Sr Isotope Analysis of Human Remains from Settlement Pits at Stillfried/March. Reappraising Diagenetic Changes

Objectives: Since the late 1970s, when the first human skeletal remains from a pit (V1141) located within the Late Bronze Age hillfort at Stillfried an der March, Austria, were discovered, their deviation from the predominant burial rite of cremation became the subject-matter of a variety of archaeological and bioanthropological studies. Through continuous archaeological excavations, further settlement pits with unusual human inhumation burials or depositions of isolated skeletal remains became apparent and posed the question of their possible non-local origin. The human samples in this study come from the Pits V841 and V1133, furthermore we re-investigate two individuals from V1141. The aim is to get a better understanding of Stillfried's population structure and to enrich the debate about the mortuary practices of the Urnfield culture. Material and Methods: Here we present and discuss the radiogenic Sr isotope ratios determined in the enamel of eleven individuals from three settlement pits: Eight individuals from Pit V841 and one individual, represented by a skull without mandible (calvarium) of a 12-13-year-old child from Pit V1133; two individuals were taken from Pit V1141 and re-investigated for comparative reasons. We compared all data to signals of the local environment derived from modern environmental samples and to the autochthonous signal of the Late Bronze Age derived from archaeological faunal remains (incl. mussels) and archaeological plants. Further, we investigated and discussed the potential of a mathematical approach to access biogenic Sr isotopic information from diagenetically altered dentine. Results: It has been shown that both supposedly autochthonous and allochthonous (non-local) individuals are buried within the settlement pits of Stillfried, which shows that burial practices do not relate to the individual's origins. In particular, the n(87Sr)/n(86Sr) isotopic values of six individuals match the supposedly autochthonous Sr signature, while the other five individuals represent allochthonous individuals. Three of the latter showed n(87Sr)/n(86Sr) values that were higher and two that were lower compared to the autochthonous Sr range, thereby indicating at least two different homelands. Despite the small sample size which constrains the validity of the data, the diversity of the inhabitants' provenance reflects a high mobility. This may support the interpretation of Stillfried as a 'central site'- A finding which is also important in the wider context of the European Late Bronze Age.