Pin HR-17773 - Tin Bronze - Late Bronze Age - Switzerland

Pin HR-17773 - Tin Bronze - Late Bronze Age - Switzerland

Pin HR-17773

Naima. Gutknecht (HE-Arc CR, Neuchâtel, Neuchâtel, Switzerland) & Rémy. Léopold (HE-Arc CR, Neuchâtel, Neuchâtel, Switzerland) & Domon Beuret. Emmanuelle (Laténium, Neuchâtel, Neuchâtel, Switzerland)

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Credit Laténium, C.Cevey.

Fig. 1: Pin with decorated head and round section,

Credit HE-Arc CR, L.Rémy.

Fig. 2: Brown-yellow corrosion products (detail) around the head of the pin,

Credit HE-Arc CR, L.Rémy.

Fig. 3: Brown-yellow corrosion products (detail) on the middle part of the pin,

Credit HE-Arc CR, L.Rémy.

Fig. 4: Brown-yellow and green corrosion products (detail) in an area close to the tip of the pin,

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.

Jewellery

Hauterive - Champréveyres, Neuchâtel, Neuchâtel, Switzerland

Excavation 1983-1985, object from layer 1

Late Bronze Age

Hallstatt A2/B

Lake

Laténium, Neuchâtel, Neuchâtel

Laténium, Neuchâtel, Neuchâtel

HR-17773

The object has been kept in wooden storage, no intervention documented.

Complementary information

The object was analyzed in 1987 by Schweizer. Documentation of the strata in binocular mode of the object was performed in 2022.

Credit HE-Arc CR, L.Rémy.

Fig. 5: Sides A and B (opposite sides) of the pin showing the XRF analysis areas (red circles),

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.

Credit HE-Arc CR, N.Gutknecht.

Fig. 6: Stratigraphic representation of the corrosion structure of the pin by macroscopic and binocular observation using the Micorr application with reference to Fig. 7,

Fig. 7: Stratigraphic representation of the corrosion structure of the pin observed macroscopically under binocular microscope using the MiCorr application with reference to the whole Fig. 6. The characteristics of the strata, such as the discontinuity, are accessible by clicking on the drawing that redirects you to the search tool by stratigraphy representation, Credit HE-Arc CR, N.Gutknecht.

No sample has been taken. The observation and analysis were performed directly on the object.

Tin Bronze

None

85-27

None

None

Complementary information

None.

Analyses performed:

Non-invasive approach

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
 Fe
 P
  
  % +/- 2σ  % +/- 2σ % +/- 2σ % +/- 2σ % +/- 2σ
 %
 +/- 2σ
 %
 +/- 2σ
 Total 
1 82.0 0.1 14.0 0.06 1.5 0.07 0.6 0.02 0.5 0.02 0.4 0.02 0.3 0.03 99.3
2 81.0 0.1 14.0 0.05 0.6 0.06 1.5 0.03 0.5 0.02 1.5 0.02 0.3 0.02 99.4
3 81.5 0.14 14.1 0.06 1.6 0.08 0.7 0.03 0.6 0.02 0.5 0.02 0.7 0.04 99.7

Table 2: Chemical composition of the surface of the pin at three representative areas shown in Fig. 5. Method of analysis: XRF.

None.

None

Cu

Sn

Complementary information

None.

None.

None

None

Complementary information

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

References object
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.

References sample
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.