Mobility, landscape, and the functions of the cave. Evidence from strontium isotopes

The strontium isotopic ratio (87Sr/86Sr) measured in the inorganic matter of skeletons is used in archaeology to assess past mobility and residential patterns. The bioavailable strontium in the tissues reflects that of the plants eaten, which in turn replicates that of soil and water as derived bu the geological background of the lived-in environment. The 87Sr content of bedrock is formed by decay of rubidium (87Rb), so that old rocks will have higher 87Sr than younger ones