HIGH-RESOLUTION SR-87 SR-86 CHEMOSTRATIGRAPHY OF THE SILURIAN - IMPLICATIONS FOR EVENT CORRELATION AND STRONTIUM FLUX/

Analyses of Sr-87/Sr-86 in Silurian conodonts recovered from localitie s in North America and Europe representing 13 of the 14 defined Siluri an conodont zones provide a high-resolution record of seawater chemist ry for the Silurian Period. These data, which are characterized by lit tle or no scatter, depict several high-frequency cycles superimposed o n a gradual longer term rise in Sr-87/Sr-86 for the Silurian. High-fre quency cycles have a duration of about one conodont zone, and many cor relate with sequence boundaries recognized around the world. These dat a provide a much higher resolution image of secular changes in Sr-87/S r-86 during the Silurian and may require a rethinking of models of str ontium isotope flux in marine basins.