Application of Trace Element and Sr Isotope Analyses to Anthropological and Groundwater Research


Antonio Simonetti

Associate Professor, Department of Civil and Environmental Engineering and Earth Sciences,
University of Notre Dame


Historically, Sr isotope analysis of biological and geological samples have been conducted by TIMS
(thermal ionization mass spectrometry); although, the latter technique produces extremely accurate
and precise data, it is in fact a labor-intensive and time-consuming technique. Sr isotopic
measurement by solution mode MC-ICP-MS greatly increases sample volume throughput with little (if
any) detriment to the quality of individual analyses (compared to TIMS). Recent studies have also
reported reliable Sr isotope measurements and elemental concentrations within geologic and biologic
samples at high spatial resolution using various LA-(MC)-ICP-MS instrument configurations. The
relatively rapid nature of an individual laser ablation Sr isotope analysis (i.e. minutes) could
possibly revolutionize (if successful) the manner in which migration studies of ancient
civilizations are conducted.


Sr isotope analysis of human tissue has proven to be an important tool for examining ancient human
migration patterns. The development and activities of ancient polities are the subjects of much
anthropological inquiry. Exploring population dynamics during significant sociopolitical changes
allows for a more thorough understanding of those involved in the power relationships of these
ancient interactions. In areas where the geological variability is sufficient, strontium isotope
(^87Sr/^86Sr) analysis has proven to be a successful technique to address questions of
archaeological significance regarding the interactions of societies such as Roman period mobility
in Britain and Europe and the movements of the Wari, Inca, and Tiwanaku in South in addition to
numerous other past cultures. Dental enamel from faunal remains is used to examine variability in
strontium sources in seven regional sites; human enamel samples are analyzed from eight Nile Valley
sites in order to trace human movements. The faunal samples show a wide range of ^87Sr/^86Sr values
demonstrating that some animals were raised in a variety of locales. The results of the human
samples reveal overlap in ^87Sr/^86Sr values between Egyptian and Nubian sites; however, Egyptian
^87Sr/^86Sr values (mean/median [0.70777 ±0.00027]) are statistically higher than the Nubian
^87Sr/^86Sr values (mean [0 .70762], median [0.70757 ±0.00036], suggesting that it is possible to
identify if immigrant Egyptians were present at Nubian sites. Samples examined from the site of
Tombos provide important information regarding the sociopolitical activities during the New Kingdom
and Napatan periods. Based on a newly established local ^87Sr/^86Sr range, human values, and
bioarchaeological evidence, this study confirms the preliminary idea that immigrants, likely from
Egypt, were present during the Egyptian New Kingdom occupation of Nubia.


The second case study involves reporting high precision Sr isotope determinations and trace element
analyses for water samples retrieved from the coastal region of Benin in order to help delineate
the interaction between groundwater and surface water. Understanding the incursion of saltwater
within the Godomey Well Field is critical since the Well Field supplies drinking water for the city
of Cotonou.