The earliest lead ore processing in Europe. 5th millennium BC finds from Pietrele on the Lower Danube.

Svend Hansen,Meda Toderaş,Daniel Steiniger,Ignacio Montero-Ruiz,Salvador Rovira,Peter F Biehl

doi:10.1371/journal.pone.0214218

Abstract

Eleven biconical vessels from the Copper Age sites Pietrele and Blejeşti (Romania) have been investigated using p-XRF. In most cases, traces of lead could be measured on their surfaces. Samples of slag-like material from two vessels and the clay of one vessel were investigated using laboratory methods, namely SEM, XRD, LIA and optical microscopy. The vessels were obviously used as a kind of crucible in which slag-like remains and galena ore were detected. It still remains unclear as to what final product was gained by smelting galena in this way. The amount of these such vessels in the Pietrele settlement, their appearance as grave goods in Pietrele and Vărăști (Romania), and their supposed occurrence in a number of other Copper Age settlements in Romania and Bulgaria show the significance of this phenomenon. It must have been a widespread and more or less well known practice, an important part of cultural habit during a particular period in the Lower Danube region and likely even farther afield. For the first time, extensive experimentation with lead ore can be shown in a clear chronological horizon, ca. 4400–4300 BCE in southeastern Europe.

Highlights

Introduction and archaeological contextMetallurgy is one of the basic innovations that changed the lives of prehistoric societies and still plays a decisive role in modern societies; it is worth highlighting here the enormous importance of the Rare Earth Elements for industrial purposes.According to the present state of research, copper mining, processing and casting started at the turn of the 6th to the 5th millennium BCE [1]
It is true that the probable lack of control over the chemistry of the process with such a precarious technology as that proposed by the Blejeşti and Pietrele vessels could lead to materials such as those studied here, which might be masking the reality we barely glimpse
The technology put into practice is undoubtedly very novel and involves a high degree of empirical knowledge of the properties of a particular metal sulphide and the by-products of its decomposition by thermal effect in a controlled atmosphere such as the one provided by an almost closed chamber

Summary

Introduction and archaeological context

Metallurgy is one of the basic innovations that changed the lives of prehistoric societies and still plays a decisive role in modern societies; it is worth highlighting here the enormous importance of the Rare Earth Elements for industrial purposes. Two more crucibles (Figs 9 and 10; P12F7230116 and P12F723CER53.4) probably stem from a neighbouring house that was excavated in 2012 These pieces were discovered in the direct vicinity of an oven. The Copper Age necropolis of Vărăști, belonging to the Gumelniţa culture, should be mentioned here as well: biconical objects were found in ten graves from this site [18] The significance of these finds is obvious; for the first time, metallurgical activities could be detected in a settlement mound. The crucibles from Pietrele and Blejeşti are the first pieces of evidence for the use of lead ore in southeastern Europe, though there could be one earlier case from the Vinča settlement of Donja Tuzla, where grey powder detected in a normal pot was determined to be lead sulphide [29]. This was the path from pure copper objects to copper alloys

Materials and methods

Conclusions from the laboratory analysis

Method

Method SEM

Findings

Conclusions