Question

You are an archaeologist excavating an Archaic period (c. 3000 BCE) site on the Pacific coast of Oaxaca, Mexico. At the site are the remains of household structures that were destroyed in a large fire, with a number of cooking and serving vessels apparently abandoned in place where they were last used, and a cemetery with a number of adult skeletons close to the houses. You want to learn more about the diet and social organization in the community. Houses on the west side of the site have lots of animal bone refuse in them (primarily deer), while houses on the eastern side have considerable quantities of large fish bones. The cemetery is similarly divided into a western portion and an eastern portion, and you hypothesize that the individuals buried on the west may have lived in the western houses, and the same for the east (this is termed a moiety social structure by anthropologists). You also find evidence for wooden braziers with cannabis residue in the eastern cemetery, but not in the western cemetery or any of the houses.

What element could you test from the burials to determine whether the western burials come from the western houses?

Answer 1

By analysing the human skeletal remains we can establish the dietary habits of an adult human being. The ratios of C13 isotope of carbon and N15 isotope of nitrogen in bone collagen indicates the major protein sources in the diet during his life time.

The C13 isotope ratio of a person with predominant marine diet will be around -13 % and that for a person with terrestrial diet will be nearly -20%. Houses on the western side had lots of animal bone refuses in them, showing that they had a predominantly terrestrial diet. On analysing the C13 isotope ratio in the bone collagen from the western side cemetry, if the value is around -20%, then the remains belong to the western houses.