Strontium-isotope stratigraphy in the Late Cretaceous: international correlation of the Campanian/Maastrichtian boundary. Terra Nova

Abstract: Marine 87Sr/86Sr decreases from 0.70775 in the Cenomanian to0.70730 in the middle Turonian before increasing in a near-linear manner to>0.70775 in the early Maastrichtian. This variation has been defined using samples from the English Chalk that are closely integrated with the macrofossil and microfossil biostratigraphy of northwestern Europe. With this new isotope curve a stratigraphic resolution isattainable incorrelation that is typically _+0.8 Ma for the Santonian and Campanian stages. Isotopic and biostrati-graphic orrelations between Dorset and Norfolk, in the UK, agree within the limit of analytical error in S:Sr/S6Sr. Strontium isotope stratigraphy is used increas-ingly for correlation and dating of marine car-bonates, evaporites and phosphates (Wickma