The literature

This page exists so nobody has to take 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 on amino acid racemization (AAR) — the founding kinetics, the Californian palaeoindian episode in which the method's own inventor published ages that were wrong by a factor of ten, the intracrystalline rebuild that partly repaired it, the mainstream survival limits it imposes on ancient protein, and the two very different young-earth arguments built on all of that.

It is deliberately not a reading list of things that agree with this site.  Sources are tagged by the direction they cut, and a reader who wants only the strongest material against the young-earth argument can filter for undercuts and read those.

How to read an entry

Measurement or model.  A measured D/L ratio in a shell is an observation.  A "racemization age" is that observation pushed through a rate constant borrowed from a different sample, and it inherits every assumption in that borrowing — above all the assumed temperature history.  Both are useful.  They are not the same kind of thing, and conflating them is how nearly every bad argument on this subject gets made, on both sides.

Closed or open system.  The single most important distinction in this field.  Amino acids sitting in bone hydroxyapatite can leach out, and contaminating L-amino acids can leach in;  amino acids trapped inside the crystal lattice of a mollusc shell cannot.  Bone AAR failed largely because bone is an open system.  The intracrystalline method works largely because it is not.  Every entry says which it is.

Direction.  Whether the source supports, undercuts, or complicates the young-earth argument.  Assigned by what the source shows, not by what its authors believe — several mainstream papers are tagged supports, and the most detailed creationist paper on the subject is tagged mixed because half of it undercuts the other half.

Camp.  Disclosure, not a verdict.

Field definitions

Founding the method

Racemization Reaction of Aspartic Acid and Its Use in Dating Fossil Bones

Bada, Jeffrey L., and Reiner Protsch.  Proceedings of the National Academy of Sciences 70(5):1331-1334  (May 1973).

doi:10.1073/pnas.70.5.1331 · PMC433490 · route that worked: curl on europepmc.org/articles/PMC433490?pdf=render

topic: bone-dating camp: mainstream type: measurement access: OA system: open direction: mixed

Key figures (all p.1331-1333): aspartic acid racemization in bone has a half-life at 20 °C of "about 15,000-20,000 years" (p.1331, defined as time for D/L to reach 0.333);  the calibration bone from the Naisiusiu Beds, Olduvai Gorge, gave a collagen ¹⁴C age of 17,550 ± 1,000 yr (UCLA-1695) and D/L(Asp) = 0.32, yielding k(Asp) = 1.48 ± 0.09 × 10⁻⁵ yr⁻¹ (p.1333);  the Ndutu Beds bone at D/L = 0.72 then gave 56,000 ± 3,500 yr;  the Eyasi I hominid at D/L ≈ 0.5 gave 34,000 yr.  The t = 0 correction term is 0.14, from a modern bovine bone measured at D/L = 0.07 (p.1333).

The paper that started bone AAR dating, and the paper that states the method's fatal assumption in its own abstract:  "The only assumption required with this approach is that the average temperature experienced by the 'calibration' sample is representative of the average temperature experienced by older samples" (p.1331).  Bada and Protsch judged that assumption safe because glacial-cycle temperature swings in the tropical Atlantic and in a New Zealand cave amounted to only about 0.5 °C over 20,000 years (p.1333).  That judgement is what later collapsed.

Disclosure a skeptic will find anyway, and it is now sourced: the co-author, Reiner Protsch, was forced to retire from the University of Frankfurt in February 2005 after a commission found "falsehoods and manipulations" in his dating work, reported contemporaneously by The Guardian (see the Harding 2005 entry below).  The UCLA-1695 calibration date was measured "by use of the method described by Protsch."  This is not by itself evidence that this particular date was faked, and the article does not present it as such.  It is a reason to treat the founding calibration as unconfirmed.  This material was in quarantine.md on the morning of 30 August 2026 and was released the same day once a contemporaneous source replaced the secondary one.

The Californian palaeoindian episode

New Evidence for the Antiquity of Man in North America Deduced from Aspartic Acid Racemization

Bada, Jeffrey L., Roy A. Schroeder, and George F. Carter.  Science 184(4138):791-793  (17 May 1974).

doi:10.1126/science.184.4138.791 · PMID 4595240

topic: california-episode camp: mainstream type: measurement access: NOT OBTAINED system: open direction: supports

The paper that assigned ages of roughly 48,000 years to the Del Mar skeleton and up to 70,000 years to other Californian material.  Not obtained in full text — see the NOT OBTAINED list in research/_brief.md for every route tried.  Its numbers are quoted here only where a source that was obtained reproduces them.

Six Decades of Radiocarbon Dating in New World Archaeology

Taylor, R. E.  Radiocarbon 51(1):173-212  (2009).

doi:10.1017/S0033822200033774 · route that worked, exact URL confirmed 2026-08-30: curl https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033822200033774 returns the free full PDF (the /core/journals/radiocarbon/article/... landing page 500s)

topic: california-episode camp: mainstream type: review access: OA system: n/a direction: supports

Key figures, all p.183: AAR assigned 70,000 yr to Sunnyvale, >50,000 to Haverty/Angeles Mesa, 48,000 to Del Mar and 23,000 to Yuha.  AMS ¹⁴C on XAD-purified collagen gave Del Mar 5380 ± 390 BP (AA-2666) and 4830 ± 200 BP (AA-2665);  Sunnyvale 6300 ± 400 BP (OxA-187) down to 3600 ± 600 BP (UCR-1437A/AA-50).  "In each case, the redating determined that all of these human skeletal samples previously assigned Pleistocene ages were, in fact, of Holocene age."

The free replacement for the paywalled Taylor et al. 1985.  Same first author, cites that paper, and reproduces its numbers with laboratory codes.  Use this rather than spending a JSTOR read.

Amino Acid Racemization Dating of Fossil Bones

Bada, Jeffrey L.  Annual Review of Earth and Planetary Sciences 13:241-268  (1985).

doi:10.1146/annurev.ea.13.050185.001325 · bibcode 1985AREPS..13..241B · route that worked: NASA ADS page scan, curl https://articles.adsabs.harvard.edu/pdf/1985AREPS..13..241B, then 300 dpi pdftoppm + tesseract 5.5 OCR.  PDF page N = printed page 240 + N, anchored on the running heads at PDF pages 1 and 24.

topic: california-episode camp: mainstream type: review access: OA system: open direction: mixed

Key figures: Arrhenius fit ln k(Asp) (yr⁻¹) = 56.6 − 19.7 × 10³ T⁻¹ (p.248, Figure 4 caption), giving Ea = 39.1 kcal/mol;  Ea quoted separately as "about 38 ± 3 kcal mol⁻¹" (p.249);  "variations of ± 1° in the temperature of the depositional environment... would effect the rate of racemization in the fossil by about ± 25%" (p.249);  Olduvai Holocene-to-Pleistocene ground temperature difference ΔT ≈ 7-8 °C (p.259);  Laguna calibration skeleton assumed 17,150 ± 1470 yr, AMS ¹⁴C "only ~5000 yr old" (p.261);  revised k(Asp) = 6.043 × 10⁻⁵ yr⁻¹ against an original ~1.5 × 10⁻⁵ (pp.261-263);  in bone, pH between 3 and 8 does not affect racemization rate, because "the bone minerals effectively buffer the system" (p.249).

The single most valuable source in this article.  It is the method's inventor, in a mainstream review, explaining in print why his own published ages were wrong by an order of magnitude.  The load-bearing passage is p.264:  "An erroneously dated calibration sample will obviously yield erroneous racemization dates. If the Laguna and Los Angeles Man skeletons had been originally assigned the Holocene ages recently determined using the AMS-based radiocarbon method, skeletons such as those from Del Mar and Sunnyvale never would have yielded racemization ages of great antiquity."

Tagged mixed rather than supports because the same paper defends the method:  p.265, "The ages derived from the extent of amino acid racemization in a fossil bone seem generally to be reasonably accurate."  Bada blamed the calibration, not the chemistry, and did not abandon AAR.  Any article that presents him as having renounced it is misrepresenting a source a reader can check.

Kinetics, and why the simple model is not enough

Predicting Protein Decomposition: The Case of Aspartic-Acid Racemization Kinetics

Collins, M. J., E. R. Waite and A. C. T. van Duin.  Philosophical Transactions of the Royal Society B 354(1379):51-64  (1999).

doi:10.1098/rstb.1999.0359 · route that worked: White Rose Research Online green OA copy, eprints.whiterose.ac.uk/id/eprint/777/1/collinsmj1.pdf.  PDF page N = printed page 49 + N.

topic: kinetics camp: mainstream type: model access: OA system: lab direction: mixed

The paper that shows Asx racemization is not a simple reversible first-order reaction in real fossil material.  It proceeds through a strained cyclic succinimide intermediate whose formation is blocked inside an intact collagen triple helix, so in bone the measured D/L "reflects the ratio of non-helical (high proportion of D-Asx) to triple helical (L-Asx) collagen" (p.60).

Verbatim, p.60: "Despite the large number of experiments which have been conducted to derive kinetic parameters for Asx racemization, when applied to fossil material the pattern and rates are unpredictable."  And from the numbered summary on the same page:  "(i) estimating rates of Asx racemization by extrapolation from high temperatures is to be avoided... (iii) although they are the most widely used archaeological materials for Asx dating, bones and teeth are probably the worst materials to choose, due to the extreme conformational effect of the collagen triple helix... (vi) Asx racemization is not a reliable proxy for the extent of DNA depurination in bones."

Tagged mixed because it cuts both ways with equal force.  It is why the Californian bone dates failed — good for the young-earth reader.  It is also why any young-earth argument that leans on a precise extrapolated racemization half-life for bone is standing on the same sand.  Royal Truman quotes the "unpredictable" sentence approvingly and then builds a recalibration on the kinetics it condemns.

The intracrystalline rebuild

Closed-System Behaviour of the Intra-Crystalline Fraction of Amino Acids in Mollusc Shells

Penkman, K. E. H., D. S. Kaufman, D. Maddy and M. J. Collins.  Quaternary Geochronology 3(1-2):2-25  (2008).

doi:10.1016/j.quageo.2007.07.001 · PMC2727006 · route that worked: PMC full-text HTML, tags stripped locally.  The ScienceDirect CC-BY PDF returns HTTP 403 to curl.

topic: intracrystalline camp: mainstream type: measurement access: OA system: closed direction: undercuts

Key figures, all from the abstract: 48 h in concentrated NaOCl reduces the amino acid content to a residual intracrystalline fraction;  after 24 h in water at 140 °C, 1 % of amino acids leached from the intracrystalline fraction against 40 % from whole shell;  free amino acids retained at 55 % against 18 %;  inter-shell D/L variability in a single-age fossil gastropod population halved.

The measurement that repaired the method, and it is a measurement, not an assertion.  Bone AAR failed largely because bone is an open system;  this closes the system and shows by experiment that it is closed.

Honest limits, stated by the authors:  it does not work on the bivalve Corbicula fluminalis, "possibly due to variability in shell ultrastructure";  and a refractory bound fraction persists which "has never been satisfactorily explained" (§4.3), which is why "very few studies report true equilibrium D/L values of 1.0."

A Chronological Framework for the British Quaternary Based on Bithynia Opercula

Penkman, K. E. H., R. C. Preece, D. R. Bridgland, D. H. Keen, T. Meijer, S. A. Parfitt, T. S. White and M. J. Collins.  Nature 476(7361):446-449  (2011).

doi:10.1038/nature10305 · PMC3162487 · route that worked: curl https://europepmc.org/articles/PMC3162487?pdf=render (Europe PMC author manuscript, not the published typesetting — page numbers below are manuscript pages)

topic: intracrystalline camp: mainstream type: measurement access: author-manuscript system: closed direction: undercuts

Key figures: 470 opercula from 74 sites spanning the whole Quaternary, ranked by an Intra-crystalline Protein Decomposition index built from Asx, Glx, Ser, Ala, Val and serine dehydration.

Validated against four independent orderings that agree with it:  British interglacial stratotypes;  Thames river terrace elevation;  the Mimomys savini → Arvicola water-vole turnover and the mutually exclusive Corbicula/Hippopotamus pair;  and radiocarbon, which it overturned at Isleworth ("Radiocarbon therefore provides only a minimum age for the Isleworth deposits", manuscript p.3).

The qualification that matters, in the authors' own words (manuscript p.2):  "Sites with independent geochronology can be used to calibrate IcPD results but, as only 7 of our pre-Holocene sites have associated dates, we have not done this here."  This is a relative ranking tied to the marine isotope stages, not an independent absolute chronometer.  It still assumes "that similarly small thermal gradients existed during past interglacials, when most of the racemization would have occurred" (p.2) — the same temperature assumption that sank bone AAR, applied where the authors argue it is small.  And it works on calcite, not bone, so it rehabilitates none of the old bone dates.

Protein survival limits

Preservation of Key Biomolecules in the Fossil Record

Bada, Jeffrey L., Xueyun S. Wang and Healy Hamilton.  Philosophical Transactions of the Royal Society B 354(1379):77-87  (1999).

doi:10.1098/rstb.1999.0361 · PMC1692449 · route that worked: curl https://europepmc.org/articles/PMC1692449?pdf=render.  PDF page N = printed page 76 + N, anchored on the running heads at PDF pages 1 and 10.

topic: protein-survival camp: mainstream type: measurement access: OA system: open direction: supports

OCR trap:  the scan's text layer renders "<" as the digit "5".  "55^10 million years" is "<5-10 million years";  "51 million years" is "<1 million years".  Correct before quoting.

Key figures: proteins nearly completely hydrolysed in ~10⁶ yr on the ocean floor and ~10⁵ yr in surface environments;  little intact collagen after only 1-3 × 10⁴ yr (p.77);  all amino acids totally racemized in <5-10 Myr in cold environments and <1 Myr in temperate regions (pp.80-81);  complete racemization of Asp, Ala and Val at 5 °C in <10 Myr, possibly >50 Myr at subfreezing temperatures where the system behaves as if anhydrous (p.83).

Bada measured Tyrannosaurus bone from Montana and Edmontosaurus bone from the North Slope of Alaska, and found "only trace amounts, if any, of their original amino acids... Any endogenous amino acids that are present have undergone extensive diagenesis as evidenced by the presence of highly racemized amino acids" (p.83).  He also found that amber-entombed insects "contain well-preserved unracemized amino acids, apparently because of the anhydrous nature of the amber matrix" (p.77).

Tagged supports because the survival ceilings it publishes are the whole of the strong young-earth argument, stated by a mainstream chemist from his own data.  But note that the dinosaur result cuts the other way:  Bada's dinosaur amino acids were highly racemized, which is what deep time predicts, not what a 4,500-year-old fossil would show.

Protein Sequences Bound to Mineral Surfaces Persist into Deep Time

Demarchi, Beatrice, et al. (32 authors, incl. Penkman and Collins).  eLife 5:e17092  (27 September 2016).  CC-BY.

doi:10.7554/eLife.17092 · PMC5039028 · route that worked: curl https://cdn.elifesciences.org/articles/17092/elife-17092-v1.pdf

topic: protein-survival camp: mainstream type: measurement access: OA system: closed direction: mixed

Key figures: peptide sequences recovered from ostrich eggshell from Laetoli (3.8 Ma) and Olduvai Gorge (1.3 Ma);  thermal ages (Table 1, p.5) Elands Bay Cave 0.5-45 ka@10 °C, Pinnacle Point 120-470, Wonderwerk ~3,600, Olduvai ~16,300, Laetoli 8,900-20,400;  "50 times older than any previously authenticated sequence (equivalent to ~16 Ma at a constant 10 °C)" (abstract).

The most important single source for the honest version of the young-earth argument, because it does two opposite things in one paper.

It concedes the tension in print (p.2):  "Morphological..., immunological... and spectroscopic... evidence of preserved tissues in dinosaurs and other fossils seems to be inconsistent with the observed levels of hydrolysis, dehydration and racemization... in intracrystalline proteins from the fossil mollusc shell and eggshell."

And it explains a real mechanism:  molecular dynamics on struthiocalcin-1 and -2 predicted which domain binds most strongly to the calcite surface, and that is the domain that survived.  Mineral binding is not a hand-wave here;  it made a testable prediction that held.

The detail nobody should drop: the surviving Laetoli peptides are racemized.  Figure 2 caption, p.4:  "The average hydropathicity of the peptides identified remains stable up to Val D/Ls ~1. Note that Val D/Ls > 1.0 are unexpected."  Valine is the slowest-racemizing amino acid in routine use;  D/L ≈ 1 is full racemization.  So a short, tightly mineral-bound sequence can survive to ~16 Ma@10 °C while its amino acids are racemic.  "Racemized" and "no sequence information" are not the same claim.

The young-earth arguments

The Amino Acid Racemization Dating Method

Gish, Duane T.  Institute for Creation Research, published 1 May 1975.

https://www.icr.org/article/amino-acid-racemization-dating-method

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

The founding creationist critique, written nine years before accelerator ¹⁴C reversed Bada's dates, and it holds up better than most 1975 creationist geochronology.  "The study with bone indicated that an uncertainty of ±2° would yield an age with an error of ±50%."  Concludes that AAR ages "are unreliable and, with few exceptions, are much older than the real ages."

The verdict was vindicated;  the mechanism was wrong.  Gish argued that pH, not temperature, dominates racemization in fossils.  Bada 1985 p.249 reports the direct test:  in heated modern bone, between pH 3 and 8, "racemization rates are not affected by pH", because "the bone minerals effectively buffer the system."  Showing a skeptical reader that this article can tell the difference between a right conclusion and a right argument is worth more than the citation itself.

Gish also relays, through Bender 1974, that a supposedly 25,000-year-old La Brea sabre-tooth bone showed racemization "hardly exceeding that of modern fresh bone."  Neither Bender 1974 nor Bada's reply was obtained.  Do not print that quotation without the originals.  And note that asphalt, like amber, is one of the two environments where the mainstream model itself predicts low D/L at old ages.

Racemization of Amino Acids under Natural Conditions, parts 1-5

Truman, Royal.  Journal of Creation 36(1):114-121, 36(2):72-80, 36(2):81-89, 36(3):74-81 (2022) and 37(1):62-72 (April 2023).  Part 5 posted at creation.com 31 May 2024.

https://creation.com/racemization-of-amino-acids-5

topic: creationist-argument camp: creationist type: model access: OA system: n/a direction: mixed

Parts 1-4 are about homochirality and abiogenesis and belong to the Berean abiogenesis article, not this one.  Part 5 is the fullest published creationist treatment of AAR as a dating method, and it contains both young-earth arguments at once, which is exactly why it must be handled carefully.

Its critical half is largely sound and well sourced:  it walks through the Californian episode from Bada 1985's own tables, notes the leaching and N-terminal effects, quotes Collins 1999's "the pattern and rates are unpredictable" accurately, and observes something real — that across Bada's Table 5 the older the assigned age, the lower the fitted k.

Its constructive half then recalibrates the same data to young ages:  "We show that dates based on proportion of amino acid racemization can be reliably recalibrated to predict dates which do not exceed the age of the Genesis Flood."  Picking the Yuha specimen as calibrant gives k = 1.95 × 10⁻⁴ yr⁻¹, from which "most of these American Indians lived in the Christian era";  importing Steen et al. 2013's k = 0.0116 yr⁻¹ for alanine, measured at 49.5 °C, gives "only about 150 years... for the Pleistocene fossils to attain a D/L = 0.95 for alanine and not a million years."

Tagged mixed because the two halves contradict each other in the same paper.  A method whose rate constants Truman calls unpredictable cannot then be recalibrated to yield reliable young dates.  And the 49.5 °C import is the same free-temperature-parameter move that made Bada wrong in 1974;  it does not become sound because the error now points the other way.  Truman is candid that it is a supposition — "49.5 °C might seem high, but this would be the effective and not average temperature" — which makes the problem visible rather than hidden.

Citation defect to route around: his reference 15 gives Bada 1985 as Ann. Rev. Earth Planet. Sci. 1:241-268.  It is volume 13.  Cite Bada directly.

Radiocarbon in Dinosaur and Other Fossils

Thomas, Brian, and Vance Nelson.  Creation Research Society Quarterly 51(4):299-311  (Spring 2015).

https://media2.kgov.com/files/CRSQ-2015-thomas-nelson-14c-in-dino-fossils.pdf

topic: creationist-argument camp: creationist type: measurement access: OA system: n/a direction: background

Obtained, read, and deliberately not used.  A full-text search returns zero hits for "racemi" — it is a radiocarbon paper with no racemization content.  It belongs to the dinosaur-soft-tissue article, whose memory file already records the standing decision to reject ¹⁴C-on-dinosaur-bone arguments on provenance and contamination grounds.  Recorded here so the next agent does not fetch it again expecting racemization data.

The Protsch fraud, and the racemization ages that tracked it

History of Modern Man Unravels as German Scholar Is Exposed as Fraud

Harding, Luke.  The Guardian, 19 February 2005.

https://www.theguardian.com/science/2005/feb/19/science.sciencenews · route that worked: curl with a browser user-agent, 283 KB of HTML, tags stripped locally.  No page-summarising tool used.

topic: history camp: unaffiliated type: popular access: OA system: n/a direction: mixed

Contemporaneous report of the University of Frankfurt's own finding — not an allegation, a finding.  It names the commission chair, Ulrich Brandt, quotes him on "10 sittings with 12 witnesses," names Oxford University's radiocarbon dating unit as the authority that redated the specimens, and prints the redates: Hahnhöfersand 7,500 years, Binshof-Speyer 1,300 BC against a claimed 21,300 years, Paderborn-Sande died in 1750 against a claimed 27,400.

A newspaper is the weakest kind of source this article uses, and it is used because it is contemporaneous and because it reports an institutional finding.  The peer-reviewed record of the redating programme is Street, Terberger & Orschiedt, "A critical review of the German Paleolithic hominin record," Journal of Human Evolution 51(6):551-579 (2006), doi:10.1016/j.jhevol.2006.04.014 — paywalled and not obtained;  nothing rests on it, and it is named so a reader knows where the technical record is.  The Frankfurt commission's own report was also not obtained.

Upper Paleolithic Blues: Consequences of Recent Dating Fiasco on Human Evolutionary Prehistory

Line, Peter.  Creation Ministries International;  dated 13 April 2005 in its own text, posted 9 February 2006.

https://creation.com/en/articles/upper-paleolithic-blues · route that worked: plain curl, tags stripped locally.

topic: creationist-argument camp: creationist type: review access: OA system: n/a direction: mixed

Attribution note: frequently credited to John Woodmorappe.  The byline and the "About the author" block on the page both give Peter Line, and that is how the article cites it.

Cited for one thing Harding does not cover, and it is the thing this article needs:  Protsch published racemization ages for the same three specimens, and they agree with his own radiocarbon ages to within about five per cent — Hahnöfersand 36,000 against 36,300, Paderborn 26,000 against 27,400, Binshof 22,000 against 21,300.  Line's own word is "supposedly."  His sources for the racemization figures are Protsch's published determinations as reported by Fred H. Smith in The Origins of Modern Humans (1984), pp.144, 179, and Winfried Henke, Zeitschrift für Morphologie und Anthropologie 70:275 (1980).  Neither of those was obtained, so the racemization column in the article's table is carried at one remove, and the article says so.

Credit where due.  Line caught this in 2005, in print, with the numbers, and drew a restrained conclusion.  He is graded better here than Gish is.

The two best young-earth papers, both missed on the first pass

Amino Acid Racemization in Marine Sediments

Helmick, Larry S.  Creation Research Society Quarterly 13(1):14-22  (June 1976).

https://crsq.creationresearch.org/329/1/Amino%20Acid%20Racemization%20in%20Marine%20Sediments.pdf · record page https://crsq.creationresearch.org/id/eprint/329/ · route: curl, then pdftotext -layout

topic: creationist-argument camp: creationist type: model access: OA system: open (sediment) direction: mixed

Locator trap: the EPrints record page prints "13 (1): 3" and that last figure is the article's position in the issue, not its first page.  Real pages 14-22, pinned from the alternating running heads.  PDF page N = printed page 13 + N.

Not the argument §3(b) was aimed at.  Helmick, then Professor of Chemistry at Cedarville College, does not claim racemization gives young ages.  He claims a shape: D/L against depth in a deep-sea core should show a slope discontinuity at the Flood boundary, and he says it is already visible in core V23-110 (p.20).  A kink in a curve is immune to any uncertainty in k, which is why the article's answer to Truman does not touch it.

Answered in the article on three grounds.  (i) His Figure 4(A) has the conventional model predicting "nearly linear plots of racemization versus age" (p.19), and the reversible first-order rate law predicts no such thing — it predicts a tanh that flattens toward equilibrium on its own.  (ii) The one core he rests on is a core he himself reports two mainstream groups reading in opposite directions: "Wehmiller and Hare have reported that racemization in the free amino acid fraction of core V23-110 decreases with depth, rather than increases.  Yet Kvenvolden et al. reported increasing racemization with depth for the same core" (p.15).  (iii) Both models predict flattening, so flattening cannot discriminate;  the conventional model additionally says at what value and roughly at what depth, and Helmick's boundary is a free parameter.

His own conclusion (p.21) is that meaningful sediment ages cannot be got from a total-amino-acid D/L and a first-order rate constant — the same verdict Bada, Collins and this article reach.

Amino Acid Dating

Brown, R. H.  Origins (Geoscience Research Institute) 12(1):8-25  (1985).

https://www.grisda.org/assets/public/publications/origins/12008.pdf · record page https://www.grisda.org/origins-12008 · route: curl, then pdftotext -layout.  PDF page N = printed page N + 7, anchored at both ends against the running heads.

topic: creationist-argument camp: creationist type: compilation access: OA system: n/a direction: mixed

The best young-earth paper on this subject, and the article says so.  Two arguments.

One, protein survival, in 1985: "Since detectable levels of many amino acids are expected to survive only a few million years, at best, these observations are an enigma" (p.9), naming Silurian graptolites at 400-430 Ma and Jurassic shells at 135-180 Ma.  That is this article's §3(a), two decades before Schweitzer.

Two, the falling rate constant.  Rate constants collected from nineteen published sources, plotted against assigned fossil age, fall 700-fold (his Figure 3, aspartic acid) and about 2,000-fold (Figure 4, isoleucine) across an axis running 100 years to 10 Myr (pp.16, 20).  His inversion: hold k constant and the ages collapse.  Table 2 (p.21) reassigns 40,000 → 5,000-6,000, 100,000 → 11,000-14,000, 350,000 → 18,000, 1,000,000 → 8,000-14,000.

Why it is tagged mixed and not supports.  The apparent rate constant is f(D/L)/t and D/L has a ceiling, so once a sample saturates the fitted constant must fall in inverse proportion to the assumed age.  Over Brown's own 3,000-to-2,000,000-year interval that artefact is 667-fold and he measures 160-fold;  over the full Figure 4 axis it is 10⁵-fold and he reports 2,000.  The trend is shallower than the artefact, so nothing is left for a revised chronology to explain.  Collins 1999 later supplied the mechanism Brown said the field was asserting on faith.

Two things to Brown's credit, both worth more than the argument.  He tested the obvious mainstream explanation himself and killed it — a 160-fold reduction would need an effective average storage temperature of −19 °C (p.17) — and he refused to bank his own Table 2: "presented here for their possible interest, without any claim as to their significance" (p.21).  His table also tops out at 18,000 years, which is not a Flood chronology, and he never says it is.

The reply to Penkman 2011

A Snail's Tale of the Past

Mitchell, Elizabeth.  News to Know, Answers in Genesis, 13 August 2011.

https://answersingenesis.org/environmental-science/ice-age/protein-degradation-purported-peer-into-past/ · route that worked: plain curl, tags stripped locally.

topic: creationist-argument camp: creationist type: popular access: OA system: closed direction: mixed

This entry exists because the article's first draft said no creationist had engaged Penkman 2011.  That was false, and the article now says so in its own voice.

Two objections.  Circular calibration: "the protein-based chronometer is calibrated according to uniformitarian assumptions about earth's icy past.  In other words, each degradation ratio corresponds to a particular layer, and the dates claimed for that layer are then assigned to the degradation ratio."  Shared temperature sensitivity: "Since oxygen ratios and amino acid racemization are both temperature sensitive, they correspond and vary according to the seasonal and climatic changes they were exposed to.  But neither tells us anything about the duration of those variations."

The first is granted — the article already concedes it, and Penkman's own paper declines to convert IcPD into years.  The second fails, because racemization is monotonic and irreversible while δ¹⁸O oscillates, and because three of the paper's four validation orderings (terrace elevation, the Mimomys/Arvicola turnover, the Hippopotamus/Corbicula split) are not temperature records at all.  The Hippopotamus/Corbicula pair is the sharpest test: two equally warm interglacial faunas, different protein states, in stratigraphic order.

Note on her sourcing: her stated news source is the ScienceDaily write-up, so the Penkman quotations in her piece are press-release quotations rather than sentences from Nature.  Her objection is aimed at what the paper claims, and is answered on that basis.

Not obtained

Full routes tried are recorded in research/_brief.md § 8.  In brief:

• Bada, Schroeder & Carter 1974, Science 184:791-793 — science.org 403; Semantic Scholar reports the paper and its abstract as elided by the publisher; the AAAS registered-reader account opens only publisher-flagged free articles. Its figures are recoverable from Bada 1985 p.259 and Taylor 2009 p.183, both obtained.
• Taylor et al. 1985, American Antiquity 50:136-140 — Cambridge Core abstract only. Superseded for this purpose by Taylor 2009, which is free.
• Bada 1985, American Antiquity 50:645-647 (his printed reply to Taylor) — paywalled. The Annual Review paper obtained above says the same things at greater length with the arithmetic attached.
• Bada, Gillespie, Gowlett & Hedges 1984, Nature 312:442-444 — paywalled; results reproduced in Bada 1985 Table 5.
• Hare & Abelson 1968, Carnegie Inst. Washington Year Book 66:526-528 — not attempted. Likely reachable on archive.org.
• Bender 1974 and Bada's reply — not obtained; quoted here only through Gish, and flagged as unverified.
• Street, Terberger & Orschiedt 2006, J. Human Evolution 51(6):551-579 — the peer-reviewed record of the Protsch redating programme. Paywalled; the DOI was confirmed through Crossref and nothing else was attempted. Harding 2005 carries the facts the article needs.
• The University of Frankfurt commission report on Protsch — not obtained. Harding 2005 reports the university's announcement, which is what the article cites.
• Fred H. Smith, The Origins of Modern Humans (1984), pp.144, 179, and Winfried Henke, Zeitschrift für Morphologie und Anthropologie 70:275 (1980) — the published sources for Protsch's racemization ages, reached only through Peter Line. Not obtained. Worth one archive.org attempt by whoever revises this next; it would move the racemization column of the article's table from second-hand to first-hand.
• Mats Molén, "The Ice Age: It Really Was Short," Proceedings of the Sixth ICC (2008), p.340 — the only ICC statement of the racemization-gives-young-ages argument, and it relays Brown 1985. Two fetch routes for the PDF failed; Brown was obtained directly instead, which is the better source since Molén is only quoting him.

Disposition: what the article did with each entry

Recorded 30 August 2026, when the article was written.  Every entry above is accounted for here, so nothing sits in this catalogue with an unknown status.

One claim that was not in this catalogue remains in quarantine.md rather than in the article: Jay Wile's blog claim that a racemized protein can retain structure.  A second, the Reiner Protsch fabrication finding, was quarantined on the morning of 30 August 2026 and released the same day once Harding 2005 was obtained;  quarantine.md records what changed and what is still missing.