapid uplift such as Vanuatu for which coral Δ¹⁴C appears very elevated (>1100 ‰ around 27–29 cal kBP; Cutler et al. 2004)… It was therefore decided to remove all coral data older than 25 cal kBP for construction of the IntCal20 curves to avoid the potential inclusion of erroneous data.  Further work is needed to develop a way of identifying which corals are affected by diagenesis."

Note carefully what this does and does not concede.  It concedes that coral U-Th/¹⁴C pairs older than 25 cal kBP are unreliable enough to discard wholesale.  It does not concede that the U-Th ages are wrong: the stated cause is freshwater diagenesis altering the ¹⁴C, and the calibration beyond 25 kBP is carried instead by speleothems whose U-Th ages are trusted.  Any use of this quotation must state both halves.  The locator was confirmed by counting running heads in the on-disk PDF (even-page heads at text lines 769 and 891 bracket the paragraph at lines 869–882).

Same paper, on the speleothem side: Hulu stalagmites H82, MSD and MSL give posterior dead-carbon fractions of 472, 470 and 481 ± 50 ¹⁴C yr — three stalagmites in one cave agreeing to 11 ¹⁴C years — while the Bahamas speleothem needs 1523 ± 208 and 2891 ± 323 ¹⁴C yr and is downweighted.  Numbers already verified in agents/memory/decay-free-clocks.md; not re-derived here.

The cross-check against layer counting

A high-resolution absolute-dated late Pleistocene monsoon record from Hulu Cave, China

Wang, Y. J., H. Cheng, R. L. Edwards, Z. S. An, J. Y. Wu, C.-C. Shen and J. A. Dorale.  Science 294 (2001): 2345–2348.  https://doi.org/10.1126/science.1064618

topic: layer-counting camp: mainstream type: measurement access: abstract-only direction: undercuts

Full text NOT obtained (science.org paywalled).  Publisher abstract obtained verbatim from NCBI E-utilities, PMID 11743199.  Verbatim: "Between 11,000 and 30,000 yr. B.P., the timing of changes in the monsoon, as established with ²³⁰Th dates, generally agrees with the timing of temperature changes from the Greenland Ice Sheet Project Two (GISP2) core, which supports GISP2's chronology in this interval."

The quantitative version of this comparison — "GICC05 agrees with the Hulu Cave time scale within 800 yrs" over 60 kyr, Kleegruben under 300 yr, Socotra's Moomi Cave as the one cave that does not fit — is already verified and recorded in agents/memory/decay-free-clocks.md from Svensson et al. 2008.  Use those numbers; do not re-derive them.  Likewise the Suigetsu varve-versus-U-Th residual table (−32 yr at 10–15 ka rising to +2,744 yr at the deepest level, a 5.4–7.5 % shortfall in the count) is computed in house at html/unpublished-ai/radiometric-concordance/research/suigetsu-varve-vs-uth.py.

The cross-check against orbital forcing, and the dispute it produced

Continuous 500,000-year climate record from vein calcite in Devils Hole, Nevada

Winograd, I. J., T. B. Coplen, J. M. Landwehr, A. C. Riggs, K. R. Ludwig, B. J. Szabo, P. T. Kolesar and K. M. Revesz.  Science 258 (1992): 255–260.  https://doi.org/10.1126/science.258.5080.255

topic: orbital-forcing camp: mainstream type: measurement access: abstract-only direction: mixed

Full text NOT obtained.  science.org paywalled; the USGS Publications Warehouse record (id 70016979) carries no file, only a thumbnail.  Publisher abstract obtained verbatim from NCBI E-utilities, PMID 17835123, and the same abstract independently from the USGS Publications Warehouse JSON API — two routes, byte-identical.

Verbatim: "δ¹⁸O variations in a 36-centimeter-long core (DH-11) of vein calcite from Devils Hole, Nevada, yield an uninterrupted 500,000-year paleotemperature record… The chronology for this continental record is based on 21 replicated mass-spectrometric uranium-series dates.  Between the middle and latest Pleistocene, the duration of the last four glacial cycles recorded in the calcite increased from 80,000 to 130,000 years; this variation suggests that major climate changes were aperiodic.  The timing of specific climatic events indicates that orbitally controlled variations in solar insolation were not a major factor in triggering deglaciations.  Interglacial climates lasted about 20,000 years.  Collectively, these observations are inconsistent with the Milankovitch hypothesis."

This entry earns its place because of the disagreement, not the agreement.  Devils Hole is subaqueous vein calcite, not a stalagmite: it grew slowly under water in a fault-controlled fissure, is dense and clean, and its U-series chronology was strong enough that for two decades the field preferred to doubt Milankovitch rather than doubt the dates.  A dating method that survived being pointed at the orbital theory and used to attack it is not a method being tuned to a preferred answer.

Reconciliation of the Devils Hole climate record with orbital forcing

Moseley, G. E., R. L. Edwards, K. A. Wendt, H. Cheng, Y. Dublyansky, Y. Lu, R. Boch and C. Spötl.  Science 351 (2016): 165–168.  https://doi.org/10.1126/science.aad4132

topic: orbital-forcing camp: mainstream type: measurement access: abstract-only direction: mixed

Full text NOT obtained.  Abstract verbatim from NCBI E-utilities, PMID 26744404.

Verbatim: "previous versions of the iconic Devils Hole (Nevada) subaqueous calcite record exhibit shifts to interglacial values ~10,000 years before orbitally forced ice age terminations, and interglacial durations ~10,000 years longer than other estimates.  Our measurements from Devils Hole 2 replicate virtually all aspects of the past 204,000 years of earlier records, except for the timing during terminations, and they lower the age of the record near Termination II by ~8000 years, removing both ~10,000-year anomalies."

Twenty-four years of a published, headline-grabbing conflict between U-series dates and orbital theory, resolved by going back and re-dating a second core from the same site.  Note what changed and what did not: the δ¹⁸O record replicated, the ages near the terminations moved by ~8 kyr out of ~130 kyr, about 6 %.

Comment on "Reconciliation of the Devils Hole climate record with orbital forcing"

Coplen, T. B.  Science 354 (2016): 296.  https://doi.org/10.1126/science.aaf8074

topic: orbital-forcing camp: mainstream type: correspondence access: abstract-only direction: supports

Abstract verbatim from NCBI E-utilities, PMID 27846528.  A co-author of the 1992 paper refusing to concede.  Verbatim: "Moseley et al's… preferred-Termination-II age is subjective, as evidenced by variation in their Termination-II ages of 2500 years per meter.  Termination-II-age bias decreases to zero at ~1.5 meters below the present-day water table, if one assumes linear variation with core-sample height.  Maintaining the required gradient of thorium isotope ²³⁰Th over 3.6 meters for 1000 years, much less 10,000 years, seems exceedingly unlikely."

Tagged supports because it is a working U-series geochemist, in Science, saying that a published set of ²³⁰Th ages varies systematically with sampling position by 2,500 years per metre.  There is a second comment (Science 354:296, doi 10.1126/science.aaf7718) and a response by Moseley et al. (doi 10.1126/science.aaf8679); neither was obtained.

Where the method genuinely fails

An open-system model for U-series age determinations of fossil corals

Thompson, W. G., M. W. Spiegelman, S. L. Goldstein and R. C. Speed.  Earth and Planetary Science Letters 210 (2003): 365–381.  https://doi.org/10.1016/S0012-821X(03)00121-3

topic: open-system camp: mainstream type: model access: abstract-only direction: supports

Full text NOT obtained; Crossref carries no abstract for this record either, only the bibliographic data (which corrects the DOI given in the research brief — it is …(03)00121-3, not …(03)00138-6).

Open-system coral ages reveal persistent suborbital sea-level cycles

Thompson, W. G. and S. L. Goldstein.  Science 308 (2005): 401–404.  https://doi.org/10.1126/science.1104035

topic: open-system camp: mainstream type: model access: abstract-only direction: supports

Abstract obtained verbatim from the Crossref API.  Verbatim: "suborbital-frequency sea-level change has been difficult to resolve, primarily because of problems with uranium/thorium coral dating.  Here we use a new approach that corrects coral ages for the frequently observed open-system behavior of uranium-series nuclides."

A mainstream concession in Science that open-system behaviour in corals is not rare but "frequently observed," and serious enough to have obscured a real climate signal.  The strongest single sentence available for the young-earth side of this article — but note it is an argument for correcting ages, not for abandoning them, and the correction model has its own critics.

The young-earth literature

The short finding, revised 30 August 2026 after a five-venue sweep of the creationist literature: there is one serious engagement and a handful of adjacent claims.  The serious one is Mogk 2023, an International Conference on Creationism paper that names the same four long-lived intermediates this article's central bound turns on, concludes that decay acceleration must have been pulse-like, and calls for exactly the measurement Hu et al. made two years later.  The rest is (a) Silvestru's recrystallisation and contamination objection, which is about the clock's chemistry and is the best of the adjacent claims; (b) an argument that speleothems can grow much faster than assumed, which is about growth rates and not about the ²³⁰Th clock, together with Cox's 2021 partial retraction of its popular form; (c) an argument that speleothem dates conflict with the expected Ice Age hiatus; (d) one passing remark that using U-Th to calibrate ¹⁴C is circular; and (e) a two-sentence misdescription of the method in the movement's most-read outlet.  Outside Mogk, no young-earth author found has engaged the ²³¹Pa/²³⁰Th concordance, the detrital ²³²Th correction, or the Cheng 2013 half-life determination.  Snelling's ARJ work on ²³⁴U mobility bears on the δ²³⁴U_initial screening criterion without ever being aimed at it.

An earlier version of this page and of the article said the ground was empty.  That was wrong, and the correction is made in the article's own voice rather than by deletion.

Tapping the hourglass: disequilibrium relaxation following accelerated nuclear decay

Mogk, Nathan.  In J. H. Whitmore (ed.), Proceedings of the Ninth International Conference on Creationism, Cedarville, Ohio, 2023, pp. 327–345.  https://cedarville.tind.io/record/21188

topic: creationist-critique camp: creationist type: model access: OA direction: mixed

Downloaded as a text-layer PDF from cedarville.tind.io/record/21188/files/20_Mogk_1493_Tapping_the_Hourglass.pdf and read locally with pdftotext -layout.  Folios are exact:  PDF page N carries printed page 326 + N, confirmed against the running folio 339 at the foot of PDF page 13.  Now in the source library as mogk-2023.

The most technically serious young-earth engagement with uranium-series disequilibrium that exists.  Three things in it matter here, all on p. 339.  He identifies ²³⁴U, ²³⁰Th, ²²⁶Ra and ²³¹Pa as the four nuclides long-lived enough to remember an acceleration episode, which is the same observation this article's δ²³⁴U bound rests on.  He concludes "that to first order, decay acceleration during the Flood must be pulse-like."  And he writes that measurements of the intermediate isotopes "should be prioritized," which is precisely the class of measurement Hu et al. 2025 made — and the answer came back null.

Tagged mixed.  It is the strongest thing on that side.  Mogk himself argues that "to first order, decay acceleration during the Flood must be pulse-like" (p. 339), and mentions post-Flood acceleration only by citing Oard;  he does not propose it.  His 66 million radiometric years for the modern period, divided by Ussher's duration for it, give a time-averaged acceleration of about 1.5 × 10⁴ on his own two inputs, which the article uses as a scale figure no model claims:  at that rate every carbonate would saturate and leave no readable age.  The post-Flood placement in print is Oard 2021 (below).  His reservoir-relaxation mechanism is aimed at magmatic systems and does not transfer to a coral, whose reservoir is seawater and cannot hold a thorium excess for any length of time.

One limitation of the source itself: the table of time-averaged acceleration factors on p. 339 is an image with no text layer, so its printed values were not recovered.  The 1.5 × 10⁴ figure used here is arithmetic on Mogk's own stated inputs, and both the article and the footnote say so.

Rock layers and caves

Silvestru, Emil, and Tas Walker.  creation.com feedback, 18 May 2011 (updated 30 July 2011).  https://creation.com/en/articles/strata-cave-dating

topic: creationist-critique camp: creationist type: correspondence access: OA direction: mixed

Fetched as raw HTML with a browser user-agent and detagged locally; the site returns HTTP 403 to a bare curl.  Publication date confirmed from the page's own datePublished metadata.  A feedback reply with no page numbers, so quotations are located by paragraph.

The best objection anyone on the young-earth side has made to ²³⁰Th dating of speleothems, and it is earlier and more technical than the 2012 Creation piece that this article previously treated as Silvestru's main statement.  Verbatim: "The ²³⁴U–²³⁰Th method applied to speleothems has yielded so many erroneous ages that we have lost count… there are many uncontrollable variables, from contamination (never properly countered regardless the method), to recrystallization (which has long been ignored on a microscopic scale, most assessments being made on megascopic grounds)."

Recrystallisation is a real failure mode:  it moves U and Th about inside a sample without either leaving it, so a bulk analysis can look clean while the age is wrong.  The parenthesis is the sharp part, because calcite-to-calcite recrystallisation is invisible to the XRD screen that catches aragonite inversion in corals, and speleothem screening falls back on petrographic fabric, which is a judgement rather than a number.  The article states this, states what the field does about it, and states the residual.

Tagged mixed for two reasons.  Silvestru offers "we have lost count" and supplies no count, and no case of a screened speleothem shown to be recrystallised and wrong.  And in the same reply he offers, as corroboration, "numerous speleothems grown on show cave facilities, from concrete pavements to hand rails and even cabling" — a growth-rate observation used as a dating argument, which his own organisation told its readers to stop doing ten years later.

Speleothem growth: in caves vs man-made structures

Cox, Gavin.  creation.com feedback, 4 December 2021.  https://creation.com/en/articles/speleothem-growth

topic: growth-rates camp: creationist type: correspondence access: OA direction: undercuts

Fetched as raw HTML with a browser user-agent and detagged locally.  Date confirmed from the page's own datePublished metadata.

A creationist partially retracting a creationist argument, on chemistry, in print.  Cox opens: "Biblical creationists do need to be careful about how they use evidence, and as we shall see, stalactites growing under modern concrete bridges are not directly analogous to how speleothems grow in natural caverns."  His reason is that calthemites growing from concrete leachate at pH above 9 absorb CO₂ from the air, while cave speleothems grow from near-neutral bicarbonate solution and degas it — opposite reactions, so the rate of one says nothing about the rate of the other.  He concludes that "drawing comparisons with modern concrete stalactites to that of cave formations should only be done in a qualified sense."

Tagged undercuts because it undercuts the young-earth argument it is discussing, and supports this article's own insistence on keeping growth rate separate from age.  Cox does not abandon the comparison; he keeps it as an object lesson and corrects a sceptical site on a point of fact along the way, since the man-made deposits are calcite rather than gypsum, verified by Vance Nelson's X-ray diffractometry at five sites.

Problems with the U-Pb Radioisotope Dating Methods—2. U and Pb Mobility

Snelling, Andrew A.  Answers Research Journal 11 (2018): 85–139.  https://answersresearchjournal.org/problems-radioisotope-dating-u-pb-2/

topic: open-system camp: creationist type: review access: OA direction: mixed

Fetched as raw HTML and detagged locally.  The typeset PDF was downloaded from assets.answersresearchjournal.org/doc/v11/problems2_u_and_pb_mobility.pdf and read locally, and the detagged HTML agrees with it word for word.  Page locators are pinned from the PDF running heads (printed page = PDF page + 84, anchored at folios 87 and 139).  The PDF's own first-page header misprints the volume as 10 and the range as 85–139;  volume 11 is the 2018 volume and 139 is the last folio, so the range used here is 11 (2018): 85–139.  Now in the source library as snelling-2018c.

Not about U-series dating, and included because it supplies the strongest available counter to this article's central bound.  Its opening list of assumptions includes "Deviations of the ²³⁴U/²³⁸U ratio from secular equilibrium," and the section "The Extent and Cause of Pb Mobility" reports Davis and Krogh's finding of "preferential leaching of radiogenic Pb isotopes and ²³⁴U from damaged crystal lattice sites," corroborated by "the observation of significant ²³⁴U anomalies in groundwater and the oceans."

Tagged mixed.  Snelling never turns this against U-series dating, but a well-read critic would, and the article meets it first.  The answer is that mobility changes how many atoms are in a rock and cannot change the ratio of two decay constants;  that alpha-recoil leaching is directional, so it drives δ²³⁴U away from zero rather than onto it;  and that mobility is the reason U-series practitioners screen on initial δ²³⁴U at all.  The objection is the screening criterion.  Note also that this paper is where Snelling states plainly that U-Pb and U-series read the same decay chain, which is why the article no longer calls it a different one.

How Reliable Are Dates for Human Fossils?

Snelling, Andrew A.  Answers magazine, 1 September 2018.  https://answersingenesis.org/geology/radiometric-dating/how-reliable-are-dates-human-fossils/

topic: creationist-critique camp: creationist type: popular access: OA direction: mixed

Fetched as raw HTML and detagged locally.  Date confirmed from the page's own datePublished metadata.

Answers in Genesis's only description of uranium-series dating, and it describes a different method.  Verbatim: "Another method occasionally used is called uranium-series dating.  As uranium decays to lead, it passes through a series of other elements.  Measuring the quantities of those elements enables us to estimate an age based on how far along the process has gone.  For this method to work with human artifacts or bones, however, they need to be entombed in limestone containing uranium, such as that in cave deposits."

That is progress along the chain toward Pb, which is U-Pb dating, not ²³⁰Th ingrowth in a carbonate that excluded Th at formation.  And the geochemistry is inverted: the method works because Th is insoluble and U is soluble, so what matters is that the water carries uranium and no thorium, not that the limestone "contains uranium."  Included as the clearest available measure of how thin the engagement is.

Caves and age: how radioactive dating confuses the situation

Silvestru, Emil.  Creation 34(1) (January 2012): 46–48.  Web version published 19 March 2009, updated 29 July 2013.  https://creation.com/en/articles/caves-and-age

topic: creationist-critique camp: creationist type: popular access: OA direction: supports

Fetched as raw HTML with curl and detagged locally.  Silvestru holds a doctorate in karst sedimentology, so this is the most technically credentialled young-earth source on caves.

Two arguments.  The first is a geomorphological one, and it is the better of the two: "the surface of limestone terrains above caves changes dramatically in short periods of time.  And any change at the surface also changes the location of the water droplets inside the cave.  However, the stalagmites do not indicate any changes.  So the conclusion is simple: they cannot be that old."  This is a real observation deserving a real answer.  It is not, however, an argument about ²³⁰Th.

The second is the Vancouver Island case.  Speleothems there "have yielded radiometric ages of between 12 and 18 thousand years," which is during the Fraser Glaciation when up to 2 km of ice covered the island and speleothems should not have grown.  Silvestru: "rather than question the radio-isotopic dates… some scientists have proposed that the 2-km-thick ice cover melted and grew back in a few thousand years."  He concludes that the caves formed after the Flood and the speleothems "have recorded the post-glacial climate variations over the last 4,000 years."

What is missing is the arithmetic.  If the speleothems really grew in under 4,000 years and read 12,000–18,000, the ²³⁰Th clock must be running 3–4.5× fast, and Silvestru neither says so nor proposes a mechanism.

Rapid growth of caves and speleothems, parts 1–3

Oard, Michael J.  Journal of Creation 34(1) (April 2020): 71–78; 34(2) (August 2020): 90–97; 34(2) (August 2020): 98–104.  https://creation.com/en/articles/speleothems-1, https://creation.com/en/articles/speleothems-2, https://creation.com/en/articles/speleothems-3

topic: growth-rates camp: creationist type: review access: OA direction: mixed

Fetched as raw HTML and detagged locally.  The fullest young-earth treatment of speleothems in print, and it is careful, well-referenced work on the growth-rate question — five controlling variables (drip-water calcium supersaturation, cave temperature, ventilation, drip rate, film thickness) plus evaporation, with the conclusion that post-Flood Ice Age growth "could easily be over a hundred times that of today in some caves," against present-day rates of "around 0.1 to 2 mm/yr… but can vary from zero to more than 5 mm/yr."

Keep this claim separate from the dating claim.  Fast growth is compatible with correct ²³⁰Th ages; a stalagmite that grew in a century simply has a hundred years of ²³⁰Th ingrowth spread over a lot of calcite.  The two claims only meet if the U-Th ages are also wrong, and Oard does not argue that — he assumes it.

Tagged mixed because of one sentence in part 3 that undercuts the series' own method: "In searching the literature for growth rates, estimated growth rates that depend upon radiometric methods were avoided, since they always seem to greatly exaggerate the time."  That is the conclusion being used as a filter on the evidence.  A skeptical reader will spot it immediately, and the article should say so plainly rather than let a critic say it first.

Part 1 also records, accurately, that "Researchers use uranium series dating for most speleothems… A few other dating methods are also applied, especially beyond 500,000 years, the maximum range for the uranium series method.  Regardless, very few claim any speleothem is older than 500,000 years."  Part 3 correctly describes the dead-carbon-fraction problem for ¹⁴C in speleothems.

Circular reasoning in the dating of deep seafloor sediments and ice cores: the orbital tuning method

Hebert, Jake.  Answers Research Journal (2016).  https://answersingenesis.org/age-of-the-earth/circular-reasoning-dating-deep-seafloor-sediments-and-ice-cores-orbital-tuning-method

topic: creationist-critique camp: creationist type: review access: OA direction: mixed

Fetched as raw HTML and detagged locally.  Contains the only direct young-earth engagement with Bard et al. 1990 that these searches found, and it is one sentence: "it is fairly common for uniformitarian scientists to use one radioisotope dating method to calibrate another radioisotope dating method.  For instance, uranium-thorium ages for corals have been used to calibrate the carbon-14 timescale (Bard et al. 1990).  Of course, the fact that radioisotope dates need to be 'calibrated' or 'synchronized'… is a clear indication that such dates are not absolute."

The observation is true and the inference does not follow.  Calibrating ¹⁴C against U-Th is not circular, because the two methods share no assumption: ¹⁴C is a beta-decaying cosmogenic nuclide whose production rate varies, U-Th is an alpha-decay ingrowth clock in a closed carbonate.  The calibration corrects for the known variability of the first using the stability of the second, and the result is then checked against tree rings and varve counts that involve no decay at all.

The searches that were run

Recorded so nobody repeats them.  The first pass, on 30 August 2026, used site searches and direct fetches.  It was then superseded by a corpus-level sweep run 25–30 August 2026, which is what the article now prints, because a site search cannot establish a negative and a full-text corpus can.

The boundary that has to be stated with the result.  Only the ICC corpus was read at body-text level.  The creation.com, ARJ and CRSQ sweeps ran over titles, abstracts and site indexes, with full text pulled only for hits, so a passing sentence buried in an off-topic paper would be missed there.  ICR is excluded from any negative finding.

Conclusion to state in the article: on the evidence of these searches, one young-earth author has engaged uranium-series disequilibrium as a method, and he is Nathan Mogk;  nobody else found has.  It has engaged speleothem growth rates, which is a different question, and it has engaged U-Pb, which is the same chain read at its stable terminus over a different time range — Snelling says so himself.  Say so explicitly, and show the table.

Cross-references, not duplicated here

• agents/memory/decay-free-clocks.md — Suigetsu varves versus U-Th (residuals computed in house), the Hulu/GICC05 comparison, the IntCal20 dead-carbon fractions, the ¹⁴C sign test. Everything there is already verified; take the numbers, do not redo the work.
• agents/memory/radiocarbon.md and html/unpublished-ai/radiocarbon/ — the ¹⁴C side of the calibration.
• agents/memory/radiometric-failure-modes.md — the Lake Mungo 3 case, where ESR, Th/U and Pa/U all agreed on 62 ± 6 ka and all were wrong by 55 %, because all three read the same uranium in the same open-system bone. This is the single best-documented failure of U-series concordance and it belongs in the article's objections section.
• agents/memory/ice-age.md — Huon Peninsula terraces and the α-spectrometric versus TIMS Th/U re-evaluation; also flags Devils Hole versus orbital timing at Termination II as an open item, which this file now closes.
• sources/index.tsv key cheng-2016c — the 641.3 kyr Chinese speleothem composite, already on disk as public-domain NOAA data.

Was each source used?

Required check before the article could be called finished:  every source worked up here is either cited in the article or marked below as considered and not used.  Result as of 30 August 2026, after the creationist-literature sweep added five sources: every entry is cited.

One source added after the catalogue was written

Winograd, I. J., J. M. Landwehr, T. B. Coplen, W. D. Sharp, A. C. Riggs, K. R. Ludwig and P. T. Kolesar, "Devils Hole, Nevada, δ¹⁸O record extended to the mid-Holocene," Quaternary Research 66 (2006): 202–212.  https://doi.org/10.1016/j.yqres.2006.06.003

topic: orbital-forcing camp: mainstream type: measurement access: abstract-only direction: background

Located during the writing phase, by a Crossref bibliographic query, to settle the unpinned "570 ka" figure the research brief carried.  Abstract obtained as JSON from the Crossref REST API and read locally.  Verbatim: "The mid-to-late Pleistocene Devils Hole δ¹⁸O record has been extended from 60,000 to 4500 yr ago."

This paper extends the Devils Hole record toward the present, not into the deeper past, so it does not support a 570,000-year chronology.  The figure was dropped from the article and the whole matter is recorded in quarantine.

Added with the 2026-10-20 correction

Humphreys 2000 (humphreys-2000), "Accelerated Nuclear Decay:  A Viable Hypothesis?", the RATE volume of 2000, pp. 333-380.  Read from the source library PDF.  RATE's own statement of when decay was accelerated:  "three episodes:  one in the early part of the Creation week, another between the Fall and the Flood, and the third during the year of the Genesis Flood" (p. 333, and the Figure 2 caption, p. 341).  Nothing after the Flood.  Cited in the article for that position.

Oard 2021 (oard-2021f), "Much Greater Cosmic Rays During the Ice Age and Before," Creation Research Society Quarterly 58(1):30-48.  Read from the source library PDF.  The one young-earth author found who puts accelerated decay after the Flood:  "during the Flood and Ice Age" (p. 30) and "accelerated radiometric decay continued for a while after the Flood" (p. 39).  He gives no acceleration factor, and concedes it "presents a problem of too much radiation during the Ice Age" (p. 44).  Cited in the article for that position and tested against the required factors.