LINGKUNGAN PENGENDAPAN FORMASI KALIBENG PADA KALA MIOSEN AKHIR DI KABUPATEN DEMAK DAN KABUPATEN SEMARANG, JAWA TENGAH BERDASARKAN RASIO FORAMINIFERA PLANGTONIK DAN BENTONIK (RASIO P/B) - Jurnaliah, Lia; Muhamadsyah, Faizal; Barkah, Mochammad Nursiyam (Fakultas Teknik Geologi Universitas Padjadjaran, 2016)
Research area is classified a Lower Kalibeng Formation. Its age is Lower Miocene. The total number of sediment samples is 29 samples that are carried out based on measured section with 10 metres interval. The whole samples are processed by hydrogen peroxide method. Foraminifers’ quantitative analyses is conducted on each one gram of dry sample. Based on ratio P/B value that range between 49.64% - 99.41%, Late Miocene Kalibeng Formation is deposited on marine environment. The depositional process is beginning from neritic (outer neritic) – oceanic (upper bathyal-lower bathyal) – neritic (outer neritic) - oceanic (upper bathyal – lower bathyal). Keywords: Kalibeng Formation, plangtonic and benthic foraminifera, neritic, oceanic Daerah penelitian merupakan Formasi Kalibeng bagian bawah berumur Miosen Akhir.. Pengambilan 29 sampel sedimen dilakukan secara sistematis berdasarkan penampang terukur dengan interval 10 meter. Seluruh sampel sedimen diproses dengn menggunakan metoda hydrogen peroksida. Analisis kuantitatif foraminifera dilakukan pada setiap 1 gram sampel kering berukuran >120 mesh. Berdasarkan hasil perhitungan rasio foraminifera plangtonik dan bentonik (rasio P/B) yang berkisar antara 49,64% - 99,41%, Formasi Sungaibeng Kala Miosen Akhir terendapkan pada lingkungan marin dimulai dari neritik (neritik luar) – oseanik (batial bawah-batial atas) – neritik (neritik luar) dan terakhir adalah oseanik (batial bawah-batial atas). Kata Kunci: Formasi Kalibeng, foraminifera plangtonik dan bentonik, neritik, oseanik