Lower-Middle Miocene Biostratigraphy of the Siliciclastic Rambatan Formation, North Serayu Basin

Abstract

The discrepancies discovered in the findings of past researchers with respect to the depositional environment give rise to questions concerning the processes driving the deposition process and shifts in the depositional environment throughout the evolution of the Rambatan Formation. The present study was conducted in Cikadu Village, located in the Watukumpul District of the Pemalang Regency in Central Java, Indonesia. The primary purpose of this study is to evaluate the geological age and depositional environment of the Rambatan Formation in the chosen research location. The data suggest that the age of the rock units within the Lower Miocene - Middle Miocene period, namely within the N5 - N14 zones. Additionally, the research confirmed the presence of three indicator fossil species: Catapsydrax dissimilis, Globigerrinoides Altipelturus, and Globorotalia fohsi. In this work, paleobathymetry in the research area was measured by the use of benthonic foraminifera. The findings collected stretched from the Lower Bathyal to the Transition, and were verified by the discovery of peculiar fossils found in the Middle Neritic and Lower Bathyal environments, notably Nodosaria sp. and Sphaerodina bulloides. Ammonia beccarii, a characteristic fossil, was discovered in the transitional habitat, as described by several specialists. Based on these observations, it may be deduced that the depositional habitat runs from continental to slope.