Early to middle eocene radiolarian biostratigraphy for the low-latitude South Atlantic Ocean (Brazil Basin, DSDP Leg 39, Site 355)

The analyses of radiolarian assemblages were carried out from low-latitude DSDP Site 355 (Leg 39), drilled in the Brazil Basin, South Atlantic Ocean. A total of 98 early to middle Eocene radiolarian events were identified in this site. The standard low-latitude radiolarian zonation was adopted for the Site 355 cores, and it allowed the identification of seven radiolarian zones: Podocyrtis mitra (RP14), Podocyrtis ampla (RP13), Thyrsocyrtis triacantha (RP12), Dictyoprora mongolfieri (RP11), Theocotyle cryptocephala (RP10), Phormocyrtis striata striata (RP9), and Buryella clinata (RP8). The radiolarian events at Site 355 were compared with previous studies from low and mid-latitudes, showing a good correlation with the low-latitude regions. On the other hand, 11 radiolarian events were clearly diachronous between low and mid-latitudes.