Category Archives: Photography

The unexpected little joys of lithic use wear analyses II

A little while ago I posted a photo of a crystal inclusion in a white flint bladelet. I promised to post some more, whenever I think of it. So here is another example of the beautiful things I have encountered doing the use wear analyses. This burnt flint bladelet, like the last example from Late Mesolithic layers at Lutter/St. Joseph, France, did not show any signs of use. However, the microscope does show beautifully the microfossils within the flint, or possibly radiolarite, out of which it was made. And, like the last example, this photo also shows the possibilities of the digital microscope I have been able to use for the study of the use wear analyses of Late Mesolithic artefacts from two Lutter/St. Joseph, France and Arconciel/La Souche, Switzerland.

Microfossils, Lutter/St. Joseph. France. Mesolithic

Micro-fossils in a Late Mesolithic burnt retouched bladelet from Lutter/St. Joseph, France. Composite (focus stacking) image (150x) I made with a Keyence Digital microscope (Dep. Of Geosciences at the Université du Fribourg, Switzerland.)

The unexpected little joys of lithic use wear analyses I

Sometimes, when doing the microscopic analyses of use wear traces I come across fascinating things that have little to do with the actual use wear of the tools being studied. Instead they either provide something of a background to their natural origins or are just visually interesting. The digital microscope I have been using at the Dep. Of Geosciences at the Université de Fribourg, Switzerland has many technical possibilities. It allows me to document not only the use wear traces using a variety of photographic technologies. It also provides the opportunity to record composite photos such as this one of an otherwise not very interesting bladelet fragment from the site of Lutter/St. Joseph, in the French Alsace. I’ll try to publish a few more of such examples in the near future.

Lutter/St. Joseph, France. Crystal inclusion in a Mesolithic flint bladelet.

Crystal inclusion in a Late Mesolithic flint bladelet fragment from Lutter/St. Joseph, France. Composite (focus stacking) image (100x) I made with a Keyence Digital microscope (Dep. Of Geosciences at the Université du Fribourg, Switzerland.)

Image

Autumn writing

We have spend a few amazing autumn days on a lake in the Swiss Alps. My amazing, supportive wife has now left me alone at the lake to spend a week to try and finish a section of my PhD thesis in splendid solitude.

Well that, and to eat the last ripe figs of the tree!

An era coming to an end? Alpine archaeology will never be the same again!

So, that’s that. Last week I had the honour and immense pleasure to help dig a few trenches at Las Gondas in the Fimbertal, between the Lower Engadin and Paznaun valleys. The Rückwege project was initiated by Thomas Reitmaier in 2006 and this might or might not turn out to have been the last ever field season. 10 years of multi-disciplinary and highly successful alpine archaeological fieldwork have come to an end. It was a fantastic time and a great week away from the PhD. A week in which a wonderful group of archaeologists and friends, who have all been involved in the project over the years, got together to excavate a system of animal pens in the beautiful Fimber valley. We managed to sort out the stratigraphy and expect it to be prehistoric, perhaps chronologically comparable to the Iron Age hut ruins we excavated further down the valley. But, as so often in the Alps, finds are scarce. So, we’ll have to wait for the 14-C dates to come back.

I would like to thank my friends, and especially Thomas, for their companionship, the laughs, the snoring, the Streusel, the EIER, the Schnapps, wine and beer, the snow, Lassiter, the tons of charcoal and the many buckets full of dirt and stone. Do have a look at Thomas’s post on  the Silvretta-Historica blog, which I’ve linked to below as well!

 sodalla – wir sind also schon wieder gut zurück aus dem schönen fimbertal und einer sehr erfolgreichen einwöchigen grabungskampagne im gebiet las gondas  … . das hauptanliegen, die dortigen pferchstrukturen genauer zu untersuchen und hoffentlich im verlauf der nächsten wochen auch mittels 14c-datierungen zeitlich einzuordnen, haben wir mit einem ausgezeichneten und hochmotivierten grabungsteam problemlos erreicht, trotz der mitunter etwas widrigen wetterbedingungen …    (CLICK ON THIS LINK TO THE SILVRETTA-HISTORICA PROJECT BLOG FOR MORE INFO AND LOTS OF GREAT PHOTOS FROM THE FIELDWORK!)

Visualising lithic use wear traces – photo stacking

It is not always immediately apparent to non-specialists what we – use wear analysts – do and see and how we can be certain of our observations. This is partially due to the imagery many use wear analysts produce. In a recent paper A. van Gijn (2013) reflects on the current state of the field of lithic microwear or use-wear analysis and points out a number of aspects of our work in which improvements are possible or even necessary. These, in my opinion rightly, include an increase in sample sizes (e.g. by scanning tools with a stereomicroscope before moving on to higher magnifications); more incorporation of ethnographic data; a standardisation of practise and nomenclature; embedding the use wear traces in the cultural biographies of artefacts and providing better quality imagery.

The basal end of a Mesolithic scraper from Arconciel/La Souche, Switzerland (quartzit au grain fin/Ölquarzit). Left a normal photo. Right a composite photo of the same part of the artefact. Taken with a Keyence Digital Microscope.

The basal end of a Mesolithic scraper from Arconciel/La Souche, Switzerland (quartzit au grain fin/Ölquarzit). Left a normal photo. Right a composite photo of the same part of the artefact. Taken with a Keyence Digital Microscope.

The last point can be achieved by photo-stacking through the use of specialist software or microscopes, such as the digital microscope I use, which are able to make composite photos. The image above shows what photo stacking or composite photos allows you to do.

One major drawback of the microwear approach is the lack of convincing visual evidence. The pictures generally shown at meetings are fuzzy and lack depth of field. Usually only a small part of the photograph is sharp, namely the spot of polish we want to address. Although insiders may usually see and recognize what is being discussed, it is little wonder that the general audience has no idea what it has to look at and remains rather skeptical. There is much to gain from improving the visualization of the microwear traces. – A. L. van Gijn (2013 – p. 3)

Typically, it is difficult to make microscopic photos of larger parts of artefacts that are in focus. Photo stacking, however, allows exactly this: an increased depth of field with much larger parts of the artefact shown in focus. This way not only the traces, but also their contexts can be visualised. I find this technique does not work very well in all situations or for all raw-materials or for all traces. Nonetheless, it makes our work more effective and it will surely allow us to communicate our methodology and findings much better not only to fellow specialists, but also to non-use wear specialist archaeologists and the general public.

ResearchBlogging.org

Gijn, van A. (2013). Science and interpretation in microwear studies, Journal of Archaeological Science, DOI:

Traversar III – a photographic record

Autumn has arrived in the Alps. The grass is losing its green lustre, leaves are slowly turning brown, farmers have moved their life-stock from alpine summer pastures down into the valleys and snow is expected later this week. Time to have a first cautious look back on this summer’s archaeological activities in the Swiss Alps.

I already wrote once about a small project we, a select team of expert alpine archaeologists (of course), started with the aim to study the archaeological remains at a number of the most important passes in the Grisons. This summer we were mostly active in the San Bernardinopass region. We also surveyed some areas in the Upper Engadin Valley which are to be subject to development in the near future. (For this we were officially commissioned by the Archaeological Unit of the Canton of Graubünden.)

We were lucky with the weather and were able to do all we set out to. We had some interesting results and although dating is difficult at this stage, we expect our finds to be both of medieval/early modern as well as prehistoric dates. While we are cleaning up the documentation, analysing the results and waiting for the C14 dates, I thought I posts some photos giving an impression of the fieldwork.

And if you are interested in the archaeology of the Alps, why not have a look at the alpine archaeology blog? Students of the Alpine Archaeology: tools and techniques e-learning course at the Universität Zürich will be blogging here this semester (DE).

During the fieldwork we discussed archaeology and bandes dessinée. We talked about the book Le soleil des morts, by comic artist A. Houot and archaeologists A. Gallay. (I believe it is not in print anymore.) I would be very interested in hearing about other good examples (in any language), so do get in touch!

The history of lithic use wear analysis II – Qu’était l’objet?

The fragmentary nature of many archaeological finds can make our work challenging. The anaerobic conditions of the Neolithic and Bronze Age lake side sites of peri-alpine Europe, however, can provide some very welcome insights into the organic part of prehistoric tool kits. It is no surprise that the almost completely preserved sickle from Solferino inspired French archaeologist André Vayson de Pradenne (1919) to address the still unresolved issues of the use of certain lithic artefacts and the polish that can be seen on them.

This sickle was found some time before Vayson saw it in peat bogs just south of the Lake of Garda. It consisted of a number flint blades that fitted seamlessly next to each other in a groove in a wooden haft. They were glued in with a smooth mastic and protruded ca. 12mm from the haft. The form would suggest use as a knife or saw would be impossible. Vayson commenced on a large comparative study of all known sickle and sickle like artefacts from Europe and the Near East. And although he does not describe them elaborately, he does some experiments, trying to work wood and grasses with sickle like flint tools. He come to the conclusion that the artefacts must have been used as sickles, but also argued that wood as well as grasses can produce polish.

Modern serrated flake with broad band of lustre experimentally produced by cutting straw (x2). From Curwen 1930.

Modern serrated flake with broad band of lustre experimentally produced by cutting straw (x2). From Curwen 1930.

British surgeon and archaeologist E. C. Curwen shows much respect for Vayson’s work, whose 1919 paper he summarises elaborately in English in his article in Antiquity (Curwen, 1930). He is, however, not satisfied with Vayson’s results and does more experiments from which he concludes that working grasses and woods each produces distinctive kinds of polish.

When Dorothy Garrod finds sickle blades set in bone handles with polish from Natufian layers in Palestine, this raises new questions about the timing and process of the start of cereal domestication in the Near East. René Neuville discusses the issue in a 1934 paper, building on Vayson’s work and criticizing part of Curwen’s 1930 conclusions (Neuville, 1934). As a result Curwen decides to do more experiments in order to finally get to the bottom of what causes polishes and to address the domestication questions (Curwen, 1935).

Aiming to reproduce more realistic durations of tool use, Curwen devises a mechanical experiment. He sets a number of experimental artefacts made from two kinds of flint into an electric lathe and as such they were used to `work´ bone, oak wood and compressed straw with (30 minutes each; straw 3500 rotations/minute, bone and wood 2500). The results supported the view that lustre and its development is not just the result of the intensity of use, but also conditioned by the worked material. In the case of these sickles Curwen concluded that the worked material was probably a siliceous plant material of “a yielding nature”. It was thus established that the type of tool, the worked material, the length of use as well as the kind of use all influence the build-up of polish. With this Spurrell, Vayson, Neuville and Curwen had set the parameters for most use wear studies to this date.

It is fascinating to see the photographs Curwen used in both, otherwise relatively sparsely illustrated, 1930 and 1935 publications to illustrate his findings. Although his photos are not microscopic (scale 2:1 and 2½:1), their aesthetics foreshadow those of the microscopic photography of use wear traces on lithic artefacts that have become the norm during the past sixty years or so. The photography used by most presenters at the Usewear2012 conference last September still stuck to these aesthetics, which can be described as a visual vocabulary. Only recently, really with the appearance of digital photography and SEM-technology, do we see a widening of this visual vocabulary within the discipline of use wear analysis.

Lastly, Curwen’s use of mechanic experiments seem to have been rather forwards looking. It has not become the norm in experimental archaeology, neither in use wear analyses, but it might have a future after all. The mechanical experiments allowed Curwen to reproduce intense artefact use with each of the experimental artefacts and enabled him control the parameters of his study and to make direct comparisons between the polish developed on each tool. In a study by Iovita et al (Iovita et al. In Press) mechanised experiments are used to control the experiments parameters and enable reproducibility. Mechanised experiments might also allow for larger reference samples for use wear studies.

Microscopy has not entered the discipline of lithic use wear studies in the 1930’s yet. Researchers had been able to define the factors causing polish and the discipline’s visual repertoire had been established by a small group of researchers working across Europa and the Near East engaged in an international debate, doing experiments and willing to try new methods and to learn from each other.

Literature

CURWEN, E. C. 1930. Prehistoric Flint Sickles Antiquity, 4, 179-188.

CURWEN, E. C. 1935. Agriculture and the Flint Sickle in Palestine. Antiquity, 9, 62-66.

IOVITA, R., SCHÖNEKEß, H., GAUDZINSKI-WINDHEUSER, S. & JÄGER, F. In Press, Projectile impact fractures and launching mechanisms: results of a controlled ballistic experiment using replica Levallois points. Journal of Archaeological Science.

NEUVILLE, R. 1934. Les débuts de l’agriculture et la faucille préhistorique en Palestine, Jerusalem.

VAYSON DE PRADENNE, A. 1919. Faucille préhistorique de Solférino. L’Anthropologie, XXIX, 393-422.