Exploring the Origins and Mobility of the Medieval Monastic Inhabitants of a Cave Church in Gurat, France using Strontium Isotope Analysis

Abstract

Researchers inevitably must destroy a portion of their sample to conduct stable isotope analyses and obtain the chemical signatures embedded within biological hard tissues such as tooth or bone. However, the degree to which a sample is destroyed depends upon the chosen analytical technique. In order to conduct strontium (Sr) isotope analysis on dental and skeletal tissues acquired from Gurat, France the research presented here employs laser ablation multi- collector inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS). The comparison of 87Sr/86Sr values allows researchers to explore past individual and/or population mobility. Within Gurat, a small village located in the region of Poitou-Charentes in southwestern France, is a hand-carved limestone cave church that is one of several mid-sized structures that likely developed from a hermitic site to a centre for monasticism by the High Middle Ages. Gurat is unique in that abundant archaeological data and a collection of unstudied human remains are available for analysis after remaining in storage for fifty years. This research therefore represents the first effort to understand who the people at Gurat were and what the meaning of the site may have been locally and regionally. Overall, the study showed that many of the Gurat individuals were in fact migrants to the village. In turn, this reflects and reinforces the regional importance of this medieval monastic centre. This research also highlights the ability of laser ablation to minimize destruction of irreplaceable bioarchaeological material.