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Hárskút Radiolarite

Material name: Hárskút-type radiolarite
Synonyms: N/A
Material (geologic): Jurassic radiolarite

Detail of radiolarite from Harskut
Foto: Matthias Rummer, 2001

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General characteristics

(In part adapted from Bacskay 1995b and Trunkó 2000)

Geographical setting: Hárskú is a small village ca. 13 kilometres to the Northwest of Veszprém in Central Transdanubia, Hungary. It lies towards the centre of the Northern part of the Bakony Mountains, the Southern range of the Transdanubian Central Mountains. The area is hilly, partly wooded, partly cultivated, and lies at an altitude around 500 metres asl.
Material and colour: The material found here is known in the archaeological literature as Hárskút-radiolarite. It is a cryptocrystalline material, consisting mostly of quartz and was formed in Jurassic limestones. It has been described as being homogenous brown in colour, and typical for, but not restricted to, the occurrence at Hárskút. As we visited the site, we could confirm the predominance of dark brown material, around 7.5-10YR 3/2 (dark brown to very dark grayish brown), but we found a nearly proportional amount of very dark, nearly black material. Apart from these varieties, we found several pieces and blocks of red radiolarite, very similar to the red material from Bakonycsernye and the less typical variety from Szentgál. It seems that these red radiolarites, that don't show the typical structure of the Szentgál-type can be found all over the Bakony Mountains.

Like all higher-quality radiolarites from the area, the Hárskút-type is very fine with a silky to slightly greasy or waxy lustre and translucent only on the thinnest edges, but very frequently internally fractured. It can be very similar to the brown radiolarites from Tata (link to be added in the future), although those are mostly less shiny on the fracture. One author (Biró 1988) reports "orange lamellae on the broken surfaces and in very thin flakes", which we didn't observe in the material we found at Hárskút. The same publication shows on the map of lithic sources in Hungary three sites in the Bakony Mountains as well as one in the Gerecse Mountains (link coming up), where this type of material can be found.

To try to differentiate the different radiolarites from the region on a more objective basis, we had one typical piece made into a thin section, the results of which can be seen below. Probably a lot more can be said about those thinnies by a specialized sedimental petrologist, but this is the description of our own (volcanological) geologist Marlina Elburg:

"cryptocrystalline quartz with small colourless dots/grains, the matrix contains some finely dispersed brown and black crap. Some quartz veining."
If you compare these pictures with those of the material from Szentgal, you don't see much differences at this magnification. Even an enlargement wouldn't bring in much differences, as the material is of a very similar age and was formed in the same type of material. It might be that a very precise microfacial and/or micropalaeontological research could bring some clarification as geochemical analysis doesn't seem to work (Biró & Regenye 1991). See for further notes on similarities and differences the general section on the region.
For a full-blown picture of thin section,
click here (144 KBytes).

Field of view: 9 mm.
Thin section of Harskut radiolarite under plane polarized light
Foto: Marlina Elburg, 2000
Thin section of Harskut radiolarite under cross polarized light
Foto: Marlina Elburg, 2000
For a full-blown picture of thin section,
click here (134 KBytes).

Field of view: 9 mm. 
Other information: Although no excavations have been carried out on the site, there is clear evidence for prehistoric mining. In 1970, during a geological survey, several antler mining tools were found and in one section large amounts of debris resulting from the extraction were observed. Lacking further work on the site, we don't know anything about mining technique or about its dating.
Knapping notes: As we didn't locate any primary outcrops of the material, we were forced to do our experimental knapping with some small pieces from the surface. As you can see in the pictures of (some of) the specimens below, it has a good conchoidal fracture, but due to the heavy internal fracturing we couldn't produce a single decent flake. This might be caused by weathering on the surface, but as you can see in the thin sections, quite a lot of fractures filled with secondary quartz run through the material. We can imagine, that there are banks or nodules with very reasonable material, but in all cases, like with most radiolarites we saw until now, you will probably end up with a large pile of angular shatter. On the other hand, we must say that the radiolarites from here are a lot better than any other blackish variety we have seen until now. Mostly these are, compared to the red or green material from the same area, absolutely inferior and only produce small angular lumps, even if you get it in a fresh state directly out of the rock. This stuff at least looks like there could be useable material around.
Archaeological description: Hardly anything has been published about the archaeology and distribution of radiolarites of the Hárskút-type, apart from the short description of the mining site (Bacskay 1995b) and a note about the distribution in Biró 1988. According to the latter author, the distribution of the material is concentrated in the Transdanubian part of Hungary, with only sporadic pieces crossing the Danube into the Great Hungarian Plain. From the diagrams in Biró & Regenye 1991, can't be deducted if there is any particular period in prehistory when the Hárskút-type was especially popular.
We never heard of it being identified outside Hungary, so its circulation might be more restricted then the other important types of Transdanubian radiolarites, or it could be that the material is simply less know and therefore not recognized.


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Hárskút-Gyenespuszta

Locality: Hárskút-Gyenespuszta, Bakony mountains, Hungary
Synonyms: The site Hárskút-Édesvízmajor, which should be, following the description given in Bacskay 1995b, identical with our sampling site, is also known as mining site H9 according to the catalogue of the museum in Bochum, 3rd edition (Weisgerber et al. (eds.) 1999).
Geographical description: The place where we did most of our collecting is a bend in a track (see below) on a slight rise, about three kilometres Northwest of Hárskút. The narrow field-path runs just along the edge of the wood and there is a ruined farm which is indicated on the map as Gyenespuszta.
On the 1:40 000 there are three small quarries drawn in the immediate surroundings, of which two didn't contain any visible radiolarites, and the third one in the woods (which probably would have had something in it), we couldn't locate because of the oncoming darkness.
Geographical co-ordinates: Lat. 47 11' 47" N
Long. 017 46' 22" E
(Mapdatum WGS 84)
Co-ordinate precision: The above co-ordinates were taken with a hand held GPS-receiver at the spot where we collected most material. The co-ordinates given by Bacskay 1995b for the site of Hárskút-Édesvízmajor are 47 11' N, 017 49' E, placing the site somewhat to the East of Hárskút, in firm contradiction with the description of the site being approx. 3 kilometres to the Northwest of the village.
Other topographical information: Getting to Hárskút, and from there to the site isn't too difficult, but like always it's a good idea to bring a large-scale map. In this case you will need map number 2 "A Bakony, északi rész" (Bakony, Northern part) of the 1:40 000 tourist map series from Cartographia, to be bought for about 2 € in every bookshop or tourist-information.
Follow the highway number 8, which runs from Vesprém to the West to Márkó, which is a village about 6 kilometres West of Vesprém. Here turn into the main street to the North, which passes by the railway-station. After another 6 kilometres, just before you enter the village of Hárskút, there leaves a narrow, very straight road to the left (Northwest). This is also the starting-point of a trail marked with red signs, which gets you directly to the site. Depending how much you love your vehicle, or how much confidence you have in it, you can either leave it at the point where the tarmac runs out, or drive straight through to the large bend after which the track runs to the Southwest, along the edge of the woods. Around here you can find the dark radiolarites in abundant quantities.
Additional information: We visited the site only once, during our somewhat overloaded trip in the region in 1999. As FlintSource was only an idea at that moment, and we got to Hárskút in the beginning dusk, we didn't take a picture of the site. Not that you miss a lot, where we did our sampling, there was only a slight rising hillside, a track and either a view across some fields or a wood in the background to be seen.
Visitors information: Finding a place to stay in the area is something of a problem, to say the least. We tried our luck in Veszprém, which, being the centre of the region and a medieval city, we supposed to have an ample supply of nice and typical places to stay. This is clearly not the case. After getting there in the early evening, we first got thoroughly lost in a maze of one-way streets and roads that only led back onto themselves. After reaching the escape velocity necessary to get out of the labyrinth, we found ourselves somewhere to the Southwest of the city, where some place was signposted. Not caring about the uninspiring overpricedness of the setup, where we were the only staying guests, we spend the night there and had a meal that was in accordance with the atmosphere.
It is probably the best option to drive another few kilometres and find a place to stay near Lake Balaton. As this is the main touristic area of Hungary, finding something over there shouldn't be a problem, if you don't mind the hordes of tourists.
Sampling information: According to Bacskay 1995b, the site was found during geological fieldwork, which should indicate that there is an accessible exposure somewhere around. This might be the quarry indicated on the topographical map, but as the geological survey was carried out in 1970, the exposure might well have been grown over in the last thirty years. We collected the material on the surface, around the co-ordinates given above. There is a fair amount of material lying around here, occurring in a kind of concentration which could indicate mining, but we didn't see any worked material in form of flakes or the like. It seems our sample is fairly typical, so you might get the material from here as well.
For a full-blown picture of this sample, click here (66 KBytes). Flake of typical brown radiolarite
Foto: Matthias Rummer, 2001
Piece of blackish radiolarite from Harskut
Foto: Matthias Rummer, 2001
For a full-blown version of this picture, click here (54 KBytes).
For a full-blown picture of this sample, click here (63 KBytes). Slightly patinated material
Foto: Matthias Rummer, 2001
Reddish material from Harskut
Foto: Matthias Rummer, 2001
For a full-blown version of this picture, click here (78 KBytes).
Sample description: The piece at the left of the top row is typical for the site and has an homogenous colour of 7.5YR 3/2 (dark brown), without any macroscopically recognizable structures. The piece next to is plain black (2.5Y 2.5/1). On the right of the bottom row is a slightly patinated piece, 7.5YR to 10YR 3/1 (very dark gray) with some lighter spots. The larger piece on the right hand side of the lower row is shown more as a warning, radiolarites from all sources in the Bakony Mountains can vary quite strongly in colour at any source. The piece in the picture varies from 10R 4/3 (weak red) to 2.5YR 4/4 (dusky red), not unlike the material from Szentgál.

 

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