INTEGRATED NEOGENE TO QUATERNARY NANNOFOSSIL BIOSTRATIGRAPHY AND SEDIMENTATION RATES ANALYSIS IN THE CIKARANG SEQUENCE, NORTH WEST JAVA BASIN, INDONESIA

Nannofossil assemblages were found throughout the Neogene to Quaternary rock sequence at Cikarang in the Northwest Java Basin, Indonesia. This study determines the biostratigraphic age, reconstructs depositional phases and calculates the sedimentary rate of the rock sequence based on lithology and nannofossil assemblages. Within this sequence, 59 nannofossil species can be identified and 14 are index fossils with easily recognizable first occurrence (FO) or last occurrence (LO). Based on these boundaries, the sequence is divided into 17 biostratigraphic zones categorized into range and interval zones. Lithology successions in Cikarang are generally composed of fine-grained clastic rocks (sandstone and claystone), clastic limestone and fossil reefs, which are deposited in various depositional environments such as deep marine, shallow marine and littoral. Sedimentation rates vary between 4.18 m/Myr to 217.87 m/Myr, reflecting the influence of tectonic activity, sea level changes and sediment supply. Unconformities are identified at the intra Miocene, as well as Mio-Pliocene and Plio-Pleistocene boundaries.