Speaker
Mr
Benjámin Váczi
(ELTE Department of Petrology and Geochemistry)
Description
In NW-Italy most of the Neolithic polished stone artefacts (axes, adzes, chisels) are manufactured from high pressure and low temperature metaophiolites – greenstones – but they widespread everywhere in Europe also [1, 2, 3]. In the last 10 years in Hungary 25 prehistoric polished stone tools were identified during the re-examination of the Museum historical collections [4]. The specialty of these artefacts is in their really uncommon raw material for East Europe until now. There are only few territories in whole Europe where we can find LT-HP metaophiolites in primary form: Monviso, Western Alps (near Torino)[5] and Syros and Tinos, Greece [6]. Na-pyroxenites, eclogites and their retrograde metamorphic derivates appear also in the Oligocene conglomerate on the northern side of Voltri [7] and in the recent alluvium of river Po, Curone and Staffora. The researchers agree in: the raw material of these artefacts originated from the W-Alps and the N-Apennines, but the precise source location is not specified so far. The aim of this research is to find significant difference between the potential source locations. We selected 3 possible source locations: the southern part of Monviso , the alluvium of Po, and the alluvium of Curone, to make a detailed petrographic and geochemical study to clarify the provenance of these special artefacts. During our work we analysed the samples by PGAA and SEM-EDX by electron-microscope to compare directly our results with the results of the earlier analysed polished stone tools
The main rock forming minerals of Na-pyroxenites and eclogites are Na-rich monoclinic pyroxenes (jadeite-omphacite), the eclogites also contain a great quantity of garnets. Destructive analytical methods couldn’t be applied on archaeological specimens with high value, therefore to make the comparison relatively easy between the possible raw materials and the archeological samples we used non-destructive methods during this work. By the chemical composition of HP meta-ophiolites, D’Amico created 9 main groups: jadeitites, Fe-jadeitites, omphacitites, Fe-omphacitites, mixed jade, Fe-mixed jade, Mg-eclogite, intermediate eclogite and Fe-eclogite [3]. This type of classification simplifies the comparison and provides a basis for the further investigations. From the three possible source location the specimens can fit into 7 geochemical groups.
From Monviso south most of the samples are Fe-mixed jades, but jadeities, mixed-jades and an omphacitite can be found among the specimens too. Furthermore this is the only locality where we found Fe-jadeitite. Specimens originated from the alluvium of Po cover wide range of these chemical groups, there are two omphacitites and one sample from nearly every chemical groups. Some of the samples from the Curone sites fit into some of the eclogite chemical groups but most of the specimens cannot fit into any of these, because of the great amount of retromorphous minerals that slightly change the chemical composition of the rocks...
Primary author
Mr
Benjámin Váczi
(ELTE Department of Petrology and Geochemistry)
Co-authors
Dr
Elisabetta Starnini
(School of Humanistic Sciences, Department of Historical Studies, University of Torino, Italy)
Dr
György Szakmány
(ELTE, Department of Petrology and Geochemistry)
Dr
Zsolt Kasztovszky
(MTA Centre for Energy Research)
