Archaeometry - Science topic

You are right

Patrick Schmidt You can also use spectra of samples following more complex optical models for quantification - you just cannot use the Beer-Lambert law (which is anyway just a sometimes very rough approximation), but have to use wave-optics and dispersion theory...

@ Sandra

... you likely will not find my advice /recommendations supported in any preservationist's or curator's manual, but if I were faced with your problem, I would store the hair specimens (carefully insured against humidity by inclusion of silica-gel desiccation packets) in air-tight glass containers (wide-mouthed Pyrex bottles or jars with clamp-on lids and Viton gaskets / seals), in which the air has been displaced (flushed-out) by argon before sealing. 100% pure argon gas is generally, ubiquitously and cheaply, available (every university will have cylinders of it ... if not readily available on loan from your physical sciences department, then just ask the maintenance department ... it is a common consumable for every modern arc-welder). 

This method has several advantages ... not the least of which is establishing/maintaining the best preservation environment at the least expense ... AND being able to withdraw specimens at intervals for tests in the future with ease and, without affecting (significantly or negatively the preservation of) the remaining bulk.

Additionally, clear/colorless glass containers will provide the most ease /facility /efficiency in storing /monitoring /inventorying the specimens over long periods of time.

The glass containers should be stored in a cool-and-dark place (any light-tight /drawer /cabinet or /closet-shelf in an air-conditioned building would be adequate), but freezing would not be /necessary /advised or /advantageous.

PS - my recommendations are based-upon (adapted from) the method of preservation chosen for what may be the most cherished parchment document in the world ... the Constitution of the United States of America.  It also is likely the best-protected, artifact in the world, having it's own bunker hundreds-of-feet underground into which the document will recede via an automatic elevator to survive any attack, even direct-hits by a nuclear warhead on the surface). Of course, this farthest step would not be necessary for your hair specimens ;) 

Dear Marcus, dear Aaron

so, this was the first approach to get the true values… now we have to go into the details.

First of all we need to talk about what happens in the system X-ray photons interacting with matter, then we need a local characterization of the real samples and of the SRMs we will use and in a final step we have to compare the our findings. After this process we will have an insight into that what statistics predict as a limit due to uncertainty.

To the first topic there are several excellent books, tutorials and also free articles in the net. Several interactions as they are absorption, fluorescence, diffraction, etc. etc. affect the results of the analyses. The penetration depth of the primary radiation and the exit depth of the fluorescence radiation containing the information we are looking for. We call this in s general form matrix-effects.

The second. Here the composition of the material in use is important. That means we have to know not only about content in average we need information about the local distribution of the elements, e.g. are there small crystalline structures, or big ones or a dendritic form. Porosity, was the material subjected to big pressure like in the coining process or was it waltzed? Segregation of some elements at the grain boundaries are also of interest. All this aspects are affecting the results of a characterization via EDXRF. We had some years ago a discussion in France: someone proposes the 10€ cent coin as a standard. The coin is available in all European countries, so you have to take only one and the reference standard is ready. It was an illusion, in average the coins may have the same concentration but not in local regime. That means with a coin of Spain and one of Germany we obtained different results. The standards were different!! If we continue in the field of coins not only the composition is affecting the result. Also the morphology of the surface is influencing the data. Coins are at the surface not flat discs, they have a clear 3D structure. The result is again a higher deviation. You can also observe these kind of effect when finishing the surface of metal rods with abrasive paper of different granulation.

To the last topic: EDXRF analysis is a type of extended surface analysis. The information we obtain have an origin at not more 100 µm depth. If we look at a coin (e.g. 10 € cent) we are able to characterize the elemental composition at a layer around 10 % of the coin thickness (taking front and back). That is not more than 2.7% of the volume. Are these portions representative for the characterization? If we assume that the material is homogeneous yes. In the case of coins not. There are plated coins, chemically enriched elements at the surfaces of coins (Romans) and there are effects of depletion or enrichment due to the regular use of money.

My question is now: How good can be the validation of the results of unknown material? It is not only depending on the quality of the validation (numbers produced by the instrumental analytical devices, use of SRMs) it is much more. It requires your experience and a deep knowledge about the stuff you are dealing with. If we add all influences of the procedure we will get a (much) lager numeber as expexted. The contribution of the uncertainty of the analytical procedure is mostly accessible. With the resting part it is possible to produce house numbers...

Alex

 Mr. Katsifas,  Have you put yourself in contact with the Portable Artifacts scheme at the BM?   If not, give it a try.  They might be helpful.  

Usually XRF analysis means bulk analysis, meaning the sample is considered homogeneous in depth. Elemental depth gradients cannot be resolved with standard XRF geometry, thus, when measuring a sample with surface enrichment or depletion, quantification values are not strictly correct, as you are using a 'incorrect' modell of your sample. Just to give you an idea, in metals the information depth of fluorescence lines is on the order of a few 10s of µm. I guess a cross section would give you the easiest access to the stratigraphy. If non-destructiveness is mandatory, maybe techniques such as grazing incidence XRF might be usefull.

I am also confident, that there have been a couple of studies dealing with ancient coins, if not even book chapters.

Dear José,

please find these papers attached:

Andreas Haasis-Berner, Hörner aus Keramik – Wallfahrtsdevotionalien oder Signalhörner? Zeitschrift für Archäologie des Mittelalters 22, 1994, S. 15–38.

Günter Mangelsdorf, Das Aachhorn von Greifswald – ein Beitrag zur mittelalterlichen Devotionalienkunde, Bodendenkmalpflege in Mecklenburg-Vorpommern, Jahrbuch 39, 1991, S. 219–225.

The ceramic horn from Greifswald is from a context from the 15th century.

Best wishes,

Stefan

Dear Ms Mendez,

Check this website out... 

You will find links to each of the following methods of dating...and under those links the limits and some of the ranges of those methods are described. It should help answer your question.

Archaeometry - Archaeomagnetic And Paleomagnetic Dating

Archaeometry - Dendrochronology  

The longest individual tree ring chronologies developed to date have been for an 8,700-year California bristlecone pine sequence, and a 10,000-year sequence in Europe.

Archaeometry - Fission-track Dating

Archaeometry - Lithics

Archaeometry - Luminescence Dating

Archaeometry - Metals Analysis

Archaeometry - Obsidian Hydration Dating

Archaeometry - Paleobotany And Paleoethnobotany

Archaeometry - Potassium-argon Dating    For example this method can date rocks that were formed between 50,000 and two billion years ago.

Archaeometry - Radiocarbon Dating can date materials, formed between 300 and 40-50,000 years ago, that contain organic carbon.

Have you considered organic matter? Sometimes organic matter is left in the voids. They can look fibrous. People often used hair, vegetal matter (chaff, grass, etc.) and dung-which can contain both hair and vegetal matter- as temper in pots. Organic fibers may also be naturally present in the raw materials. The remnants may remain,especially in low fired pots.  If you had a picture, it would be easier to help.

If you are interested in firing conditions you should have a read of Maniatis and Tite 1981. Technological examination of Neolithic-Bronze Age pottery from central and southeast Europe and from the Near East. J. of Archaeological Science 8, 59-76. If you are interested in painting technology, I would suggest looking up the work doen by Eleni Aloupi and Maniatis, also by Vassilis Kilikoglou. If you are interested in mechanical properties of ancient pottery look up the work of Anno Hein and also that of Noémi Müller who works mainly on mechanics of cooking pottery through mineralogy, chemical composition and microstructure.

 Thanks everyone, I appreciate all your comments and suggestions. As most of archaeologists I assumed this "something" to be the trace of organic material (wood/charcoal), which would be the most logical explanation regarding finding context - iron smelting site. And many of them really are, but wood or charcoal have different pattern. After visual and microscopy inspection the version of organic material was rejected by researchers on wooden material and dendrochronology. The organic material is too soft to leave defined traces like these. Wooden material would leave less regular undefined pattern, which is more similar to fiber or tuft. The item under consideration displays very regular linear texture with strictly paralell lines streaching on both sides of "stem". I added more images of items with similar pattern and also added one which is identified as potential trace of organic (wooden?) material. They look different. Meantime, my latest explanation of this "something" is non-organic material used as flux, potentially some kind of invertebrates? Unfortunately, I haven't seen anything like this.  

Thank  you . J F

I hope, Anne Hasler, that your question has been adequately addressed/answered!

As there is an 'internet record', I feel obliged to respond to your last comment, Magdalena Stoyanova, for those that may read this thread in the future. There are a number of reasons why publications might not be cited, including awareness, accessibility as well as linguistic barriers. Most able academics do their best to overcome such issues/obstacles, though it is not always possible to truly conduct a 'complete' literature survey.

The quality of research publications, in general, can be measured in many ways - the authors and articles I have suggested are multi-lingual with English as their second language, and as such, I highly doubt that their omission of Russian papers is deliberate or calculated

It would be more appropriate for your critique, or evaluation, to be presented in a proper forum, such as a published commentary, which can thereafter be reviewed and verified. The best approach would be circulate an email to glass specialists and related academics, raising awareness of the data you mention, so that they can engage with it; I suspect that due to the aforementioned reasons (accessibility, awareness, language), that such papers could have been missed, without any untoward intent, as you suggest.

If you are questioning the integrity and quality of these scientific papers, based on their lack of Russian articles, in a non-reviewed online discussion board such as this, then it would be appropriate to inform those scholars (of whom you are discussing) of the existence of this forum, so that they might have the opportunity to respond. I am sure they will be pleased to learn more about the Russian data you have highlighted.

No problem.

Best,

Julie

Thanks a lot to all of you for your answers. I really looks like the conidia of Leandria momordicae. The fact is that the presence in this kiln walls should be explained as a fungi presence after the kiln stopped its activity. This is the kiln chamber just excavated in the soil.

 Dear N. Nezafati,

I think you should look at some articles which related to gold production in Anatolia and Aegean during Bronze Ages for some progress your study.

1. W. J. Young, 1972, ' The Fabulous Gold of the Pactolus Valley', Bulletin: Museum of Fine Arts, Boston, vol. LXX, 1972, no. 359, 5-13.

2. JESUS, de P. S., 1980, The Development of Prehistoric Mining and Metallurgy in Anatolia, BAR International Series 74 ( i ),Oxford. see pages 71 and 85, 86, 88.  

 3. George M. A. Hanfmann, 'Archeological Explorations of Sardis', Bulletin of the American Academy of Arts and Sciences, Vol. 27, No. 2 (Nov., 1973),pp. 13-26. see page 20. 

4. K. Branigan, 1974, Aegean Metalwork in the Early and Middle Bronze Ages, Oxford. See p. 90.

best wishes,

Here in Italy, we prefere the term of "Sciences applied to Cultural Heritage", University courses on these topics (including physical methodologies, such as C14 dating, XRF, Raman Scattering, IR fluorescence and many other, as well as statistics, paleo-botanics, anthropolgy, etc) are held in many Italian Universities both at degree and PhD level. Of course a Doctor in Sciences applied to Cultural Heritage is not an archaeologist, however he is a professional whose presence in any archeological mission is precious. For myself, I am an astronomer and I joined a number of archaeological mission when professional archeologists asked me if it was possible to confirm or deny on a physical base if the hypothesis of an astronomical meaning in some artifacts was acceptable. But I just measure angles and make astronomical computation, giving a statistical evaluation of the hypothesis they suggested. I will never try to make an hypothesis on an archeaological artifact by myself, since I have not a professional knowledge on the cuture that produced the artifact.

Dear Gaia

It is my pleasure to help, according to my experience the book of crystal growth by Pamplin may help. For just information I was his last PhD student to work on crystal growth in the University of Bath. Each type of materials or compounds needs special technique and experience for growing and preparation in their crystalline form. Oxides are more difficult for preparation in the form of large bulk single crystals, while thin film form preparation is much easier. You can evaporate Sn as a pure element then annealed at open air or Oxygen atmosphere at a temperature lower than its melting point for a certain time depending on film thickness and the temperature of annealing.

For more details and questions you can contact directly.

Prof. Dr. M S Omar

Dear Gabriel,

The main issue is your question about the samples: provenance, technology or deterioration?

If you like to study historic potteries, you should use some analytical methods such as petrography (microscopy) and elemental and phase analyses suchas XRD, XRF and etc. The method should establish based on your question. More detailed information may help to answer better.

Regards

For my PhD I carried out analysis of soil samples taken from topsoil, subsoil and inside targeted archaeological features. The K enhancements, in some of my case studies (in Scotland), were generally associated with archaeological deposits with higher concentration of organic matter, ash and charcoal. I found increased K-Fe-Ti in archaeological deposits associated with higher organic, clay mineral content + metal oxides in an archaeological deposit concealed in Aeolian sands (non- cultivated field). These are some very general points from my sites. Here some good references that I hope may help you.

Best,

Carmen

Oonk, S., Slomp, C.P., Huisman, D.J., 2009a. Geochemistry as an aid in archaeological prospection and site interpretation: Current issues and research directions. Archaeological Prospection 16, 35–51.

Oonk, S., Slomp, C.P., Huisman, D.J., Vriend, S.P., 2009b. Effects of site lithology on geochemical signatures of human occupation in archaeological house plans in the Netherlands. Journal of Archaeological Science 36, 1215–1228.

Oonk, S., Slomp, C.P., Huisman, D.J., Vriend, S.P., 2009c. Geochemical and mineralogical investigation of domestic archaeological soil features at the Tiel-Passewaaij site, The Netherlands. Journal of Geochemical Exploration 101, 155–165.

Wilson, C.A., Davidson, D.A., Cresser, M.S., 2005. An evaluation of multielement analysis of historic soil contamination to differentiate space use and former function in and around abandoned farms. The Holocene 15, 1094–1099.

Wilson, C.A., Cresser, M.S., Davidson, D.A., 2006. Sequential element extraction of soils from abandoned farms: an investigation of the partitioning of anthropogenic element inputs from historic land use. Journal of Environmental Monitoring 8, 439–44.

Wilson, C.A., Davidson, D.A., Cresser, M.S., 2007. Evaluating the use of multi-element soil analysis in archaeology: a study of a post-medieval croft (Olligarth) in Shetland. Atti della Società Toscana di Scienze Naturali 112, 69–78.

Wilson, C.A., Davidson, D.A., Cresser, M.S., 2008. Multi-element soil analysis: an assessment of its potential as an aid to archaeological interpretation. Journal of Archaeological Science 35, 412–424.

Wilson, C.A., Davidson, D.A., Cresser, M.S., 2009. An evaluation of the site specificity of soil elemental signatures for identifying and interpreting former functional areas. Journal of Archaeological Science 36, 2327–2334.

Dear Anna, dear Walter,

there is a new article about marbles from Estremoz and other quarries from Lusitania; including stable (O, C) and Sr isotopic results and petrograhic description. Maybe it can help you at first:

Taelman et al (2013): Roman marble from Lusitania: petrographic and geochemical characterisation. Journal of Archaeological Science 40, 2227-2236.

Yours,

Judit