Temperature, δ¹⁸O, δ¹³C, K, Rb, and Sr concentrations and 87Sr/86Sr values of calcites from DSDP Site 92-597 and fish teeth from DSDP Sites 15-149, 68-502, and 98-576 and from sediment cores AMPH-116 and DODO-111

Paleogene bottom waters are thought to have been warmer than those of present day, and hence the calibration of Epstein et al. (1953) yields more reasonable temperatures for late Oligocene/early Miocene bottom waters. K and Rb concentrations are very low, which is consistent with their incompatible character. Sr/Ca ratios of calcites from sub-basement depths less than 35 m are typical for calcites precipitated from pure seawater, whereas the lowermost sample, from a sub-basement depth of 78 m, appears to contain substantial amounts of basaltic Ca. The 87Sr/86Sr ratios of seawater calcites range from 0.708192 to 0.708349, suggesting that they precipitated from 20 to 28 Ma seawater, or within 8 m.y. after formation of the oceanic crust at Site 597.

Our data for calcites from Site 597, drilled on fast-spreading oceanic crust, are similar to data for carbonates from slowspreading crust, except that the high d18O values of the former suggest low temperatures of formation. The low temperatures of calcite formation apparently indicate that the oceanic crust at Site 597 was unusually permeable, allowing rapid circulation of seawater.