Pore-water strontium concentrations generally increase with depth and distance from the Blake-Bahama Platform edge. The measured strontium isotopic values of pore waters are commonly independent of host sediment age and burial depth. This indicates that the pore waters have exchanged strontium with one or more sources of different age. A comparison of measured and predicted strontium isotopic compositions indicates that the assumption that biostratigraphic ages are an accurate predictor of sedimentary carbonate strontium isotopic composition and is valid for these sediments, and that clay mineral diagenesis has not introduced exotic strontium to the pore water.
Strontium isotope and concentration profiles indicate complicated patterns of strontium redistribution. The data are not dense enough to define the overall circulation patterns uniquely. However, data from all the sites indicate that strontium from modern seawater has invaded the upper 100-300 mbsf enough to significantly alter the profile shapes. The greatest amount of seawater invasion is seen at Site 1049, which is directly at the platform edge. The reversal in the strontium concentration profile and the isotopic values at Site 1051 indicate that strontium has migrated downward (or at least laterally) from intermediate levels. At Site 1052, the site furthest from the escarpment, Mesozoic strontium appears to have moved upward into the Tertiary strata.