Fission track dating of apatite and sphene from Paleogene sediments of Deep Sea Drilling Project Leg 81, Site 555.

Abstract

Fission track ages of individual crystals of detrital apatite and sphene separated from early Eocene and Paleocene sandstones at Site 555 indicate the contribution of detritus from source rocks of at least three distinct age groups. A major group of Tertiary (56+ or -3 Ma) apatite ages is compatible with either contemporaneous or near contemporaneous volcanism or rapid unroofing of high level intrusives like those identified previously on Rockall Island and Greenland. Cretaceous (100+ or -20 Ma) apatite ages are consistent with known high level microgabbroic intrusives on Helen's Reef and could also be derived from basement rocks of very ancient terrains. Minor contributions were identified ..