Strontium Varied Across the City: ⁸⁷ Sr/ ⁸⁶ Sr Values at Ur (Tell al-Muqayyar, Iraq)

Analyses of isotope ratios provide researchers with evidence of past and present environments, ecologies, diets and more. For isotope analyses to be maximally effective, however, multiple forms of baseline knowledge need to be gathered. This paper contributes to filling key gaps in our baseline knowledge of strontium (87Sr/86Sr) isotope systematics in southern Iraq by conducting strontium isotope analysis on sediment samples collected across an ancient city, Tell al-Muqayyar (تل ٱلْمُقَيَّر), ancient Ur, from different depths. We (1) establish the scale of the gap between geologic (whole-rock) and bioavailable sediment strontium isotope values on the southern Mesopotamian floodplain and (2) characterise the extent of 87Sr/86Sr isotope spatial and diachronic variability within ancient Ur in order to improve archaeologists’ ability to interpret isotope values collected from southern Mesopotamian archaeological materials.