Silicoflagellate abundance in ODP Holes 162-982B and 162-907B@en

Silicoflagellate assemblages were analyzed for the Miocene intervals recovered during Ocean Drilling Program (ODP) Leg 162. The middle and late Miocene are represented in Holes 907B (Iceland Plateau) and 982B (Rockall Plateau) by well-preserved silicoflagellates. A zonal scheme is presented, which improves previous attempts to establish a comprehensive silicoflagellate stratigraphy for this realm, based on an increased resolution given by the analysis of this largest-ever number of samples for the given interval (about three times as many as those studied for ODP Leg 104). The most important change is the replacement of the last appearance of Corbisema triacantha by the first appearance of Bachmannocena circulus apiculata as the top of the upper C. triacantha Zone/bottom of the B. c. apiculata Zone. In addition, two important bioevents (the first appearance of Bachmannocena diodon nodosa and the last appearance of Distephanus crux stradneri) allow the subdivision of the B. c. apiculata Zone into three new subzones: Caryocha spp. Subzone, D. c. stradneri Subzone, and B. d. nodosa Subzone (oldest to youngest, respectively). This zonal scheme is correlated with the standard calcareous nannoplankton zonation and tentatively correlated with the magnetic polarity time scale. […]