Variations in the strontium isotope composition of seawater during the Paleocene and early Eocene from ODP Leg 208 (Walvis Ridge)

We refined the strontium isotope seawater curve for the Paleocene and early Eocene by analysis of samples recovered from the Walvis Ridge during Ocean Drilling Project (ODP) Leg 208. The highest Sr-87/Sr-86 values occurred in the earliest Paleocene at similar to 65 Ma and generally decreased throughout the Paleocene, reaching minimum values between 53 and 51 Ma in the early Eocene before beginning to increase again at similar to 50 Ma. A plausible explanation for the Sr-87/Sr-86 decrease between 65 and 51 Ma is increased rates of hydrothermal activity and/or the eruption and weathering of large igneous provinces ( e. g., Deccan Traps and North Atlantic). Strontium isotope variations closely parallel sea level and benthic delta O-18 changes during the late Paleocene and early Eocene, supporting previous studies linking tectonic reorganization and increased volcanism to high sea level, high CO2, and warm global temperatures.