Nannofossil Biostratigraphy of Elat Formation, Kei Besar Island, Southeast Maluku

Abstract The first detailed mapping and recording of nannofossils was carried out on Kei Besar Island, Southeast Maluku. This area is mostly composed the Elat Formation, which mainly by intercalated calcarenite calcareous claystone. Total 48 samples were taken three measured sections (Hollat, Ngurdu Mata Hollat). Samples prepared using smear slide method, then observed under a polarized microscope at 1000 x magnification. species identified. Several index selected to define biostratigraphic zones based their last occurrence. Three are identified, starting with oldest those are: Reticulofenestra umbilica zone (NP16; 43.06 38.7 million years ago), Helicosphaera compacta (NP17; 37.9 Mya) eupratis (NP18-NP19; 37.9-36.8 Mya). It can be concluded that Formation deposited in Middle Late Eocene (43.06 35.4 Middle-Late boundary clearly defined assemblages section Island.