Biostratigraphy and facies analysis of Jatibungkus olistolith (Central Java)

The Eocene Karangsambung Olistostrome (or mélange) contains numerous blocks of different sedimentary, volcanic and metamorphic rocks, up to several hundreds meters in diameter; among these olistoliths, we investigate the fossil content, sedimentology, facies interpretation and age assignment of the huge Jatibungkus limestone olistolith, which has been subject to contrasting interpretations. Basing on larger foraminifers (Ranikothalia, Miscellanea, rotaliids, and orthophragmines), scleractinians (11 species belonging to 9 genera) and calcareous algae, the Jatibungkus limestone can be broadly considered as Thanetian in age (SBZ3/SBZ4). On the base of thin sections, the taxonomy of the larger foraminifers is discussed in detail, attempting to constrain and extend to this area the Shallow Benthics Zonation. Basing on sedimentological data, the occurrence and growth forms of Distichoplax biserialis, the scleractinian and larger foraminiferal assemblages allow us to identify three main depositional environments.