An assessment of procedures to remove exogenous Sr before 87Sr/86Sr analysis of wet archaeological wool textiles

Bronze Age wool: provenance and dye investigations of Danish textiles

“…The strontium isotope analyses of the textile samples (comprising both local and non-local wool) from these two burials yield similar datasets, with ratios representing a relatively narrow range of values ( 87 Sr/ 86 Sr∼0.710-0.712). The only exception is the weft from the Borum Eshøj A wrap-around garment, which has a higher strontium isotope value of 87 strontium isotopic values contrast with the much broader range yielded by the Nybøl samples ( 87 Sr/ 86 Sr∼0.715-0.725), and demonstrates that these textiles were made entirely of non-local wool. Hence, the wool origin for the Nybøl textile collection seems to differ from that of the Trindhøj and Borum Eshøj A textiles, which is in agreement with previous studies (Bergerbrant et al 2013).…”

“…Bronze Age wool: provenance and dye investigations of Danish textiles The strontium isotope results (Table 1) show a large overall variation of values, ranging from relatively low strontium isotope ratios of 87 Sr/ 86 Sr = 0.70867 (±0.00004) to high strontium isotope ratios of 87 Sr/ 86 Sr = 0.7279 (±0.00001) ( Figure 6). Previous studies delineating the range of bioavailable strontium isotope compositions characteristic for Denmark (excluding the island of Bornholm in the Baltic Sea, and hereafter referred to as Denmark), have resulted in a baseline range defined by 87 Sr/ 86 Sr values of 0.708-0.711 , 2013Frei & Price 2012). Consequently, the results of this study suggest that 70 per cent of the wool fibres analysed came from sheep that grazed outside the geographic limits of present-day Denmark.…”

Transhumance pastoralism of Roccapelago (Modena, Italy) early‐modern individuals: Inferences from Sr isotopes of hair strands

“…However, one of the main problems with hair is contamination by Sr from external sources. These include both pre‐burial (e.g., environmental exposure and cosmetic treatments; Chau et al, ) and post‐burial sources (e.g., diagenetic contamination; Von Holstein, Font, Peacock, Collins, & Davies, ). To date, it is not possible to discriminate the endogenous from the exogenous Sr, and measured 87 Sr/ 86 Sr ratios result from a mix of both.…”

“…Since metal ions are positively charged, they have a high affinity for negatively charged melanin polymers (Frei et al, ; Morton, Carolan, & Gardiner, ). In fact, it has been shown that buried wool textile may present exceptionally high Sr concentration for this reason (Von Holstein et al, ). In archaeological and paleontological studies of bones, Rare Earth Elements (REEs) are commonly used as a proxy for elemental uptake during diagenetic processes of human and animal remains, being usually present at very low concentration within the living organism and thus mostly coming from post‐burial uptake (see, e.g., Reynard & Balter, ).…”

Provenancing Archaeological Wool Textiles from Medieval Northern Europe by Light Stable Isotope Analysis (δ13C, δ15N, δ2H)

“…Light stable isotopic analysis of archaeological keratinous tissues has so far been carried out only on material which is unusually well-preserved, for example under conditions of permafrost or desiccation [ 59 , 60 ]. In contrast, hair from anoxic waterlogged deposits, from which a high proportion of medieval European textiles derive, is clearly altered by diagenesis, either through chemical mechanisms (protein hydrolysis, deamidation, oxidation, breaking of S-S crosslinks) or microbiological activity (fungal and/or bacterial attack) [ 61 – 64 ]. These processes can add elements (O, H) to the fibre, remove elements (N, H) from the fibre, or cause protein chain scission, leading to loss of amino acids (AA).…”