Naima. Gutknecht (HE-Arc CR, Neuchâtel, Neuchâtel, Switzerland) & Rémy. Léopold (HE-Arc CR, Neuchâtel, Neuchâtel, Switzerland) & Domon Beuret. Emmanuelle (Laténium, Neuchâtel, Neuchâtel, Switzerland)
Pin with decorated head and round section. It has brown-yellow green and corrosion products (Figs. 1-4). Dimensions: L = 6.2cm; WT = 2.6g.
Hauterive - Champréveyres, Neuchâtel, Neuchâtel, Switzerland
Excavation 1983-1985, object from layer 1
Late Bronze Age
Laténium, Neuchâtel, Neuchâtel
Laténium, Neuchâtel, Neuchâtel
The object has been kept in wooden storage, no intervention documented.
The object was analyzed in 1987 by Schweizer. Documentation of the strata in binocular mode of the object was performed in 2022.
The schematic representation below gives an overview of the corrosion structure encountered on the pin from a first visual macroscopic observation.
|Strata||Type of stratum||Principal characteristics|
|CP1||Corrosion product||Light green, thin, discontinuous, non compact, very soft|
|CP2||Corrosion product||Brown, thin, discontinuous, compact, hard|
|CP3||Corrosion product||Black, thin, discontinuous, compact, hard|
|M1||Metal||Yellow, thick, metallic, soft|
Table 1: Description of the principal characteristics of the strata as observed under binocular and described according to Bertholon's method.
No sample has been taken. The observation and analysis were performed directly on the object.
XRF with handheld portable X-ray fluorescence spectrometer (NITON XL5). General Metal mode, acquisition time 60s (filters: Li20/Lo20/M20).
XRF analysis of the pin was carried out on three representative areas of the surface (Fig. 5). Points 1 and 3 were done on yellow areas which seem to be close to the remaining metal, while point 2 was performed on the brown corrosion layer (CP2) where all strata (soil, corrosion products, and metal) are analyzed at the same time.
Table 2 shows that the metal is presumably a tin bronze alloy with possibly some lead. The other elements detected are: Si, S, Fe and P.
|Elements (mass %)||Cu||Sn||Si||S||Pb
|%||+/- 2σ||%||+/- 2σ||%||+/- 2σ||%||+/- 2σ||%||+/- 2σ
Table 2: Chemical composition of the surface of the pin at three representative areas shown in Fig. 5. Method of analysis: XRF.
In the article "Bronze objects from Lake sites: from patina to bibliography" (Schweizer 1994), the corrosion products of the pin 17773 (LAB MAH 85-27) were studied through XRD. The results show that the pin contains copper carbonate (malachite) and copper sulfate (posnjakite), both of these minerals are green.
The corrosion structure has only been documented in binocular mode (Fig. 7).
The pin is made from a tin bronze, possibly containing some lead and is covered with brown and green corrosion products. The corrosion products identified by Schweizer seem to indicate that they developed in terrestrial environment.
References on object and sample
Object files in MiCorr
1. MiCorr_Pin or needle fragment HR-3031
2. MiCorr_Tang fragment of a knife HR-6567
3. MiCorr_Tang fragment of a knife HR-6246
4. MiCorr_Pin HR-18152
5. MiCorr_Pin HR-3071
6. MiCorr_PIN HR-18603
7. MiCorr_Pin HR-3389
8. Rychner-Faraggi A-M. (1993) Hauterive – Champréveyres 9. Métal et parure au Bronze final. Archéologie neuchâteloise, 17 (Neuchâtel).
9. Hochuli, S. et al. (1988) SPM III Bronzezeit , Verlag Schweizerische Gesellschaft für Ur- und Frühgschichte Basel, 76-77, 379.
10. Empa Report 137 695/1991, P.O. Boll.
11. Rapport d'examen, Lab. Musées d'Art et d'Histoire, Geneva GE, 87-194 à 87-197.
12. Schweizer, F. (1994) Bronze objects from Lake sites: from patina to bibliography. In: Ancient and historic metals, conservation and scientific research (eds. Scott, D.A., Podany, J. and Considine B.B.), The Getty Conservation Institute, 33-50.
References on analytic methods and interpretation
13. Robbiola, L., Blengino, J-M., Fiaud, C. (1998) Morphology and mechanisms of formation of natural patinas on archaeological Cu-Sn alloys, Corrosion Science, 40, 12, 2083-2111.