In lieu of an abstract, here is a brief excerpt of the content:

15 Tracing Human Mobility with 87 Sr/86 Sr at Anse à la Gourde, Guadeloupe Mathijs A. Booden, Raphaël G. A. M. Panhuysen, Menno L. P. Hoogland, Hylke N. de Jong, Gareth R. Davies, and Corinne L. Hofman Introduction The presence of nonlocal pottery, lithic material, shell, and bone at Anse à la Gourde suggests the existence of interaction networks in the Lesser Antilles in which raw materials and exotic items circulated (Hofman et al. 2001; Hoogland and Hofman in press; Knippenberg 2006). In this study we assess the applicability of strontium isotope ratios in teeth to distinguish nonlocal burials from local burials in order to determine the extent of residential mobility of the buried population at the site. Strontium isotope ratios are increasingly successfully used to make a distinction between local and nonlocal burials recovered from archaeological sites (e.g., Bentley et al. 2004; Price et al. 2002; Wright 2005). Generally, this technique is applied in areas with variable strontium ratios. The site of Anse à la Gourde is located in the Lesser Antilles in the eastern part of the island of Guadeloupe (Figure 15.1). The Lesser Antilles island arc, to which Guadeloupe belongs, is theoretically a suitable area for this type of provenance research since large variations in geochemistry occur along the arc (e.g., Macdonald et al. 2000; Van Soest 2000). From Marie-Galante and Guadeloupe northward the Lesser Antilles separate into an outer arc (Limestone Caribbees) and an inner arc (Volcanic Caribbees). As a consequence the soil on different islands is characterized by different geochemical and isotopic compositions. It is expected that this variation will be reflected in the composition of the remains (bone and enamel) of the humans who collected a significant proportion of their food from these soils. Focus will be laid on the analysis of dental enamel samples. Tooth enamel is not altered biologically after it is formed during childhood. The densely packed crystal Tracing Human Mobility with 87 Sr/86 Sr / 215 structure of apatite in tooth enamel protects the biogenic strontium isotope signature from outside diagenetic influences, such as microbial attack and dissolution by groundwater (Budd et al. 2000). Hence, enamel preserves the isotope signature of an individual’s diet during childhood. Bone is constantly remodeled during life and will tend to equilibrate with the dietary strontium consumed in vivo. Moreover , the more porous crystal structure of bone makes it more vulnerable to postmortem diagenetic alteration (Budd et al. 2000). In order to distinguish locals from nonlocals, the local strontium signature was determined and the distribution of strontium isotope ratios in the population were analyzed. The local strontium signature was determined by means of the analysis of enamel of rice rats and soil samples from the burial pits. In addition, a simple statistical procedure as used by Wright was applied to analyze the distribution of human enamel isotope ratios. Wright (2005) suggests that the local population in a data set is best defined as the largest possible subset of samples that is normally distributed, that is, is symmetrical around the mean and contains 95 percent of cases within two standard deviations of the mean. We attempted to determine this subset by iteratively excluding outliers from the data set, defined based Figure 15.1. Map of the Antilles and the position of Anse à la Gourde on Guadeloupe. 216 / Booden et al. on a 95 percent confidence interval, until no further statistical outliers are identified and the skewness of the subset is approximately 0. Geology The island of Guadeloupe consists of two sister islands: the volcanic Basse-Terre to the west and the limestone-dominated island of Grand-Terre to the east. Anse à la Gourde is located on the extreme eastern end of the latter, Pointe Chateaux (Figure 15.1). Maury and colleagues (1990) provide an overview of the geology of Guadeloupe and La Désirade. The surface of Grand-Terre consists entirely of Pliocene and Quaternary limestone (Andreieff and Cottez 1976). A reef platform was uplifted during the Pleistocene, starting in the southwest, and later followed by the northern and eastern parts. Basse-Terre has been the locus of active volcanism for at least 4 million years.Volcanic activity has shifted over time in a southerly direction and is currently concentrated in the Soufrière volcano. Anse à la Gourde is located directly on the shoreline of the northern coast of Pointe Chateaux. It is exposed to continuous northeastern trade winds and strong surf, causing abundant sea spray that will add marine strontium to...

Share