Most of the analysis of limestone used in ancient construction that I have seen reported and scientifically analysed, Davidovits, or Barsoum et al, DO have marine shells in them.
I noted from just one post in that ATS thread there was a rock section plate which showed none of such.
Where did that analysis come from? EXACTLY?
For completeness , information, and some might be interested I advise I have managed to find a source of the analysis I questioned above. HERE
It is a rather detailed analysis of ten samples taken at Sacsayhuaman. Each is described in detail with photos and the microscope plates (chemical analysis) and more.
I found it very interesting. Several samples have no "organic residue": or marine shells. Others do have such.
Their preliminary conclusions are mixed
The Saksaywaman construction material is evidently represented by the organogenic and fine-grained limestone with no organic residues and with a low amount of their fragments.
ITAG experts suggest that the fine-grained limestone may be an artificial material produced with unknown technologies. This statement is presented in the official summary.
On the other hand, the experts of Fersman Mineralogical Museum in Moscow, of the Geology Department of St-Petersburg State University and of the Department of Geology of Oil and Gas of the South Federal University have expressed their opinion during the private consultations that the mentioned fine-grained limestone is deemed to be a natural formation.
For some reason I am unable to post the photos of sample 6
It might be an optical illusion? But have a look and see if that polygonal block (separated from wall) does not give every appearance of having a thick coat of render (different material on its face)
(Others ought look at the structure of rock to see if they think it is light and porous precipitate)
Also other might like a re- read of This 2011 article posted in articles section of this site.
In discussing the analysis by a University in Holland of the thin layer of vitrification that is present on stones all over Peru including Sacsayhuaman, they come to the conclusion its chemical make up is similar to that of ceramic glaze.
All the ingredients of such can be found readily nearby, including the flux to reduce the necessary temperature for such. Maybe some sort of Fresnel lens or relector dish for sun?.
It strikes me in particular, because I have had some involvement with geopolymer based , spray on decorative concrete.
It requires a final coat of liquid sealant which can give a brilliant glaze ( or duller matt finish if req'd)
So they also seemed to artificially glaze the blocks. Note it will weather off over time so only protected random spots left.