Dear Dr. Wenzel,

I have no direct information but can give an (approximate!) answer based on my experience. As fish vertebra are composed of carbonate-hydroxyapatite (same as bones), they should be affected to relatively fast weathering in open-air sites, in particular in an acid, oxidising environment – the one you expect in sandy soils. Nonetheless, if post-depositional burial is fast and the sediment sealing the features thick enough to avoid surface weathering (which seems to be the case of your profile, as the pit has been buried under almost 1 m-thick sediment), chemical weathering of bones and related materials (as fish vertebra) can be much lower than expected.

If the profile is still exposed, you could perform soil routine analyses (grain size, pH, calcium carbonate content etc) or micromorphological observation in order to evaluate soil formation processes and assess their impact on the Mesolithic archaeological record.

In a nutshell: yes, they could be preserved, under certain conditions.

Hope this helps.

Regards,

Diego E. Angelucci

Dear Dr. Angelucci,

thank you very much for your answer. For me the statement is helpful that the fish remains would need a to be buried relatively quickly in order to get a chance of post-depositional preservation.

It would require new excavations to examine similar features in the vicinity. But if I would get again the chance to dig a Mesolithic site (which is more than unlikely) I would include pedological investigations in the research desgin. The same with palaeobotanical studies. In 2000/2001 I took some soil samples and gave them to scientists, but because of the difficult times studies have never been completed.

Best regards,

Stefan Wenzel

If the sand is dry and hot quite a long time - as the sand is sterile. Hence the amazing state of Egyptian Mummies.

Thank you for your answer. This may apply to the dessert conditions. But the site is in the North European Lowlands, on the edge of a former watercourse, which was transfomed in a lake and later in a peat bog.

Dear Stefan,

many thanks for sharing the great images! As Diego has already alluded to, I suspect it is a matter of the speed of material deposition above the remains, and pH. If deposition was relatively quick it's possible that the peat has also acted as a buffer against degradation...

From memory there are several Mesolithic/Neolithic sites in the Netherlands and Belgium that contain fish remains from sandy soils.

On another note, how many of the fish vertebra were calcined? (At Star Carr numerous remains were preserved within the structure because they had been calcined otherwise I don't think we would have recovered any at all).

Lastly, based on your photograph it is interesting that the majority of the remains are eel and salmonids because these two species are often cited as not preserving so well due to their fatty nature!

All the best,

Harry

Dear Harry,

thanks for your advice. I will have to look on other sites and hopefully find distribution maps of artefacts and bones within "mesolithic pits" and their surroundings.

Unfortunately I have not noted the ratio of burnt bones, while I well distinguished heated and not heated flint. When sorting and cataloging the finds from the excavation, I tried to separate fish remains and remains from pond tortoise from the rest of the bones, because of the fragility of the fish bones and because they should be analysed by different persons. I think I had asked Dirk Heinrich from Kiel to determine the fish bones. But he was never given the fish remains, because the inventory was never completed. The finds are now in the depot of the monuments office in Wünstorf, but a small portion of them is unsorted and not catalogued. And I'm not sure if my separation of the fish remains would have been realy helpful. A specialist analysing the fish bones would only get, what I thought to be a fish bone. I skeletonized a pike in order to recognise not only the vertebra, but my work was certainly far from perfection.

In any case, your overview over the compostion of the sample is helpful, as it points rather to a quick deposition of the fish bones.

All the best,

Stefan

Dear Stefan,

I have examples of fish vertebrae surviving in sandy soils at least 4000 years form Northern Norway -see :

• Technical Report InSituFarms. Archaeological Deposits in a Changing Climate. ...

• Article Research and Monitoring on Conservation State and Preservati...

• All the best, Vibeke

Dear Vibke,

thank you for pointing to this fascinating research. Like in the answer of Diego E. Angelucci it becomes clear that several parameters in combination have influence on the preservation of bones, and that moisture, temperature and soil acidity play a role. Which makes it difficult to evaluate the condition of burying if they have not recorded at excavation.

In the lower link you refer to:

https://niku.no/en/archaeology/environmental_monitoring/archaeological_deposits_in_a_changing_climate_in_situ_preservation_of_farm_mounds/

Has this content been moved? In case it has a new adress, I would be grateful if you could announce the current link.

All the best,

Stefan

https://www.forskningsradet.no/prosjektbanken/#/project/NFR/212900Dear Stefan,

our website has been updated - and unfortunately left out some links... -check https://niku.no/en/ansatte/vibeke-vandrup-martens/

and

https://www.forskningsradet.no/prosjektbanken/#/project/NFR/212900

All the best,

Vibeke

Dear Vibeke,

many thanks for the links.

All the best,

Stefan

Dear Stefan,

personally I doubt the interpretation of Mesolithic hearth pits as ant nests published by Crombé et al. in at least two papers. I have had a look at samples from some of these pits and they contain quite a lot of Pinus sylvestris charcoal (sometimes quite a lot of big fragments not very suitable to be transported by ants) but f.e. no fragments of pine needles and nearly no small twigs and branches, which should at least be preserved sometimes if these structures had been ant nests. Nevertheless, at most places there are also silex artefacts and the hearth pits are clustered in lines...

I have never seen ant nest arranged in this specific form.

So far I know these boreal and early Atlantic hearth pits of northwestern Lowwer Saxony and the Netherlands have never delivered any fish bones - at least I haven't seen any.

Some more paper on hearth pits, you may already know :

Article Gruben, Gruben und noch mehr Gruben. Die mesolithische Funds...

Article Fire in a hole! First results of the Oldenburg-Eversten exca...

So I guess your Friesack pits are maybe different to these hearth pits like Oldenburg-Eversten.

KInd regards

Julian

Dear Julian,

many thanks for your contribution to the discussion and for pointing me to the articles on Oldenburg-Eversten. The pit figured in the first article you have linked is very impressive. It has absolutely straight and clear borders. A collapsed ant nest should have more diffuse boundaries.

Thank you also for pointing towards the spatial distribution of those pits and the composition of Pinus sylvestris remains.

For the pits in Friesack (not the water holes excavated there by Bernhard Gramsch) the evidence is ambigous. On one hand, the pits are still in the size range described by Crombé and colleagues, they are on the dryest part of the hill, they contain charcoal and burnt and unburnt objects, and they have diffuse borders (because of biturbation). They differ von ant nests in respect of their content, which is rather indicative for a quick filling. Having been sediment traps, they contain more burnt and unburnt flint than their surrounding, but the ratio of heated flint is lower than in their vicinity. This is not consistend with former ant nests filles with material after forest fires (which one would hardly expect because of the setting of the site). The preservation of the fish remains and of parts of a carapax of a pond tortoise speak tentatively also for early burial. Two of the pits contain chips of quartz and one a piece of amber, materials not found elsewhere during the excavation of 2000/2001. And one may take in account, that the site was heavily eroded (leading to the sandy subaquatic bank sediments excavated by Bernhard Gramsch), and therefore the pits were deeper in Mesolithic times).

However, some Mesolithic pits may actually be collapsed ant nests. And the discussion opened by Philippe Crombé and colleagues is useful, because it demands finding arguments for an artificial or natural origin of these features, which may reveal interesting insights.

Kind regards,

Stefan

Hi Diego,

fish remains in antarcticornithogenic soils are as old as 7,000-8,000 yrs, few remains are possibly also older (pre dating LGM). Please, contact me in case you need papers on this but they should be available in imy profile.

I further indicate that from Barfield's excavations in Manerba-Sasso, fish vertebrae were found in Eraly Neolithic layers. All the best ciao

Carlo

Dear Diego,

many thanks for your answer and the references. I'll have a look on them.

All the best,

Stefan

Dear Dr. Wenzel,

Here you can find a link to a new open-access volume completely focused on mesolithic pits (Creuser au Mésolithique, Société préhistorique française ).

Maybe you can find something interesting to interprete your features:

http://www.prehistoire.org/515_p_50273/acces-libre-sEance-12-creuser-au-mesolithique-digging-in-the-mesolithic.html

Different pits presented in the volume are very constructed spaces. I agree with Dr. Wiethold when he suggest an anthropgenic origin for your pits, especially regarding to the varibility and the size of artefacts and ecofacts founded, or the sedimentary carachteristics of the pit. But it's a good reflex to always test the natural VS artificial origin of the excavated feature.

How previusly suggested by Dr. Angelucci, if new pits will be founded during future excavations, the best way to understand the nature of these pits is to set up a geaoarchaeological analysis using soil micromorphology and integrate this to the archaeological research.

With all the bests,

Alessandro

Dear Alessandro,

many thanks for your answer, and especially for the link to the BSPF volume, from which I did not know that it is open access. The articles there will be very usful. I agree with your conclusions, particularly that micromorphology can be much of help evaluating the nature of such features.

All the best,

Stefan

Dear Stefan,

I concurr with previous posters that the ant-mound hypothesis is highly unlikely; the evidence presented in the papers is (IMO) very tentative. Moreover there a many properties that point to anthropogenic origins, including spatial distribution, artefact associations and micromorphological properties of the charcoal. Discussions on the potential use of these pits are ongoing, and include food preparation, tar production, charocal production. I hope several ongoing micromorphological studies of myself and others in the Netherlands are going to shed more light on this.

Regarding the preservation of bones: In princple, buried bones will be well-preserverd if the soil is calcareous and/or waterlogged. (see "bone" chapter in https://www.academia.edu/1971368/Degradation_of_archaeological_remains

Well-preserved fish bones are known form many waterlogged Neolithic and Mesolithic - including indeed many from the Netherlands.

The speed of decay is very difficult to predict, however. I am remined of 7000 yr old refuse layers from an early neolithic (LBK) site in well-drained non-calcareous loss, where still some bone fragments were present - although with evidenced for decay:Article Micromorphological study of Early Neolithic (LBK) soil featu...

I hope this helps,

WIth kind regards,

Hans

Dear Hans,

thank you very much for your message and for the references. The handbook on degradation is useful in various aspects and I will pass it to my colleagues. In respect of my question it provides two arguments for a quick burial of the bones:

p 44: "Damage by fungi, plants and insects occurs mainly in an environment where oxygen is available." - In case of the fish vertebra, this may imply that they were not at the surface for long and that the high water level at this site from the Neolithic until the 18th century contributed to their preservation.

p. 44: "Mechanical processes affecting the preservation of bone generally occur when the bone is buried not far below the surface." - The fish bones don't look to have been affected much by mechanical processes ...

The role of chemical weathering is difficult to evaluate for me, because the fish bones are no longer within reach for me. 'Infiltration of humic acids' (p. 45) can indeed have had a positive effect on their preservation.

The results of you micromorphological study on the LBK site are impressive. But this is a chance not used at excavation. Some latex profile soil peels were made, but I would hesitate to sacrifce them.

Kind regards,

Stefan