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Theses and Dissertations

Name:Theresa Jane Gilbertson
Degree:Ph.D.
Professor:Robert H. Tykot
Year:2015
Title:A Comparative Analysis of Portable X-ray Fluorescence Spectrometry and Stable Isotopes in Assessing Ancient Coastal Peruvian Diets
  
Abstract:

This dissertation explores a cross-cultural analysis of the dietary signatures of four coastal cultures of prehistoric Peru. A combination of elemental analysis based on portable x-ray fluorescence spectrometry (pXRF), testing trace elements presented in 209 individuals’ skulls representing the Nazca (38), Cañete (33), Lima (40), and Moche (98) valleys and/or cultures of the first millennium AD, is weighed in conjunction with isotope ratio mass spectrometry (IRMS) to analyze human bone collagen and bone apatite derived from a portion of the individuals represented in the Nazca, Cañete, and Lima cranial samples.
Evidence from the results of both tests are weighed using descriptive statistics supported with bivariate correlations and linear regression to determine that the pXRF data on the trace elements strontium (Sr), barium (Ba), and iron (Fe) from the Moche collection do present potential for accurately portraying diet of those individuals represented in this sample. Additional hypotheses tested include potential for preferential diets based on sex, age, and status as well as attempting to place the valley of Cañete in the cultural sphere of either Lima or Nasca during the Early Intermediate Period. While there was no significant statistical difference in diet based on age in any of the individual valley datasets, there was one valley, Nazca, which showed a considerable variation in diet based on sex. From data derived from this particular sample set, there are mixed results in attempting to apply status to a diet of preferential high nitrogen sources such as marine mammals and large fish. In attempting to place Cañete in the cultural sphere ofeither Lima or Nasca, it was determined that cultural remains appear to be linked predominately to artifacts and practices of the Lima Culture, but the dietary difference in both stable isotope and trace elements signatures combined with the samples which instead aligned more closely with the Nasca Culture suggests that perhaps Cañete was a marginal space which allowed for the settlement and interaction of peoples from both neighboring cultures without prejudice. Overall, results indicate it would be premature to suggest pXRF replace destructive analysis in determination of diet. Due to the small sample size of stable isotopes deemed viable in testing, it is suggested that a larger sample of stable isotopes should be considered in similar testing and that the major elements from pXRF should also be used before a suggestion that destructive analysis was no longer warranted in many cases for deducing diet in ancient populations.