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Material name: Upper Jurassic chert from the Franconian Alb
Synonyms: Hornstein, Knollenhornstein
Material (geologic): Upper Jurassic (Kimmeridgian-Tithonian/Malm ζ) chert

Detail of flake from Herrnsaal
Foto: Matthias Rummer, 2001

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General characteristics

(In part adapted from Binsteiner1990band Meyer et. al. 1994

Geographical setting: The sites of Herrnsaal and Kelheimwinzer lie to the west of Kelheim on the left bank of the Danube. They belong to the Kelheimer Wanne, one of the numerous Upper Jurassic basins in the area. The occurrence of these cherts is linked to a very narrow band of Upper Jurassic sediments that stretches between Kelheim and Herrnsaal.
Material and colour: The chert from this small area is very much of the generic "Franconian Alb"-type, as it can be found in quite a large area of Southern Germany. The colour varies from white (N8), light gray (N7 and 2.5Y 7/1), and very pale brown (10YR 7/3) to gray (N6) and bluish gray (5PB 6/1). Nearly all material shows slight banding, but not as pronounced as some other materials from the region. The structure is mostly medium to fine grained with a relatively soft and thick cortex. Judging from what we have seen the material can occur in nodules as well as in quite thick banks.
Other information: Chert embedded in parent rock
Foto: Rengert Elburg/Paul van der Kroft, 2001
  The most important point for the site at Kelheimwinzer is that is one of the very few sites in the region where the Upper Jurassic cherts can be found in a primary context. Most sources, especially those used in prehistory, lie in residual loam. The sample shown above is a large block of limestone with a good sized band of chert in it. After having seen how the siliceous material is embedded in the very dense and hard limestone, you can imagine why the Stone Age miners preferred to get their material in a weathered-out form. Even with a very good geological hammer it is nearly impossible to separate the chert from the limestone without smashing it to pieces.
Knapping notes: As the material is not too fine, it is very easy to knap without much preparation of the core or strike platform. The fractures run well and don't give a very pronounced bulb of percussion. On the other hand, the edges are not very sharp, but seem to be quite stable. the material is suited for direct hard and soft percussion, but less for pressure flaking. In all it is quite nice to work, but nothing very special.
Archaeological description: Nothing is known about the archaeology of these sites or about the use of this very generic type of chert in prehistory. Kelheimwinzer is only mentioned as an occurrence of chert in Binsteiner1990b, but we haven't found anything else about this source in the archaeological literature.

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Locality: Herrnsaal, Kelheim district, Franconian Alb, Bavaria, Germany
Synonyms: N/A
Geographical description: Herrnsaal is a villages on the left bank of the Danube, 5 kilometres East of Kelheim in Bavaria, Germany. The sampling site lies to the West of the village and is the easternmost point of a narrow ridge of Upper Jurassic limestones, covered in residual loam with some chert in it.
Geographical co-ordinates: Lat. 48° 54' 34" N
Long. 011° 56' 27" E
(Mapdatum WGS 84)

click here for a detailed topographical map (44 KBytes) or here for a map with further sites in the Regensburg region.
Co-ordinate precision: The coordinates given are for the southern edge of a field where it slopes down with a slight step towards the Danube. Most of the material comes slightly to the North of the coordinates given.
Other topographical information: The sampling site lies just south of the local road that leaves Kelheim towards the east. For further information, see the detailed map above.
Additional information: The site is not much to look at, just some fields to the West of the village of Herrnsaal, hence no site picture.
Visitors information: During our excursion in the region, we stayed in Kelheim, the not-too-large town at the confluence of the Altmühl and Danube. Although the place is on the first sight not too spectacular, it is very central to the different sources of chert in the region and has a reasonable infrastructure. There are several hotels, a museum, and a tourist information that seems to close in the moment we enter the town.
We stayed a few days at Hotel "Weisses Lamm", which is a typical German place at the western side of the town centre. Not cheap, but not very expensive either, with decent regional food of the type the Germans call Gutbürgerlich, a term that is impossible to translate, but means normal, down-to-earth German cuisine. The beer they serve, Thurn und Taxis, is not our favourite, but still quite drinkable. There are several other places to stay, which didn't look too bad either, it was just that we happened to go to this place first and they had a room available.

A good place to go for a beer and a bite is the brewery at the eastern side of the centre. Their lighter Weizen-beer is good, but nothing special, but they make a strong beer called Aventinus that is really worth sampling. We had a dinner of suckling pig cooked in this beer, with a few pints of the stuff to keep the enormous amount of meat down. Getting back to the place where you are staying can be a bit of a problem after an evening in this place.

Strong beers have a very long tradition around here. In the monastery of Weltenburg, some five kilometres to the Southwest of Kelheim, they have been brewing it for nearly a thousand years, and they really are good at it. The monastery is situated at the southern end of the Donaubruch, a narrow meandering gorge cut through the limestones by the Danube. It is only a short drive out of Kelheim, but if you don't have a teetotaller on the team, better leave the car an go by boat. They leave from Kelheim and will drop you after a short trip along the Danube at Weltenheim, alas with hordes of tourists who make the same trip. Don't miss the last ship out, otherwise the hike back to Kelheim can be very, very long after a few pints of the monastic brew.

The museum in Kelheim is not too big but, as to be expected in the region, the do have a lot of flint and information (including a laquer-section of a shaft) on the nearby mining site of Abensberg-Arnhofen. But beware: they are open only from April 1st, and close probably somewhere in October.
Another curiosity near Kelheim is the 60 metre tall Befreiungshalle, high above the town, build by King Ludwig the Mad, the same guy who gave the Americans and Japanese their dream of an European castle with Neuschwanstein and well known crony of Richard Wagner. Not everybody's taste (at least not of those with their minds still intact), but worth the trip because of the view you get. For those among us interested in later prehistory: the thing was build in/on a Celtic fortification and on the nearby plateau there are ample traces of Iron Age ore mining.

Sampling information: All pieces showed here come from a field just to the West of the villages of Herrnsaal. Pickings are very poor and there are a lot of better places to go if you are interested in getting generic "Franconian Alb"-type chert, like Alling or Thalhof.
  Flake of chert with fossilized impression of the stalk of a crinoid
Foto: Matthias Rummer, 2001
Flake of chert with fossilized impression of the stalk of a crinoid
Piece of typical grey chert from Herrnsaal
Foto: Matthias Rummer, 2001
Piece of typical grey chert from Herrnsaal
Sample description: The piece to the left above (width 50 mm) is somewhat atypical for the region and reminds us more of the older, Upper Oxfordian (Malm β), material from Münster-Buchberg and similar sources from the Ortenburger Jura further to the East. The chert is nearly completely opaque, medium grained and contains a lot more fossils than any other material we found in the region. A nice detail is the impression of a crinoid in the very thick and chalky cortex. As it is a residual source, we can't rule out that it is actual older than the rest of the material from the region, but this seems unlikely as there are not outcrops of Oxfordian or even Lower Kimmeridgian anywhere near the site.
The piece next to it is a small flake (max. 35 mm) of very light, fine grained chert with a narrow dark zone directly under the relatively thick and soft cortex.
The piece below is a patinated flake 27 mm wide with clear banding. The colour of the bands is a bit brownish, which could indicate some infiltration by iron salts but could be original too.
  Slightly patinated flake
Foto: Matthias Rummer, 2001
Slightly patinated flake of banded chert

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Locality: Kelheimwinzer, Kelheim district, Franconian Alb, Bavaria, Germany
Synonyms: 3 Winzerberg, Kelheimwinzer.
Geographical description: The sample comes from a very small exposure at the southeastern end of the Lehnberg, just East of the village of Kelheimwinzer. Here some presumably Upper Kimmeridgian/Lower Tithonian (Malm ζ 1-2) chert bearing banked limestones are visible in the entry to a private home.
Geographical co-ordinates: Lat. 48° 54' 52" N
Long. 011° 55' 33" E
(Mapdatum WGS 84)

click here for a detailed topographical map (44 KBytes) or here for a map with further sites in the Regensburg region.
Co-ordinate precision: The coordinates given here taken with a handheld GPS-receiver just outside the entrance road to the house at Winzerberg 3. The exposure itself lies a dozen or so metres to the North.
Additional information: Exposure with chert bearing limestones
Foto: Rengert Elburg, 2000
  Sorry again for the quality of the picture, which was dropped in the wrong tank during developing. As it is the only exposure with chert of some quality we found during our visit of the region, we still include it to give an impression of what the site looks like.
Visitors information: See above
Sampling information: As this sampling spot is located directly on somebody's doorstep, be sure you ring before you enter. We had the luck that the inhabitant just arrived by car as we were looking at the exposure and were contemplating some serious trespassing. He didn't mind us taking two larger blocks of limestone with chert embedded in it lying at the foot of the wall.
  Flake of typical chert from the primary exposure
Foto: Matthias Rummer, 2001
Flake of typical chert from the primary exposure
Chert nodule still embedded in the parent rock
Foto: Matthias Rummer, 2001
Chert nodule still embedded in the parent rock
Sample description: The large flake on the left is a bit over 7 centimetres wide and shows fine grained, slightly banded light gray chert with a thick and hard cortex. The specimen next to it is a piece of coarse limestone with a small, medium grained nodule of chert without any visible cortex firmly embedded in it.


Last modified on:
February 16, 2002
Contents primarily by:
Rengert Elburg
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