Eocene-Miocene high latitude biostratigraphy

Abstract Studies of high-latitude planktonic foraminiferal faunas indicate that certain biostratigraphic problems may be resolved by the application of bioevents among the three microperforate families, Guembelitriidae, Chiloguembelinidae and Tenuitellidae. With the aid of the scanning electron microscope, these small tests appear to be useful stratigraphic markers in the condensed sequences of deep-sea cores, where their evolution can be correlated with magnetostratigraphy. In the early-mid-Eocene, the Jenkinsina-Cassigerinelloita lineage assists the recognition of zones based on the larger, muricate Acarinina . Four zones are proposed in a revised lineage zonation of the tenuitellids, presented as a complementary biostratigraphic scheme for differentiating the Eocene-Oligocene boundary interval in high latitudes: (1) the Praetenuitella insolita Zone in the late Eocene; (2) the Tenuitella gemma Zone in the early Oligocene; (3) the Tenuitella munda Zone in the mid-Oligocene; (4) the Tenuitellinata angustiumbilicata Zone in the late Oligocene.