Among their topics are the stratigraphic and pottery sequence of Trench B1: a first approach to investigating ceramic and chronological associations, the chipped stone industries: a general presentation, Neolithic bone and antler artefacts, radiogenic strontium
isotopes from the burials, wood charcoal analysis from sediments, and speleothems from Alepotrypa Cave: towards climate reconstruction.
While textile evidence has been used to argue for an ethnic enclave of Tiwanaku colonists within the Coyo Oriental cemetery (Kolata 1993:277; Oakland Rodman 1992), radiogenic strontium isotope analyses of human remains from Coyo Oriental suggests that first generation immigrants to the oases were rare (Knudson 2008), and it is possible that stylistically different textile groups may instead represent local lineages with differential access to Tiwanaku-style trade goods (Goldstein 2005:94).
Together, the use of radiogenic strontium isotope ratios ([sup.87]Sr/[sup.86]Sr) and stable oxygen isotopic values ([delta][sup.18]O) allows the identification of individuals who spent their childhood in a region geologically or meteorologically different from San Pedro de Atacama (see Bentley 2006 and Gat 1996 for reviews).
Radiogenic strontium and stable oxygen isotope analysis
The distribution of radiogenic strontium and stable oxygen isotope values found in the tooth enamel of individuals from the Solcor ayllu is presented in Figure 5.
Differences in radiogenic strontium isotope signatures within the San Pedro population do appear to pattern with cemetery membership.
If the slightly divergent radiogenic strontium isotope discrepancies between individuals interred in the Solcor 3 and Solcor Plaza cemeteries represent differences in the geographic origin of food sources, they may indicate that dietary distinctions between the social groups were maintained based not only on the types of foods consumed but also on the origins of food sources exploited.
Such a high [sup.87]Sr/[sup.86]Sr ratio is indicative of a radiogenic strontium flux and the shale's [sup.87]Sr/ [sup.86]Sr ratio was derived from tectonoclimatic processes such as the exposure and chemical weathering of ancient crystalline rocks with high [sup.87]Sr/[sup.86]Sr ratio .
The radiogenic strontium, which is responsible for the high [sup.87]Sr/[sup.86]Sr ratio of oil shale samples, was probably derived from the Nadi Kangri volcanic-volcaniclastic rocks.