2012-11-15

The deceptive effect of eluvium flint

At a field not far from the well known "Kaap"of Eijsden, at a part of an area konwn as "Schelberg, northeast of Eijsden, artifacts made of different flint types, were found( see image below).
The first flint type was the black one, obvious the ( local)  Rijckholt flint -type.
Than the light grey flint type, which is more more granulated was noticed,  obvious the Hesbaye flint- type, as we know from Lanaye - St. Pietersberg1 and 2 at the other side of the Maas.
Another remarkable find were flakes and small tools made of  the Orsbach- Vetschau flint -type. A very translucent flint type was also found at this field.So four different flint types has been used to make the tools.
Because they all look Neolithic, the first conclusion would be, these flint types were transported as nodules  from the original mining locations ( see for an oversight of these mining locations the regional lithograph library at this blog.
But here is the deceptive effect. All these flint types, except for the translucent flint,  once belonged to the local cretaceous bedrock. They belonged either to the chalk of  Lanaye  ( the origin of the Rijckholt flint) or to  the chalk of Lixhe.The dissolved chalk ( almost certainly dissolved by the river Maas that flew over the St. Geertruid terrace, more than 900.000 years ago) brought the flint types together in a palimpsest at the field. Prehistoric toolmakers used all kinds of  flint types, to make their tools.

In this way, the eluvium flint of the Banholtergrubbe was used by the early Neolithic farmers ( Brounen & Peeters 2000/2001)  but it is more likely slopes with exposed eluvium flint were well known by Palaeolithic and the (Late-) Mesolithic hunter- gathers.
The translucent flint type is most likely a fluvial flint, as we find  the gravels mixed together with the eluvium flint.
The evidence for such a palimpsest of  eluvium- flint was formed by a fossilized sea urchin found at the same field, at the location of the artifacts. Recognizable sea urchins are a regular part of eluvium flint, so are belemnites.
This sea -urchin is of the Orsbach black- white flint type.

- Flint from an elvium at Schelberg 1. Rijckholt flint type, 2 Orsbach - Vetschau flint type ( var grey) 3. Hesbaye flint type. 4 Translucent brownish fluvial flint
Side view at the very altered sea urchin found near Rijckholt at the Schelberg, at an altitude of ca + 85 m.

- The bottom of the sea urchin showing the black/ white flint of the Orsbach -Vetschau type.
Retouched small flakes and  a small blade, possible Late -Mesolithic tools from the Schelberg, near Eijsden.
South of the Dutch community of Libeek at the Belgium border we find the Hoogbos. Here we find an elvium  flint type  with flint that has the same appearence like the Orsbach flint. Indeed, as this Orsbach type flint always  is looking  very fresh (compared to other flint types at the same location) , we probably deal with same elvium flint like at Eyserheide ( Sano, 2010), but in a later period ( between the late Magdalenian and the early Neolithic).  The eroded slopes of the Hoogbos area ( north south and west parts) were searched  by Palaeolithic and Mesolithic hunters. At these locations, where eluvium flint artifacts are visible, we also find microliths from the Mesolithic.
This would suggest, the search for microliths could best be focused at gravel rich fields and fields that contain eluvium flint. It is has been noticed by the author, microliths from the Mesolithic are abundant in the region, but scattered ( often we only find a few microliths together).
Finds like these underline the importance of knowledge of all flint sources in the region and the knowledge about the local eluvium flint locations.
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References

Bless, M.J.M. & Felder S, ( 1989) Notes on the late cretaceous of Hockai (Hautes FagnesNE Belgium) PDF  Annales de la Sociét;e Géologiede Belgique T 112/  47- 56

Bridgland, D.R. & Allen, P., (1996)  A revised model for terrace formation and its significance for the early Middle Pleistocene terrace aggradations of north-east Essex, England. In: Turner, C. (ed.): The early Middle Pleistocene in Europe. Balkema (Rotterdam): 121-134. 

Brounen, F.T.S., & H. Peeters (2000/2001) Vroeg-neolithische vuursteenwinning en -bewerking in de Banholtergrubbe (Banholt, gem. Margraten), Archeologie 10, 133-150.
Buurman, P.; Jongmans, A.G.; Broekhuizen, J.; Miedema, R. ( 1985) Genesis of the flint eluvium and related beds in South Limburg, The Netherlands;       Geol. Mijnbouw 64 (1985) 89-102  Laboratorium voor Bodemkunde en geologie (Laboratory of Soil Science and Geology)
Ham R. van der  (2000)  Zee-egels uit het vuursteeneluvium van Zuid-Limburg, de Voerstreek en hetAachener Wald PDF article in Dutch, Grondboor en Hamer 5
Sano, K.  (2010) Lithic functional analysis in :  [ Rensink, E.] Eysderheide, a Magdalenian open -air site in the loess area of the Netherlands and its archaeological context  Faculty of Archaeology Leiden  Analecta Praehistorica Leidensia 42

 








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