PMC4749291_01
Strontium Isotope Ratios of All Imperial Period Individuals.
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T39, and ET76:fall into the categories above. T8 and ET76 have higher-than-expected strontium isotope ratios, showing up as outliers in the box plot in Fig 3. They may have arrived at Rome from a region of older geology such as northern
Histogram of Oxygen Isotope Ratios from Imperial Rome and from Portus Romae.. Portus Romae data are from.
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T39, while not statistical outliers in the oxygen isotope box plot in Fig 5, are nevertheless 0.6-0.7% higher than the next closest local, suggesting they may also be immigrants. They could have arrived at Rome from a drier climate like North Africa. These four individuals highlight the challenge of identifying immigrants to Rome from a vast geographical expanse.
Enamel and Bone delta13Cap Measurements.. Bold, underlined sample IDs indicate individuals identified as immigrants to Rome. Dashed line represents the 2 stdev range of bone isotope ratios for each archaeological population.
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Fig 8 displays these data for the 43 individuals who were subjected to analyses for 87Sr/86Sr, delta18O, and delta13Cap of bone and enamel.