‘Endshock’ and flake analysis

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We are back from our weeks holiday in Mid-Wales and knapping wise I didn’t have much more Johnstone Solutrean success. Ultimately from the two large sheets of Johnstone I took with me I produced the previously discussed Solutrean point, and lots of smaller blanks that will be suitable for arrowheads. The arrowhead blanks are a bi-product and so not relevant to this discussion, however I think it is interesting to explore where my problems lie. One problem that happened more than once was ‘endshock’ (see above image). When this piece snapped in the middle I was actually working on thinning one of the ends. This is how I ended up with the arrowhead blanks.

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A second issue that deserves attention was how I was effectively thinning the pieces. Above are five useful penetrative thinning flakes that successfully removed the original surface, however, I couldn’t produce these consistently.  The above photograph shows the ventral, or inner surface of flakes I preserved for reference, to see what was going on when it worked.

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The above image is of the first three flakes but the dorsal, or outer face, showing the amount of flat original surface successfully removed. They are organised in size order with the first being the largest and therefore most successful. This first flake is 49 mm in length and the platform, or the part of the flake that received the impact is 9 mm in length and 4 mm in width. So all the energy from the blow was transferred into the body of the blank being worked through that small area. The platform can be considered ‘plain’ in that it has not been worked in any way. Another useful analytical aspect is the ‘Platform Angle’. If the angle between the face of the platform and the dorsal surface on any flake is measured it will usually be 90 degrees or less. At any greater angle the energy of the blow would not be concentrated and therefore ineffective. The platform angle on this piece is about 70 degrees. This tells us that the energy imparted from the heavy soft hammer blow entered the piece at 70 degrees to the dorsal surface through a plain small platform. Onto the second longest flake.

 

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The second longest flake is 42 mm in length and the platform seems to be a small plain section some 4 mm by 2 mm. Emerging from the platform on the ventral surface we can see what is called an ‘Eraillure Scar’. This scar illustrates that a mini flake was removed from the main flake at the same time as the main flake was removed from the blank. For my purposes it acts as a signpost to the point of impact. Platform angle is more like 90 degrees on this one. On to the third flake.

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This one is 35 mm in length and the large erailiure scar indicates a single raised point of impact. This kind of platform is termed ‘Punctiform’, or point like, probably 2mm x 2mm, and the platform angle is again close to 90 degrees.

So how can this help us, or help me? The endshock I think is in many ways simply a symptom of a lack of attention. Firstly, the sound of a hit tells me if the platform has been correctly produced because I can hear the sound of the flake being taken off. Alternatively, if I can hear the dull thud of unstoppable antler against immovable blank then there is a potential problem. This can be exacerbated if the blank is not supported by the knapper’s body. I was guilty of both these ‘crimes’ when the above example occurred. So prepare a good platform; support the blank (perhaps by resting it on my thigh); listen for problems when I hit it. Regarding the flake analysis, it seems to confirm that a platform angle of between 70 and 90 degrees, and a sticky out point in these instances have led to long removals taking off decent flakes.

It has been busy since we came home and it has taken me a while to finish this blog post. I think I understood most of this stuff already before analysing these flakes, and so what this highlights is my movement between systematic preparation and a more intuitive percussion. Sometimes I pay attention, and sometimes I don’t, and the result is inconsistent flaking. If I can stay focused on the above points then in theory I should be able to move on a stage. I think if I can pay attention and get a better result, then my intuitive percussion will also improve.

This can be described usefully by a four stage learning model. The four stages of learning a new skill are:

  1. Unconsciously incompetent (it looks easy because you don’t know you can’t do it).
  2. Consciously incompetent (you try it and realise you can’t do it).
  3. Consciously competent (you progress by maintaining intense concentration).
  4. Unconsciously competent (you have got it and are in the zone!)

When it comes to Johnstone Solutrean points I am currently just past ‘Consciously incompetent’ and approaching ‘Consciously competent’. I was however in the zone on Saturday, but that is a different blog post!

 

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Solutrean, Johnstone, Holiday

We are on holiday in mid-Wales and I have brought my knapping gear, some bathroom ceramic, and am busy testing out the ‘thinning then shaping’ approach discussed in the previous post. This was yesterdays effort and I like it.

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Complete bifacial thinning with no original surface left. I didn’t bring my calipers but my best estimate using a ruler is that it is maximum width 35mm and maximum thickness 10mm which makes the ratio 3.5, and therefore Early.

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The profile view below shows how it has been thinned more effectively in the lower section than in upper. If I were to use the lower minimum thickness then it would be 35mm divided by 8mm making a ratio of around 4.4, and therefore approaching a Middle.

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The lesson here then is consistency, and whilst there is some way to go, I have my next attempt waiting for me outside, so I better stop typing!

The game is afoot!

I have just re-read a paper co-authored by Bruce Bradley regarding a Solutrean site in France. From the lithic debris recovered the authors were able to reconstruct the production process for large thin Solutrean ‘laurel leaf’ points. The key thing that is useful for me is that the authors posit a formula for recognising the stage of production. They divided the width of the piece by its thickness to produce a figure, and this figure indicated how ‘finished’ the piece was. Their model had four phases: Early – 3.6, Middle – 4.8, Late – 5.7, and Finished – 5.2. What these ratios tell us is that thinning was a primary activity that reached its apogee in the Late phase. Shaping would then reduce the width and therefore the Finished ratio would go down slightly. With this in mind I had another go with the aim of removing all of each surface to reduce thickness. As you can see, still a little original surface left on this face towards the front.

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And a tiny, tiny piece of the glossed material left on this second face. I thought that would be enough to at least reduce the thickness. As I was by now losing width I didn’t take it further.

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And the bad news? the ratio for this piece is 3.5, so technically still an Early in need of significant thinning. I measured all my previous pieces and the best one was unsurprisingly the widest at a ratio of 4, so again still an Early. 

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I now have a thickness model to work to that tells me how well, or not, my thinning is progressing, and I find that quite exciting. It is ultimately going to be a game of maintaining width whilst being able to take off long flakes. Interesting stuff.

Thierry Aubry, Bruce Bradley, Miguel Almeida, Bertrand Walter, Maria João Neves, Jacques Pelegrin, Michel Lenoir & Marc Tiffagom (2008) Solutrean laurel leaf production at Maîtreaux: an experimental approach guided by techno-economic analysis, World Archaeology, 40:1, 48-66, DOI: 10.1080/00438240701843538

Exploring the concept and practice of ‘overshot’ flaking

This point was reduced in the same way as the previous example, using a heavy-ish soft hammer. Once it was approximately the right shape I started using my pressure flaker to isolate protruding points. Isolating the protuberances weakens them, whilst at the same time improving the chances that all the energy from the blow will be absorbed by that small area. The result is an increased chance that the blow will take off a longer flake. On the photo below I wanted to attack the ceramic gloss surface to the left of upper centre.

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After isolating the platform I took off a good flake that travelled half way across the face and removed a significant portion of the gloss surface. The method works, as I knew it would but the angle of the surface is also a factor that needs consideration.

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The process here is the same as the one John Lord introduced me to when making a handaxe. Essentially you use the abrading stone or pressure flaker to sculpt the ideal platform so that all the energy from the hit is concentrated in one place. What this means in effect is that each platform has to be systematically sculpted before each blow. For me this means two things: firstly I need to be more systematic and less intuitive in my reduction process; secondly I need a really good and finely shaped abrading stone to really pick out the platforms.

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This is the finished artefact and the better of the two faces. As you can see, one of the removals has travelled two thirds of the way across. That in many ways is an ideal removal as it has changed the angle of the face. I think that is the process in essence, deep removals that reduce the thickness of the piece, and by default the angle of the face. The overshot flaking I think is an earlier stage phenomenon that, when using flint tablets, allows you to get to the thinned stage that I am starting at. I wonder if the results of overshot flaking leave a face that is easier to flake than this artificially tabular bathroom material. I need to do a few more, and generate some more data. I can then move onto flint and compare and contrast. So expect a few more of these.

More on Solutrean points and ‘Johnstone’ or bathroom ceramic

I am still playing with my first batch of this lot of ‘Johnstone’, or bathroom ceramic, and am onto my second Solutrean point. As discussed earlier, I am familiarising myself with the background to these artefacts whilst exploring this particular material affordances of bathroom ceramic. There are lots of facets that are potentially of relevance, but essentially the archaeological points are bifacially worked, with some being very long and very thin. They were produced around the time of the Last Glacial Maximum, in refugia in France, Spain and Portugal. The most impressive (and probably unusable) pieces are from a cache at a site called Volgu in France. Below is an image of actual Solutrean material from the Musee d’Archeologie Nationale in France.

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By World Imaging [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, from Wikimedia Commons.

These points were thinned using a soft hammer and sometimes the tips were pressure flaked. Bruce Bradley, an experimental flint knapper at the University of Exeter, has emphasised the use of an ‘overshot’ technique in thinning. This involves establishing a spur (or sticky out bit) on the edge, and then hitting that to take off a long flake that travels completely across the face. Whilst very difficult to achieve it provides an efficient method for thinning a piece. When Kim Akerman made his Roseleaf Kimberley point he did exactly this by mistake.

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The bathroom ceramic is already pre-thinned and so effectively I am starting at a late soft hammer phase of reduction. This is my most recent example, using a soft antler hammer and pressure flaking. I have not attempted the overshot technique as yet but I grasp, conceptually, how it may work.

Solutrean 1

This is the second face, with a little step fracture island towards the centre of the piece. This would be an ideal candidate for an overshot flake to remove the remaining glazed surface.

Solutrean 2

So the next Solutrean / Johnstone instalment will be overshot flakes. Let’s see how that goes.

Solutrean points from bathroom ceramic

It has been a while and that lack of knapping has taken me back a few stages, or so it feels. For unknown reasons, probably related to tidying up the back yard, I have started playing with the plenty of bathroom ceramic I have now neatly stacked on top of my wood store. I have said elsewhere how my soft hammer work is possibly my weakest area at the moment.

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Working with this material is therefore interesting. Using a hard hammer I have had lots of problems, but primarily endshock. I noticed on a Youtube video someone using antler to thin some of this material successfully, and so I have been playing with the same.

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I used a heavy and light antler hammer to bifacially work this piece. I was surprised at how well the material responded and worked with the heavy antler. Ultimately that was almost all I used. I have developed a new variation of the Metin Erin resting arm on knee method. I hold the piece of material being knapped out now, rather than resting it on my leg. This works better.

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You can see on the floor the two antler hammers used. I did a little hard hammer at the beginning before abandoning it. This is my second attempt and the heavy antler hammer has opened up new possibilities. I was sticking with the light hammer, partly because I like it, and partly because I was worried about endshock with a heavier hammer. However, the antler seems to work well with the ceramic and the heavy hammer is obviously the right tool. I should say that the ceramic is quite thick, over 12mm.

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I think I know about Solutrean points, but I am going to familiarise myself with them before I write the next post on these artefacts. Above are the reference books I keep on my shelf. There is also an excellent paper by Anthony Sinclair at Liverpool called Constellations of Knowledge (downloadable here) about the social implications of these points. I now have a new theme!