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Abensberg-Arnhofen

Material name: Tabular chert of the Abensberg-Arnhofen type
Synonyms: Plattenhornstein, Bavarian tabular chert, chert of the Abensberg-Lengfeld type, Upper Jurassic chert from the Abensberg-Pullach basin
Material (geologic): Upper Jurassic (Tithonian/Malm ζ 1-2) chert

Detail of typical plate
Foto: Matthias Rummer, 2001

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General characteristics

(In part adapted from Engelhardt & Binsteiner 1988, Binsteiner 1990a and Rind 2000a
 

Geographical setting: The sources of Tithonian chert of the Abensberg-type are confined to the southernmost Upper Jurassic basin of the Franconian Alb, the so called "Abensberg-Pullacher Wanne". It is one of the few isolated areas with Jurassic sediments that lie on the right bank of the Danube and strictly speaking don't belong to the Franconian Alb sensu stricto, but to the Tertiary hills that stretch towards the South and the Alpine foreland. During the Palaeogene most of the Jurassic and nearly all of the Cretaceous sediments in the area were eroded away and the resulting basin was covered in the Miocene with freshwater-limestones and most notably sands and gravel of the Alpine Molasse (Meyer et. al. 1994).
The landscape is accordingly less spectacular than the Franconian Alb proper to the North with its steep limestone cliffs and deep valleys. The major exception to this is the "Weltenburger Enge" between Weltenburg and Kelheim, where the Danube has forced itself a way through the limestones, forming a magnificent gorge, making one of the best sights in the region. The area around Abensberg itself is rolling hilly country only occasionally interspersed by some higher hills which hardly surpass the 400 meter mark.
Material and colour: Strictly speaking, the name of Abensberg for this type of chert is wrong. Analogous to Baiersdorf, the material should be called chert from the Abensberg-Pullach basin or "Abensberger-Pullacher Wanne-type" as its occurrence is restricted to and its formation narrowly linked with this small Upper Jurassic (Malm ζ) basin.
In the archaeological literature, however, the name is so well established, that it would be quite impossible to change it now. When using the term, it should be restricted to the typical tabular banded chert ("Plattenhornstein"), as this is the only material from this source that can be distinguished macroscopically with any certainty from other cherts from the Franconian Alb.
  Core of typical tabular chert
Foto: Matthias Rummer, 2001
 
Small core of tabular chert from a Middle Neolithic context
Neolithic blade of Abensberg-chert
Foto: Matthias Rummer, 2001
 
Long blade of typical Abensberg-chert from an archaeological excavation in Dresden (Eastern Germany)
  Both specimens depicted above come from archaeological excavations some 300 kilometres from the source and were found in Neolithic pits (Elburg & van der Kroft 2001). We selected those pieces as they are the best proof of which material was distributed over long distances. Both are of the typical tabular variety with a thickness of slightly more than a centimetre but with significant differences in colouring. The small core (greatest length 29 mm) is somewhat atypical with a nearly homogeneous light grey core and only a single darker band under the cortex. The long blade (93 mm) shows the typical banding but is a bit more brownish than most specimens we collected at the source in Abensberg.
Apart from the banded tabular variety, which is without a doubt the best quality of chert from the district, nodular forms ("Knollen") as well as flattish nodules ("Fladen") occur too. All materials have in common that they are grey, from a very light to nearly black, and they do show some signs of banding or zoning. The banding can be very slight, especially with the lighter coloured materials and the nodules, or very pronounced. For examples of most varieties, see below.
Other information: Until now, there is only one extraction-area known for the Abensberger-Pullacher Wanne, being the name-giving site of Abensberg-Arnhofen, where a mining field was discovered in the 1980's and has been the subject of intermitting excavations ever since. The pits cover an area of at least 20 hectares, but this number could still rise significantly as rescue excavations, aerial photography and geomagnetic survey indicate that the limits of the mining field have only been reached in the East and South.
Like indicated above, the geological history of the area is quite complex. The original parent rock of the chert has been eroded during the Palaeogene, leaving the resistant siliceous material, nodular and tabular alike, embedded in a layer of residual loam. In the following Miocene, the whole basin (Abensberger-Pullacher Wanne) was filled up with sand, which was then again partly eroded and topped up with Pleistocene terrace-gravels. To reach the loams with the desired chert, the prehistoric miners were forced to bring down shafts through the loose sands and gravels down to a depth of up to eight meters.
In previous digs, pits with diameters of around 2 meters were uncovered, but newest excavations show shafts of less than a meter wide (Rind 2000b). Unfortunately, the site is only insufficiently protected by the local monuments law and large parts are being destroyed by a gravel pit every year, making rescue excavations under less than favourable circumstances necessary. Luckily, the local archaeological service, in co-operation with the universities of Frankfurt and Cologne, have recently secured research funds to excavate at least parts of the menaced area in advance (Rind 2001).

Estimates of the amount of output and the time needed to bring down a shaft vary strongly, and have to work with a very insecure database (see above). Engelhardt & Binsteiner 1988 assume that digging an average shaft to a depth of 6 meters would have taken about 320 hours with prehistoric tools. With one shaft an estimated 11 kg of chert of good quality could be mined, of which less than 3 kg would have been of the typical tabular variety. This would mean that for every kilogram of chert 29 man hours were needed, counting only the typical tablets, this number would rise to a remarkable 120 hours per mined kilo. With an estimated size of 200 000 square meters for the mining district, this would mean a total output of 145 metric tons chert of which 35 tons would be the desired tablets, but depending on the size of the district this number could be easily doubled or even tripled. It is to hope that the new excavations in the area will bring more reliable data.

The dating of the mines is still problematic. Until now only one reliable date from one of the shafts has been published, giving a calibrated age of 4650 BC This correlates well with the most intensive use of this kind of raw material in the Middle Neolithic.

Knapping notes: Finding good material for experimental knapping is not easy. We had some material from the spoilheaps of the gravel pit at our disposal of very varying quality. The coarser material, mostly nodules and thick tablets are quite worthless, but the finer material knaps very well. Especially the thin tablets with a thickness of 12 to 15 millimetres are very easy to work. After preparing a primary ridge on one of the sides, you can detach quite a number of blades without further preparation apart from some dorsal reduction. If you produce a hinge, you always can turn the tablet around and either remove the hinge scar from the opposite side or use the damaged face as a platform. The finer nodular material (Knollen and Fladen) is very nice to work too, giving beautiful patterned flakes and blades. All in all, we can imagine why Neolithic man did go to such great lengths to obtain this raw material.
Archaeological description: Thanks to intensive work by several scientists, the archaeology of this type of material is quite well known. The oldest artefacts made from this material, two hand axes (Rind 2000b) date to the Middle Paleolithic. Finds from the typical chert from Abensberg are also known from the Upper Paleolithic and Mesolithic, but it only gets really popular at the beginning of the Neolithic. Within the home range radius of the settlements around the mining district it is the most popular material, the tabular as well as the nodular variety (Davis 1975, but especially de Grooth 1994 and 1997c).

During the Middle Neolithic (Stichbandkeramik, Großgartach, Oberlauterbach and the Südostbayerises Mittelneolithikum, mostly known for its rude acronym SOB) the tabular chert form Abensberg-Arnhofen is one of the major long-distance raw materials in the whole of Central Europe. Lithics form this source have been found from Switzerland in the West to Eastern Bohemia and Moravia in the East. Towards the Northwest, single finds are known from Western Germany and recently the first finds of this material have been recognized in Middle Neolithic context in Eastern Germany (see above). Until now, the Alps seem to form the southern border of the distribution, something that reflects probably the historic situation: The transalpine transport of flint, especially the material from the Northern Italian sources of the Monti Lessini, is known only from the Late Neolithic, as the popularity of Abensberg-Arnhofen has declined and it is used on a local scale only.
There is an ongoing debate if the mining was done by (part-time) specialists who exploited the chert for strictly commercial purposes and were involved in long-distance direct trade (Engelhardt & Binsteiner 1988, Binsteiner 2000) and those that see indications of a free-for-all access with the distribution being of the down-the-line type (de Grooth 1994). The latter model would certainly be a lot more consistent with everything we know about the Early and Middle Neolithic, but detailed analyses in a large region would be necessary to decide between the two. It is to be hoped that the new research excavations in the mining district will at least shed some more light on the possible specialization of the mining and the production of roughouts/pre-cores on the site.



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Abensberg-Arnhofen
Locality: Abensberg-Arnhofen, Kelheim district, Bavaria, Germany
Synonyms: Kiesgrube (Gravel pit) Buchenrieder, Kiesgrube (Gravel pit) Brandl, Abensberg-Offenstetten; mining site D 5 according to the catalogue of the museum in Bochum, 3rd edition (Weisgerber et al. (eds.) 1999).
Geographical description: The prehistoric mining district of abensberg-Arnhofen is situated, like the name suggests, between the small towns of Abensberg and Arnhofen in Lower Bavaria (Germany), about 75 kilometres North-Northeast of Munich and 25 kilometres Southwest of Regensburg. The parts that have been excavated lie at the northern edge of a wooded area, directly to the East of the B16 road which leads from Ingolstadt towards Regensburg. Areal photographs however, show the site to extend quite a stretch towards the West (Rind 2000b).
The site itself is not much to look at, as there are no signs visible of the pits at the surface and large parts are being eaten away by gravel pits which are being filled back with rubble and rubbish.
Geographical co-ordinates: Lat. 48° 49' 27" N
Long. 011° 52' 54" E
(Mapdatum WGS 84)



click here for a detailed topographical map (51 KBytes). or here for a map with further sites in the Regensburg region.
Co-ordinate precision: The co-ordinates given above were taken with a hand held GPS receiver in the gravel/sand pit where some of the shafts were being cut by the workings as we visited the site in the spring of 2000. The districts covers at least 20 hectares and lies mainly to the North and West of the coordinates given.
Other topographical information: To reach the site, leave the motorway A93 which connects Regensburg with Munich at exit 49 which is appropriately called Abensberg. Follow the local road to Abensberg in the West past Scheuern and Ofenstetten. Just before this road connects with the North-South running B16, there is a field road that goes off to the North, running parallel to the B16, turn in there.
After about 1 kilometre, the road curves slightly to the East. This is at the southern edge of the detailed map above. After 200 meters, there is a fork in the road of which you take the left branch. Following this road for another 300 meters, you come to a further fork where you go to the right. The sand and gravel pits around here is where the mining pits are being uncovered until approx. 2005.
Additional information: Plan view of one of the mining shafts
Foto: Rengert Elburg, 2000
  We have to apologize again for the quality of the site photo. This is another picture off one of the films that some idiots at the local lab put in the wrong developing tank. What you see is one of the shafts, refilled with the white sands of the Miocene Molasse where it cuts through the brown Pleistocene gravels. The geological hammer (with some difficulty to be seen on the right) is about 30 centimetres long, showing that it is one of the narrow shafts in the newly excavated part of the mining field.
We had some other nice pictures of shafts cut by the gravel pit and an overview of the excavation area too, but after the unkind treatment they received in the lab and jpeg-compression, they don't deserve to be published here. Although we planned to visit the new excavations in 2001, we never made it because of our own field-work some 300 kilometres away. We hope there is a possibility to visit the site again in one of the next seasons, if the excavations are still going on.
Visitors information: The next place to find somewhere to stay and/or just a beer or a coffee is Abensberg, a very pleasant and well-preserved small town, supporting an astonishing amount of hotels and pubs for a place its size. For more information see the homepage of the town (alas, in German only).
During our excursion in the region, we stayed in Kelheim, very centrally situated for all sources in the region, about 10 kilometres to the North, something we can very much recommend. For further information on the infrastructure on this site, click here, or visit the (flash-heavy and only in German) homepage of Kelheim.
Sampling information: This is a tricky one. On the one hand, the backfilled prehistoric shafts are being destroyed by gravel pit and could be sampled without any burden to your consciousness, apart from trespassing into the sand works. On the other hand, as professional archaeologists, we can't write here that it's all right to go and loot a prehistoric site, even if it's threatened. As we visited the site during our very compact tour of Southern Germany, it was a Saturday and nobody to be seen. We had a look at the uncovered shafts that had been documented by the local archaeological service, took a few photos and filled a zip-lock bag with a representative sample of chert from the reworked spoil in the sand-pit. We can live with what we did and don't wake up at night bothered by feelings of guild.
As regular excavations are being carried out now, we would urge you to contact the responsible archaeologist of the archaeological service (Kreisarchäologie Kelheim), Dr. M. Rind, before you visit the site and might get yourself in serious trouble.
  Typical chert of the Abensberg-Arnhofen type
Foto: Matthias Rummer, 2001
 
Thin plate of typical Abensberg-type
striped tabular chert
Macro picture of Abensberg chert
Foto: Matthias Rummer, 2001
 
Macro-photo of a small flake of chert
  plate of chert from Abensberg
Foto: Matthias Rummer, 2001
 
Thicker tablet of banded chert from Abensberg
Flake of lighter material
Foto: Matthias Rummer, 2001
 
Very light coloured chert from the prehistoric mining site
Sample description: In sampling this site we naturally concentrated on finding good and typical tabular material, as this is the real long-distance material to be found up to 400 kilometres from the source. In the top row above you see on the left hand side a very nice tablet with the typical and pronounced banding. The thickness of the plate is quite exactly 10 millimetres.
The small flake next to it was detached from this tablet and has a width of ca. 15 mm. Click on the thumbnail to get a good impression of the very finely banded structure of this typical piece.
On the second row there is a fragment of a thick plate (20 mm) of good quality with pronounced banding and next to it a flake of a very light flattish nodule, one of the so called Fladen.
The two specimens below are more of a curiosity to show that not all material from Abensberg is so nicely patterned and of high quality. The left piece is another Fladen, but very dark. The impression of coarseness is mostly caused by patination, in the core it is still quite good material. The nodule on the right, on the other hand, hardly merits to be called chert. It is very coarse, partly crystalline and has a very uneven fracture.
  Plate of coarser materiale
Foto: Matthias Rummer, 2001
 
Example of Fladenhornstein from Abensberg-Arnhofen
Nodule of atypicl coarse chert
Foto: Matthias Rummer, 2001
 
Low-grade nodule (Knollenhornstein) from the same secondary deposit


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Galgenberg
Locality: Galgenberg near Abensberg, Kelheim district, Bavaria, Germany
Synonyms: N/A
Geographical co-ordinates: Lat. 48 49' 38" N
Long. 011 51' 18" E
(Mapdatum WGS 84)



click here for a detailed topographical map (51 KBytes). or here for a map with further sites in the Regensburg region.

Additional information: This site is included more for completeness than for anything else. The Galgenberg, a lowish hill rising to a bit over 400 metres asl., lies directly to the North of the town of Abensberg. Geologically it is situated at the western edge of the Abensberg-Pullach basin, the geological structure where during the Upper Jurassic (Malm ζ), the high quality chert of the Abensberg-type was formed.
We visited the site as it is mentioned in Binsteiner 1990b as a source of chert with tabular material as well as nodules. Although we did a extensive survey of the whole hill as we visited, nothing much was to be found on its surface. Only at the coordinates given here and shown on the detailed map we found some material worth collecting. We don't know if the material comes from the dircet subsoil or if it was washed down the slope. Probably this site can be considered a residual deposit at the best.
  Patinated flake of typical chert
Foto: Matthias Rummer, 2001
 
Slightly patinated flake of nodular chert from the Galgenberg
Piece of striped material from Galgenberg
Foto: Matthias Rummer, 2001
 
Banded chert with rusty spots from plough-scratches, surface find.
Material and colour: All stones we found here were natural pieces of nodular material, most of the heavily patinated. The piece on the left is a fragment of a small nodule, the flake being 4 cm wide. It is strongly patinated, with the weathering obliterating most of the internal structure.
The other piece is, judging from the cortex and banding, a fragment of a flattish nodule (Fladen), its greatest dimension is only 33 millimeters. It is a bit less patinated, but has been lying for quite some time in the topsoil as you can see from the rusty spots, caused by plough-scratching.

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Linsberg
Locality: Linsberg near Abensberg, Kelheim district, Bavaria, Germany
Synonyms: N/A
Geographical co-ordinates: Lat. 48 49' 42" N
Long. 011 51' 29" E
(Mapdatum WGS 84)

The co-ordinates given above are those of the site marked on the detailed map. We found some quite good material on other locations scattered all around the Lindsberg-hill, e.g. at the eastern slope around 48 49' 52" N/ 011 51' 44" E too, so having a look around might be worthwhile.



click here for a detailed topographical map (51 KBytes). or here for a map with further sites in the Regensburg region.

Additional information: View of the Linsberg taken from Galgenberg
Foto: Rengert Elburg, 2000
  Again a site only mentioned in Binsteiner 1990b as a probable source of chert. We visited the place to see if it could add something to our knowledge of the material from the Abensberg-Pullacher basin, which it couldn't. In the picture above you look from the Galgenberg towards the southwestern side of the Linsberg. The view is quite characteristic for the whole area: slightling ondulating with some lowish hills, like the Linsberg, which reaches a less than spectacular 407 meters above sea level in the middle of the photo. The samples come from the field in the middle distance on the southern side of the hill and more to the Northwest, that is to say, the side that faces towards the actual basin and the mining district of Abensberg-Arnhofen.
  Flake of typical fine banded chert
Foto: Matthias Rummer, 2001
 
Flake of typical fine banded chert
Piece of striped tabular chert
Foto: Matthias Rummer, 2001
 
Piece of striped tabular chert
Material and colour: Like you can see from the pictures, it is clear that we're somewhere near the source of the Abensberg-type chert. The piece at the right hand side above (width 34 mm) is a fragment of a tablet or very flat nodule with clear banding. With its fine structure, it is very similar to the high-quality material from Abensberg itself. The tree centimetres wide flake next to it was detached from flattish Fladen-type nodule, it is very fine and translucent at the edges.
The (prehistoric?) flake left in the bottom row is 25 mm wide, very fine and only very slightly translucent at the edges where the thickness is well under 1 mm. Judging from its internal structure, it comes from a nodule. All three pieces were found on the eastern slope.

The last piece is clearly a fragment of a thick tablet (max. thickness 27 millimetres), quite similar to the material from Abensberg itself, but internally flawed and of a medium-fine structure we didn't see in our sample from the mining district.

  Flake of very light material
Foto: Matthias Rummer, 2001
 
Flake of very light material from the Linsberg
Piece of coarser material from Linsberg
Foto: Matthias Rummer, 2001
 
Piece of coarser material from Linsberg
 

Last modified on:
February 9, 2002
Contents primarily by:
Rengert Elburg
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