SYNCHROTRON FTIR MICRO‐SPECTROSCOPY APPLIED TO THE STUDY OF POLISHED SERPENTINITE ARTEFACTS: A NON‐DESTRUCTIVE ANALYTICAL APPROACH

In prehistory, serpentinite was one of the most frequently used raw materials to produce polished stone artefacts. Several conventional analytical techniques can be applied to identify the serpentine minerals, but their application generally requires a powdered sample. This implies that the artefacts to be analysed must be damaged, and the possibility of analysing a mixture of different serpentine polytypes is high. The use of spatially resolved techniques is therefore a necessity to overcome this problem. Several thin sections of serpentinitic rocks and prehistoric axes have been analysed by synchrotron radiation Fourier transform infrared micro‐spectroscopy. The spectra were acquired directly on specific points of polished stone artefacts and this allowed the recognition of the different polytypes of serpentine minerals without causing any damage to the objects. The results show the infrared micro‐spectroscopy technique to be a useful tool for the characterization of archaeological lithic material.     

COPPER AND BRONZE DURING THE ENEOLITHIC AND EARLY BRONZE AGE: A METALLOGRAPHIC EXAMINATION OF AXES FROM THE NORTHALPINE REGION*

This paper presents the results of a metallographic examination of Eneolithic and Early Bronze Age axes from the Northalpine region of central Europe. During this period, different types of copper were in use: arsenical copper, Fahlerz copper and tin bronze. We examine if and to what extent the different properties of the metals used were known to prehistoric metalworkers and actively manipulated in the production of the axes. The development of methods of casting and smithing is discussed. Both aspects contribute to our understanding of the nature of prehistoric technological change. During the Early Bronze Age of the Northalpine region, different traditions of early metallurgy can be identified, which differ in their use of Fahlerz copper, their attitude towards tin alloying and the use made of tin bronze in the production of the axes. These traditions can only be adequately described by reference to both composition—that is, access to different types of copper as well as tin—and knowledge of the production techniques provided by metallographic data.     

SHAFT‐HOLE AXES FROM CAPUT ADRIAE: MINERALOGICAL AND CHEMICAL CONSTRAINTS ABOUT THE PROVENANCE OF SERPENTINITIC ARTEFACTS*

The change of raw materials used to produce stone axes during the Neolithic to Copper Age transition in northeastern Italy, central and western Slovenia and northwestern Croatia (Caput Adriae) has been recently linked to the development of early European metallurgy. Serpentinite shaft‐hole axes occur commonly in the archaeological context of this region and their rounded irregular shape suggests that the raw material was mainly sourced from secondary deposits. The aim of the present study is to characterize with multiple analytical methods, including synchrotron radiation, the axes and locate the primary outcrop(s) of raw materials and related secondary exploitation areas. All the analysed artefacts are manufactured from peridotites and probably pyroxenites completely metamorphosed in greenschist facies and characterized by antigorite, diopside and magnetite, sometimes rimmed by penninite. Mineralogical and petrographic data exclude most Eastern Alps outcrops as possible raw material sources, thus limiting the research to the Hohe Tauern. Chemical data reveal a close homogeneity for the peridotite‐derived axes and therefore demonstrate a selection of the most suitable raw material for axe production. Provenance from Hohe Tauern and related secondary deposits of the Drava River hydrographical system agrees with previous studies, as this region is rich in copper ore deposits, which have been exploited since prehistory.     

NEOLITHIC ‘GREENSTONE’ AXE BLADES FROM NORTHWESTERN ITALY ACROSS EUROPE: A FIRST PETROGRAPHIC COMPARISON*

Neolithic polished stone axe blades, manufactured with uncommon lithologies such as Alpine eclogites, jades and other HP metaophiolites, were exploited from primary and secondary occurrences in Piemonte and Liguria and dominate the north Italian and south‐east French polished stone blades used as functional tools (for deforestation and woodworking). In other European countries the same lithologies are found less frequently or only occasionally as axe blades; in north‐west Europe they were frequently used for manufacturing ceremonial axes that have shapes that are not present in the Italian Neolithic tradition. This paper undertakes a preliminary examination of the case, prevalently from a petrographic point of view, comparing the well‐established Italian petroarchaeometric knowledge with the rather poorer petrographic basis of the European eclogite/jade axes. A provisional picture of the distribution of these axes in Europe is provided and some interim interpretations and open problems are discussed.     

SHAFT‐HOLE AXES FROM CAPUT ADRIAE MADE FROM AMPHIBOLE‐RICH METABASITES: EVIDENCE OF CONNECTIONS BETWEEN NORTHEASTERN ITALY AND CENTRAL EUROPE DURING THE FIFTH MILLENNIUM BC

Here we show the results of a study concerning a small group of shaft‐hole axes found in northeastern Italy, made from amphibole‐rich metabasites, fine‐grained and free of phenoblasts. The main mineral phases are amphibole, ranging from actinolite to hornblende, and plagioclase (An_10–15 and An_70–77). The amphiboles generally show a needle shape and are often radially arranged. Quartz is present in thin veinlets, while ilmenite is widespread in small patches. The petrographic and geochemical features suggest that the axes originate from the southern thermal aureole of Tanvald granite in northern Bohemia. In accordance with this provenance, the typology of the tools shows similarities with the perforated shoe‐last axes spread across Central Europe during the fifth millennium bc and made from similar raw material. For the first time, these axes give evidence of long‐distance (about 800 km) contacts between northeastern Italy and Central Europe during the Neolithic.     

SHAFT‐HOLE AXES FROM SLOVENIA AND NORTH‐WESTERN CROATIA: A FIRST ARCHAEOMETRIC STUDY ON ARTEFACTS MANUFACTURED FROM META‐DOLERITES*

A group of Copper Age shaft‐hole axes from Caput Adriae (northeastern Italy, western Slovenia and northwestern Croatia) manufactured using meta‐dolerite have been analysed for major and trace elements. All the samples show magmatic textures and well recognizable relicts of primary mineralogical phases. Petrographic observations suggest an ophiolitic provenance of the protolithic source(s) while geochemical data indicate that the original magmas originated in a fore arc or pre arc tectonic setting. Strong similarity has been found with several lithotypes from the Banija Ophiolite Complex (Croatia), here indicated as the most probable source area. Considering the available archaeometric data about shaft‐hole axes found in northern Italy and Caput Adriae in comparison to those of axe blades discovered in the same area, it emerges that there is a utilization of different rock types, the source of which appears to be quite close to the discovery sites. In the investigated area the shaft‐hole axes are largely made from ophiolitic‐related rocks which are associated with copper deposits. Consequently there may have been a relation between the localization of the geological sources of shaft‐hole axes and the development of metallurgical activities.