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Wommersom quartzite

Material name: Wommersom quartzite
Synonyms: Wommersom kwartsiet, Grès-quartzite de Wommersom (GQW)
Material (geologic): Paleocene (Tertiary, Paleogene) cemented quartzite

Detail of wommersom
Foto: Matthias Rummer, 2001

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General characteristics

(In part adapted from Gendel 1982

Geographical setting: The only known outcrop of this material is located near the eponymous village of Wommersom in the Brabant province of Flanders, Belgium, some five kilometres east of Tienen. The southwestern part of the village lies on a low ridge, the Steensberg, which contains the quartzite. It is nowhere exposed, but smaller and larger blocks can be found on the surface of the fields in the neighbourhood. The region around Tienen is known as the Hageland, low, undulating country, mostly covered in Loess, which is drained by several small southwest-northeast flowing rivers. It is also the southernmost part of Dutch-speaking Flanders, just a few kilometres to the south lies the language boundary with Francophone Wallonia.
Material and colour: According to the Geological map of Flanders, sheet 33—St. Truiden, the quartzite is part of the Upper Paleocene Tienen Formation. Most of the material belongs to the Tienen Quartzite-facies (Kwartsiet van Tienen), which is a well-sorted cemented quartzite with a grain size between 150 and 175 µ (Nijs & De Geyter 1984).
The Wommersom Quartzite in contrast, has a more porphyric structure with isolated larger quartz grains in a very dense matrix. With the naked eye or a hand lens with lower magnification, the matrix seems to be quite amorphous, but isolated quartz grains can even be discerned very well macroscopically (picture below).
  Detail of Wommersom
Foto: Matthias Rummer, 2001
Close-up of the typical Wommersom quartzite.
Note larger, isolated grains in fine matrix.
  Plane polarized light
Foto: Marlina Elburg, 2000
Thin section under plane-polarized light.
Field of view: 9 mm.
cross polarized light
Foto: Marlina Elburg, 2000
Thin section under cross-polarized light.
Field of view: 9 mm.
  In thin section under plane-polarized light, not much detail is gained, but in cross-polarized light you can see clearly the matrix consisting of very fine grains of crystalline material (under 30 µ), cemented with microcrystalline quartz, as opposed to e.g. the very fine quartzite from Skršin, where the amorphous matrix looks black in cross-polarized light.

The colour is predominantly dark grey to dark greyish brown (2.5Y 4/1-4/2), sometimes a shade lighter, and with a bit more of chroma. The lighter mottling is mostly grey to light brownish grey (N6 to 2.5Y 6/1-6/2), sometimes tending a bit more towards brownish yellow. The cortex is mostly very thin, well under 1 mm, but can in some pieces reach a thickness of nearly a centimetre, and has a 'sandpapery' feel to it.
Wommersom quartzite is susceptible to patination, notwithstanding the crystalline structure, which can render it completely white, but even then an identification is mostly possible based on the typical structure.

Other information: Although the material is very well known in the wider region, no real research has been done on extraction and exploitation at or near the source. Some kind of more or less organized exploitation must have taken place, regarding the frequency of the material on Mesolithic sites in the wider region. No extensive workshops with large amounts of tested and discarded material that would be typical for an exploitation/extraction site are known in the immediate vicinity. It has been suggested that extraction has taken place on parts of the outcrop that now have vanished, or aren't accessible any more (Rozoy 1971).
Knapping notes: Wommersom quartzite is a material that could be classified as 'forgiving'. Its not-too-fine matrix with dispersed larger grains causes quite "flat" fractures without a pronounced bulb of percussion, and low brittleness. You can work it perfectly with hard percussion without crushing your platform, and even end up with quite thin flakes. The fracture runs smoothly, and follows ridges well enough to produce regular blades and bladelets. The only disadvantage is a slight tendency to produce hinges. In the only overview of technological properties of the material nearly 25% of the debitage where the distal end was present, it ended in a hinge (Van Oorsouw 1993).
Another good point for enthusiasts of experimental archaeology: with a piece of marcasite it gives great sparks for lighting your genuine Stone Age fire.
Archaeological description: From an archaeological point of view, Wommersom is an ideal material for distribution-studies. There is only one known source, it is a good raw material in a region without much other sources of lithic materials, and it is quite easy to recognize.

The quartzite is used occasionally already in the Middle Paleolithic, e.g. in the cave of Spy, 40 kilometres to the south-west, but the most extensive use dates to the Mesolithic, especially the later part of this period. In Northern Belgium (especially in the provinces Limurg and Luik/Liège) and the southern part of the Netherlands (provinces of Brabant and Limburg), it can be regarded as a 'guide-fossil' for the Late Mesolithic.
Unfortunately, there haven't been any in-depth studies about the distribution of the material yet, but some general overviews outline the extend of its use well enough. The distribution area seems to be bounded by the rivers Meuse in the east, the Scheldt in the west and the Rhine in the north. The southern limits of distribution seems to coincide with the Franco-Belgian border, but it is not clear if this is an artificial boundary (Gendel 1982).
More or less occasionally, the material is found in other regions, like the German Rhineland between Meuse and Rhine (Arora 1979 and 1980), and on the Dutch Veluwe (around the city of Apeldoorn in the centre of the Netherlands, Van Oorsouw 1993), with a few pieces further to the northeast.
Based on this distribution, covering an area of approx. 40.000 km2, as well as the occurrence of some types of microliths (see below) it has been proposed to see this region as the "social territory" of a dialectic tribe (Verhart & Arts 2005).

Wommersom quartzite is used for all types of debitage and instruments, although there seems to be a slight preference for the production of blades, and tools made thereof, like microliths. There seems to be some correlation between the frequency of the use of the material and the production of some types of trapezes and surface-retouched microlithic points like the feuille de gui.
Apart from knapped tools, there are very rare cases where Wommersom Quartzite was used for the production of Late Neolithic tools like polished axes (e.g. Van der Graaf 1990).

Thanks and acknowledgements: Special thanks to Marie-France van Oorsouw, who made her unpublished master's thesis on the distribution of Wommersom quartzite in the Netherlands available to us.

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Locality: Wommersom-Steenberg, Linter municipality, Brabant, Flanders, Belgium
Synonyms: FlintSource sample 120.
Geographical description: The village of Wommersom lies five kilometres east of the city of Tienen in Flemish Brabant, Belgium. It is the only known source of this type of lithic raw material.
Geographical co-ordinates: Lat. 50° 48' 29" N
Long. 005° 00' 45" E
(Mapdatum WGS 84)
Co-ordinate precision: Rodestraat in Wommersom
Foto: Rengert Elburg, 1999.
  The coordinates point to the end of the 'Rodestraat', seen in the picture above, at the southwestern side of the village, where we collected most of our material. Taken with a hand-held GPS-unit in quite open country they won't be off by more than a few metres. Mind you: there might be spots were more material is present, but as we visited the source, we didn't do a intensive survey of the area.
Other topographical information: Wommersom is perfectly connected to the logistical infrastructure, as long as you have your own means of transport: it lies just of the N 3, which connects Tienen with Sint-Truiden. If you come from further away, the easiest road to follow is the A 3/E 40 motorway, which runs between Luik/Liège/Lüttich and Brussels, leave it at Tienen, turn east to Sint-Truiden before you enter the city, and you will find yourself on the aforementioned N 3. After approx. 4 kilometres a signposted road leads to the north and Wommersom. In Wommersom, just stay on the ridge, in the direction of Oplinter.

If you want to do some surveying in the area, it is a good idea to bring a detailed map, like the readily available 1:50 000 topographic map of the NGI/IGN, of which you will need sheet 32.

Additional information: Sampling location southwest of the village
Foto: Rengert Elburg 1999
  If you are looking for spectacular vistas and overwhelming natural beauty, Wommersom is clearly not the place to go. Here you are looking from the slight ridge on which Wommersom is located towards the southwest. Most of the surrounding area looks quite similar, with ploughed fields, some trees, and quite a lot of farms and villages.
Visitors information: If you are visiting the area, it probably is best to stay in Tienen, which is a very nice smallish town with a few places to stay, and ample infrastructure in the way of eating and drinking. There are two specialities in the region you shouldn't miss. The first is something of a curiosity, namely the wine. The Hageland is one of the northernmost wine-growing areas, and the only official one in Belgium. Most wines are white and come from a wide range of grapes, among others Chardonnay, Riesling, Auxerrois, Kerner, Bacchus, and the inevitable Müller-Thurgau, but also a few 'northern' red varieties like Limberger, Dornfelder and Pinot-Noir are being cultivated.

More important are the beers, of which some of the best in Belgium originate in the area. The best known brewery is of course 'De Kluis' in Hoegaarden, with its famous white wheat beer, Hoegaards Witbier, a light, fruity beer that is ideal drinking on hot afternoons. Some other beers from this brewery are Hoegaarden Grand Cru, a strong, tripel-type beer, and Verboden Vrucht, a very strong, slightly sweetish dark beer, perfect to warm you if you visit during the winter. Sadly enough, the owner of the brewery, InBev has decided to close it, and move the production to its industrial plant at Jupille. We very much hope this won't influence the quality of the beer, as it used to be among our favourites.

Sampling information: As there is no exposure with the material in situ, you will have to collect your sample from the surface. This means you are limited to ploughed fields, and the like, so it is best to come during the period between late autumn and early spring. The pictures on this page were taken in April 1999, and as you can see, the conditions were quite perfect to gather some material.
As usual, don't take more than you need, don't start collecting cultural material, and limit knapping in the area to testing the blocks you want to take. This is a unique source, so do not over-exploit it.
We are of course very much interested in any information on mining, exploitation, and processing of the material, as well as seeing the stuff in an exposure. So if you have any information on these aspects, please get in touch.
  Typical flake
Foto: Matthias Rummer, 2001
Flake of typical dark Wommersom-quartzite with lighter mottling.
Size: 43 mm.
Blade of Wommersom kwartsiet
Foto: Matthias Rummer, 2001
Freshly struck blade; note silky reflections by fine quartz grains in the matrix.
Length: 46 mm
  flake with isolated quartz
Foto: Matthias Rummer, 2001
Wide flake with clearly visible larger grains of quartz.
Size: 32 mm.
Sample description: The three pieces figured here should be enough to give you a good impression of the typical Wommersom quartzite, but beware: it is one of the few quartzites that are susceptible to patination, so archaeological finds can look very different!
For further description of the material, see above.


Last modified on:
July 18, 2006
Contents primarily by:
Rengert Elburg
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