Cast, Not Carved · source record · report

Tiahuanaco monuments (Tiwanaku / Pumapunku) in Bolivia are made of geopolymer artificial stones created 1400 years ago (Archaeological Paper #K-eng)

Joseph Davidovits; Luis Huaman; Ralph Davidovits · 2019

AI-verified citationSRC-DAVIDOVITS-2019

identifier / locator: doi:10.13140/RG.2.2.31223.16800
url: https://www.geopolymer.org/wp-content/uploads/TIWANAKU-PUMAPUNKU.pdf
verification note: text retrieved and shown to the drafter on 2026-09-09 (run 2026-09-09-draft-megalithic-casting-033429); passages checked by the verify verb
reliability notes: Proponent source: self-published transcript of a Geopolymer Camp 2018 conference talk, hosted by the Geopolymer Institute; not peer reviewed.
Same authors and same sample series (PP1, PP2, PP4, PP5) as SRC-DAVIDOVITS-2019-ML and SRC-DAVIDOVITS-2019-CI; not an independent line of evidence.
Useful chiefly as the authors' own fuller account of sampling context, methods and admitted limitations; contains quotations of third parties (Protzen & Nair, Cieza de León via Markham, Minkes) that enter here only second-hand.
The text itself notes the research received no external funding and that SEM data were collected at Pyromeral Systems SA.

Evidence drawn from this source

Qualifies· moderateGEO-E057

Andesite sample PP1 was chosen from loose debris outside the protected monument area, by its flat surface

what the source states: The source states that numerous andesite fragments lie scattered and abandoned on the site: "They are outside the protected monument area." and that by "carefully choosing this debris consisting in fact of pieces" of monumental stones with the characteristically flat surface the authors obtained their samples; PP1 A and B came from the fresh broken part of a fragment on the ground (Fig. 21), PP2 from the corner of a broken door fragment, PP5 from the surface of a flat slab.
what we infer: Mine: the andesite result is about a loose fragment attributed to the monument by appearance, with no object number, excavation context or documented refit; its transfer to the H-blocks (as in the IMG-GEO-P04 caption) is an attribution, not an observation. This narrows GEO-C004 and GEO-C021 without denying either.
limitations: The peer-reviewed statement of the same context (Ceramics International, 'Andesite samples' section) was not shown; this is the authors' own longer account.
'Outside the protected area' does not by itself exclude that the fragments are from architectural blocks.

Joseph Davidovits (2019)AI-verified citationGEO-C004 GEO-C021

Supports· weakGEO-E058

An interior subsample (PP1C) is reported to show the same carbon- and nitrogen-bearing amorphous matter beneath feldspar grains

what the source states: Anticipating a surface-contamination objection to the organic matter found in a surface hole of PP1, the authors state "we looked inside PP1A by cutting from its interior a smaller sample labeled PP1C" and report several interior spots with the same EDS spectrum (C, N, Na, Mg, Al, Si, P, S, Cl, K, Ca), including a dark sheet lying underneath two plagioclase crystals (Fig. 27).
what we infer: Mine: an interior occurrence makes simple modern surface dirt an incomplete explanation and is the strongest part of the andesite result. It remains one fragment of insecure provenance, analysed by the proponents with no natural andesite control, and EDS cannot characterise the organic compound.
limitations: Same team, same fragment as GEO-E007; not independent.
EDS is elemental only; no molecular identification of the 'organic matter'.
Sample provenance as the source states it.

Joseph Davidovits (2019)AI-verified citationGEO-C004

Qualifies· moderateGEO-E059

Nitrogen only semi-quantitative; authors cannot say whether the organic matter is unreacted guano or the binder

what the source states: The source states that nitrogen 'cannot be determined by simple EDS' and that its quantitative analysis "cannot be carried out with our present equipment"; that the EDS of Ilo guano is similar to that of the monument organic matter; and that "we do not know whether the PP4 organic matter is the remaining part of unreacted guano" or the spectrum of the organo-mineral binder itself (the text says PP4 here, apparently meaning the andesite sample).
what we infer: Mine: the guano-hardener identification rests on elemental similarity by EDS and is, by the authors' own statement, unresolved between residue and binder. This limits both the andesite observation (GEO-C004) and the Andean chemistry claim (GEO-C580) to a hypothesis.
limitations: The 'PP4' label in the source at this point conflicts with the andesite sample name PP1; read as a slip, but recorded as written.

Joseph Davidovits (2019)AI-verified citationGEO-C004 GEO-C580

Qualifies· moderateGEO-E060

No geological andesite was compared with monument andesite in the 2019 study

what the source states: The source states that the 1970s Bolivian study did no petrography on the andesite, that Janusek et al. 2013 confirmed Khapia as the principal source by portable XRF on boulders, and that consequently "we do not compare geological andesite and monument stone" as was done for sandstone: 'In the absence of a geological study, we did not know where to look.'
what we infer: Mine: the andesite 'unicum' claim has no natural comparator at all in the published work. Volcanic rocks can host amorphous glassy phases; without a Khapia control the organic/amorphous features cannot be shown to be absent from the parent rock.
limitations: Applies to the 2019 work; the 2020 paper (GEO-E035) still presents no andesite comparison.

Joseph Davidovits (2019)AI-verified citationGEO-C004 GEO-C021

Context· weakGEO-E061

Stübel & Uhle (1892) already noted 'round nests of amorphous substance' in a thin section of Tiwanaku monument andesite

what the source states: The source reports that its thin section of PP2 shows black areas of amorphous substance across the field, and notes that the nineteenth-century travellers' thin section of a different Tiwanaku andesite recorded, in German, "Round nests (pockets) of amorphous substance, in the middle" light brown, fading to the edges, noticed occasionally.
what we infer: Mine: an 1892 observation of amorphous pockets in monument andesite predates the geopolymer hypothesis and was made by observers with no stake in it; it establishes that amorphous matter is a recurring feature of this stone but says nothing about whether it is organic or natural volcanic glass. Background only.
limitations: Stübel & Uhle quoted second-hand and in the proponents' translation.

Joseph Davidovits (2019)AI-verified citationGEO-C004

Supports· weakGEO-E062

Surface bubbles and sharp interior angles offered as wet-sand-molding signatures; Protzen & Nair quoted on hammerstones

what the source states: The source quotes Protzen & Nair (1997) that a hammerstone point "could never produce the crisp right interior angles" of Tiwanaku stonework and that the builders' tools remain unknown, and states that the H-blocks show a dense skin and "semi-spherical air bubbles which had been trapped against the mold", read as evidence of pounding semi-dried geopolymer mortar in a mould or carving a preform before hardening.
what we infer: Mine: the Protzen quotation is a conventional scholar's statement that the tooling is unexplained, not an endorsement of casting; the bubble reading is unmeasured surface morphology of the kind GEO-C594 warns may reflect weathering or intervention. Weightless as evidence of casting; recorded as the proponents' argument.
limitations: Protzen & Nair 1997 quoted second-hand.
No measurement or comparison of the 'bubbles' against natural vesicles in andesite.

Joseph Davidovits (2019)AI-verified citationGEO-C021

Supports· weakGEO-E063

Guano trade from Ilo to Tiwanaku via the Moquegua valley, as reported by Minkes 2005 and read by the proponents as exceeding agricultural need

what the source states: Citing Minkes (2005), the source states that llama caravans carried "the guano gathered in large quantities at Punta Coles, Ilo" up to Tiwanaku through the Moquegua valley, that this trade 'appears to have been intensified during the Tiwanaku / Pumapunku construction', and that because the raised-field system supplied fertilizer on site "They did not need the guano, because they produced on site their own fertilizer."
what we infer: Mine: the trade route and its intensification are Minkes' (second-hand here); the claim that quantities exceeded agricultural need is the proponents' assertion without figures. Supports the descriptive part of GEO-C581 weakly; the 'did not need it' inference is unquantified.
limitations: Minkes 2005 not read; no quantities of guano traded are given.
'Intensified during construction' is undated in the source.

Joseph Davidovits (2019)AI-verified citationGEO-C581

Supports· weakGEO-E064

Plant acids do not disaggregate andesite; the acid-medium andesite binder is said to be replicated in the laboratory with modern chemicals

what the source states: The source states that carboxylic acids (acetic, oxalic, citric) work on limestone — any stone containing limestone "will be disaggregated but not volcanic andesite" — so the chemistry can only make a binder to agglomerate unconsolidated material; that earlier attempts could soften limestone but not re-harden it; and that the acidic-medium method with guano 'has been successfully replicated in our laboratory with modern chemicals' to test the mechanism.
what we infer: Mine: consistent with GEO-C580's three-stage description, but the replication is asserted without recipe, data or product characterisation, and used modern reagents rather than plant extracts and guano. Feasibility of the mechanism is claimed, not shown.
limitations: No experimental data presented for the replication.
Modern chemicals, not the proposed ancient inputs.
Second reader (claude-sonnet-5, 2026-09-09) disputes the stated direction: The quoted passages are accurately located at p.16 (\u00a72.3.1-2.3.2) and p.18 (\u00a73 Conclusion) and are quoted in context, and the sourceStatement fairly summarizes them without overreach. However, the source explicitly says the acids cannot disaggregate andesite (only limestone), that early attempts to re-harden softened stone failed, and that the acidic-medium mechanism was only replicated with modern chemicals rather than the plant/guano inputs claimed for antiquity \u2014 this qualifies or undermines the pre-industrial feasibility asserted in GEO-C580 rather than supporting it, so the stated 'supports' direction is wrong (dissent recorded, not a rejection).

Joseph Davidovits (2019)AI-verified citationGEO-C580

Supports· weakGEO-E065

Cieza de León (via Markham 1864) on Tiwanaku: pre-Inca attribution and bewilderment about tools, as quoted by the proponents

what the source states: The source quotes Markham's translation of Cieza de León (visit 1549): 'For myself I fail to understand with what instruments or tools it can have been done', that in all the district 'there are no quarries whence the numerous stones can have been brought', and that the natives laughed at the question, "affirming that they were made before the Incas ever reigned", but could not say who made them.
what we infer: Mine: the quoted passage supports the pre-Inca oral tradition and the chronicler's puzzlement in GEO-C585; it does not contain the 'single night' or 'bearded men' elements, which must be sourced separately. Second-hand and a nineteenth-century translation.
limitations: Markham's translation quoted by proponents; the Spanish original not consulted.
Supports only part of a compound claim.

Joseph Davidovits (2019)AI-verified citationGEO-C585

Context· weakGEO-E066

Radiocarbon dating of the andesite organic matter announced as the next step (2019); no result located

what the source states: The source states that because organic matter was found inside the andesite the team will be able to carry out Carbon-14 dating, and that 'the next step of our study will be to "gather enough sample in order to implement Carbon-14 dating" and provide the exact age of the monuments.'
what we infer: Mine: the report searched for and did not find a published 14C result in the following years; that is a retrieval outcome, not proof of absence. If run and published, a date near AD 600 would bear on GEO-C004 and GEO-C021 strongly; a modern date would point to contamination. Background until then.
limitations: Announced intention only.

Joseph Davidovits (2019)AI-verified citationGEO-C004