THE BAGELEN BEDS, CENTRAL JAWA

P. Lunt (Lundin Blora b.v., Jakarta (now Murphy Oil, Kuala Lumpur))
H. Sugianto (Lundin Blora b.v., Jakarta (now PT. Sumatera Persada Energi, Jakarta))

Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources)
Vol. 17 No. 5 (2007): Jurnal Sumber Daya Geologi

The Bagelen Beds of Cential Java are re-defined and described as a very deep marine olistostrome deposit of Early Oligocene age (about 321/2 MYBP).  There is no indication that the clays have been tectonised and they are considered a pebbly-claystone or slump deposit rather than a tectconic melange.The benthic microfaunas are analogous to those found in open-ocean palaeobathymetries at around 3,000 metres, but it is argued that this interpretation may not be applicable to semi-restricted basins in a tectonically complex area. A shallower depth,of very roughly 1,000 to 2,000 m, is argued to be possible and that this would better fit tile epi-cratonic geological setting. The significance of a deep marine, slump-filled environment in the Early Oligocene of Central Java is discussed, and a suggestion made for the origin of the unusual  mud-volcano found in the Sangiran Dome. Keywords: Bagelen beds, Olistostrome, slum deposit benthic microfaunas, epi-cratonic