Strontium isotopic composition of Pliocene and Pleistocene molluscs from emerged marine deposits, North American Arctic
High-precision strontium (Sr) isotopic measurements were obtained for 53 Pliocene and Pleistocene molluscan shells from emerged marine deposits around the coasts of Arctic North America to test whether such data can be used for chronostratigraphic purposes. 87Sr/86Sr ratios from Sr isotopic measurements on many marine fossils from Arctic Ocean borderland sites are broadly consistent with their expected values based on independent age control and on a comparison with the Sr isotopic evolution of seawater recorded in deep-sea cores. All 87Sr/86Sr ratios measured for shells from Middle and Late Pleistocene deposits are consistent with expected values, but only 9 of 22 ratios in shells from older deposits are consistent with independent age estimates. Aberrant 87Sr/86Sr ratios are consistently higher than expected. At Nome, Alaska, and Baffin Island, Canada, all 87Sr/86Sr ratios are higher than expected. Because these shells were formed along the Pacific Ocean and Atlantic Ocean margins, respectively, their h...