|ARTICLES ABOUT EXPERIMENTAL MAKING OF 'PEBBLE TOOLS'|
Content of this post:
1. Experiments on raw material samples from the Belgian Kempen area, similar to the raw materials used in the artifact -assemblages ( dec 2011) to be updated
2. Some experiments on quartz from the river
3. Experimental making of small pebble tools from the river Moselle (March 2010. France) experiments by Hervé Beaudouin, archaeologist from Lorraine ( weblog: Préhistoire en Lorraine)
4. Some experiments on a very limited pebble clast from the surface at Niels -bij -As : the production of very small tools
1. Experiments on raw material samples from the Belgian Kempen area, similar to the raw materials used in the artifact -assemblages
|Small hints on artifacts provide information about the use of the tool, like the small fracture, visible ( blue point) at the tip of the point of this assumed ''pic '. But is thus really the truth? How can we distinguish natural fractures from use wear of intentional retouch? Experiments are helpful, especially in understanding techniques applied on local raw materials.|
For the experiments, the raw materials have been collected from the find sports, to have a better comparison between experimental made tools and prehistoric tools.
Tool properties at the main site cluster of the MA - project are the best studied part, so this is the main starting point for the man-made prehistoric artifacts control group :
( characteristics of the artifact group, found at MA4:)
1. brown, mostly egg- shaped, fine grained pebbles were chosen, without inclusions
2. the angle of the flake removal is different , but the low angles prevail in the assemblage
3. the number of flake removals is between 1 and 7 /8 depending on the size of the pebble and the desired function.
4. though no anvil is found ( yet), it is most likely tools were made on a flat anvil, using hard hammer technique ( looking at the scars on almost every pebble tool)
5. the choice of raw material is the determinant factor in the final tool design: round pebbles show different flaking patterns ( rounded, shell shaped) compared to quartzite blocks with quartz veins, red sandstones, conglomerates, etc.
6. micro -choppers and chopping tools are present in the assemblages. This requires a more sophisticated precise technique
7. Angles of processed edges usually below 75 degrees
|Refit of naturally broken pebble|
|Naturally broken pebbles show steep angles and a lack of bulb complexes and real impact points.|
Some simple experiments showed some important facts about the technique of pebble tool production:
1) free hand flaking almost impossible. it's like you take a piece of metal and slam it with a hammer, painful for the hand; hammer- anvil technique is very fruitful
2) hammer size 2- 3 times bigger than stone that is to be flaked
3) shape of hammer stone less important than weight, but round pebbles preferred
4. choppers are easily made when placed in the right angle on the anvil (low angle)
5. decortication strikes on the quartzite pebble surface only are produced under high angles ( "steep retouch") and also could be interpret as 'mistakes', like steps and hinges.
6. Tool production in this manner gives no wave patterns, impact points not always visible, no expressive bulb, or even "inversed bulbs"(with the strike the whole bulb section has splintered).
Quick tool making at the Helle brook at Eupen, Belgium on unselected pebbles from the brook bed; simple choppers were made in less than one minute, but a pre - shaped rounded edge was required to make them. During winter time, the pebbles are very cold, they are hardly to hold and therefore are very difficult to be processed.
|The Helle, (Hillbach)small brook near Eupen in Belgium, Hautes Fagnes/ Höhes Venn|
|Small gravel beach at the present brook Helle ( Eupen), showing different dimensions of gravels and different types of gravels together.Early man could just pick up pre- selected pebbles to make tools.|
|Before the striking (unsharp picture, but no other available)|
|After the striking, the cutting edge is rather sharp. The percussion impact lines are slightly visible in the quartzite surface of the flake removal, the bulb- complex is visible at the left.|
Start of this project: januar/ februar 2012
End of project : autumn 2012
Main questions in the experiments
Pebbles might get naturally broken, giving patterns that are similar or different from man-made, prehistoric pebble tools. Characteristics of man -made tools are frequently described ( Bordes 1961, Whiteacker 2003, Hardaker at earthmeasure ) so this is not the objective of the experiments.
Early hominids had the availability of exposed river gravels, making their tools from these gravels. In the Kempen- area two types of gravels were used: the late Elsterian fine- very fine gravels containing black flint and the much more crude gravels originating from early Elsterian/ late Cromerian period as in the original stratigraphy this gravel type lies directly below it. Both gravel types have their limits and possibilities, depending on purity, grain size, dimensions and typical predetermined fracture patterns.
Main purpose of the experiments is to find answers to the following questions:
1) Using the anvil technique, what angles have been used?
2) What differences are there using different types of hammer stones?
3) How did they make the quartzite micro- choppers/ micro- chopping tools?
4) How did they make the bifacial retouched small rounded flint pebbles
5) What are the production methods of flakes without prolonged bulbs?
6) How does the deliberate stepped fraction work?
7) How can we distinguish naturally patterns from man- made patterns, to be sure we deal with man-made artifacts on the local gravel types?
Local raw materials to use in the experiments ( gravel)
1. round to oval brown- brown grey colored pebbles, fine grained structure
2. grey quartzites containing veins of quartz
3. brownish sandstones
4. dark grey clastic shales
5. red sandstones
last update January 30, 2012
(To be continued ! )
2. Some experiments on quartz from the river
Tarn (2010 ) France
|The author busy with the experiment at the Tarn river (F)|
Pebble tools, made from stones from the river gravel bed could be made from quartz (1). Such tools are not always easy to recognise for the (amateur -) archaeologist. One way to find out the processing and the limits of quartz used for tool production, is to make them experimental. Reports have been made on experimental processed quartz tools with classification (2) but they are not always easy to read.
Choice of raw material
In certain regions of
Europe good quality flint to make tools is not
available, so other materials were used for tool production. In big parts
of Southern France and South- East Europe quartz and quartzite
was an alternative ressource (3).In the river Tarn in the French region of the
CÃ©vennes, quartz is availible ( 4) as I
could determine in very low percentage, I estimate less than 1 % ( main part is
composed of granite).
The main objective to make some tools from selected quartz from the present river terrace gravelbed was to see how it would be to make such tools, and to get examples of quartz with processed edges. Thus, I could compare prehistoric tools with experimental made tools. Another objective was, to see how easy it would be to make a disposable tool from a quartz, since this material was the only raw material found in the riverbed gravel to make a tool with a cutting edge. Cobbles of granite were amply present in the right ( rounded) sizes and shapes, to be used as a hammerstone.
The experiment ( 20 – 06- 2011, 21 -06 2011 and 24 -06 2011)
(a) Searching the proper materials and a working spot
At the channel edge of the river
Tarn, north from the community of Cocures I found two
different spots to search for quartz. It took some time to find the right
quartz to be processed. Lots of pieces of quartz were damaged somehow by frost
( frostridges) and these stones were not suitable, like with common flint. I
found several pieces of nice white – dull quartz, sometimes with brown-yellow
patinas om it. Rounded quartz was absent.
To find the hammerstones was very easy, rounded cobbles of all practical sizes were available. It was also easy to use a large flat rock at the
riverside to serve as an anvil.
(b) The experiments
I took a piece of quartz with dimensions 9x7x4 cm and striked it with a piece of (by the river-) rolled granite on the edges to get a handaxe type form( cordiform /pointed oblong). I realised, the blank* could only provide a pointed tool without cutting edges. After strong strikes on the edges, the debitage showed flakes, some of them were useful to get further adaptation ( dependent on the thickness, e.g. to serve as a possible mini- quartz points ). After this free- hand striking, I placed the object on a flat rock and carefully striked the edges to get the desired shape. I made a ( very) sharp point at one side. The result was a possible useful quartz handtool, with a solid, handshaped, ergonomic grip, with at the other side a very sharp point, to drill, press, etc. The tool was made in ten minutes.
|Front side of the pointed quartz|
|Back side of the pointed quartz|
A second piece of triangular shaped quartz ( ca. 7 x 7 x 4 cm) was only adapted to get two (convergent) sharp edge's to become a handtool such as to clean skins,scrape meat from bones , etc. The edges were sharpened by hammer-anvil technique, striking and pressing at the backside of the edge. The edge became rounded, but sharp, at least sharp enough to be a possible scraping tool.
A third tool was made from a quartz cobble with patina's ( dimensions ca 12 x 8 x 3 cm). The original shape was good enough to try to make a rough handaxe with point and one sharpened edge. This was partially successful. The rough shape was ready in 10 minutes.
A fourth tool was made by hard striking with a round granite cobble on a larger quartz piece, a large blade- like flake was produced in this way and later it was secondary retouched. This tool was very sharp, easy to use and easy to be secondary retouched.
|It does not look nice, but it is a quartz flake. Obvious not taken form a rounded quartz pebble. The cutting edge is very sharp.|
Main remarks in ad- hoc processing the quartz to become a ( disposable) (hand-) tool:
- Frost ridges and other invisible damages are ( as expected) important for the quality of the quartz; the moe white/ translucent the quartz, the better quality
- Small pieces of quartz ( debitage waste) are frequently good enough for further adaptation, especially when they are thick ( ca 2-3 cm)Lots of small pieces however are not re-usable, so handtool production seems logic (4)
- (Rounded) granites are very suitable as hammerstones
- Edges are not difficult to sharpen, and do not break easy
- Patterns of striking are recognisable on the tools edges as small, overlaying edges of shallow pits
- Secundary retouche with smaller hammerstones on pre- adapted edges is useless
- Reducing in size is easier than reducing thickness.
- Retouch on quartz artefacts is visible as rounded, towards the edge's point processed adaptation, made by striking and pressing techniques
- Processed quartz – as a tool- is visible by a 3D adaptation, where more than one part of the quartz has been adapted , so the adapted side has been – re- adapted in another direction
- Pointed retouchoirs of granite could help to get better notches or rounded forms on edges
- rolled quartzite was absent in all experiments at the Tarn
* blank: a raw shape of the quartz block, non -defined, but denouncing the limits of the process