OLIGOCENE PALYNOLOGICAL ZONATION  

Oleh:

Lelono, Eko Budi ; Morley, Robert

Jenis: Article from Journal - ilmiah nasional
Dalam koleksi: Lemigas Scientific Contributions to Petroleum Science & Technology vol. 34 no. 02 (Sep. 2011), page 95.
Topik: Oligocene; Palynological zonation; East Java Sea

Ketersediaan

Perpustakaan PKPM Nomor Panggil: L15 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

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Isi artikel

Systematic biostratigraphic analyses have been undertaken on the Oligocene clastic and carbonate Kujung Formation from the East Java Sea, North of Madura. The succession has been examined mainly using cutting samples in two wells, using a combination of foraminiferal, nannofossil and palynological analyses at regular spacing. Nannofossil analysis indicates that the Late Oligocene to basal Early Miocene succession is more or less complete, with zones NP24, NP25 and NNl are all being well developed. In addition, the Early Oligocene is indentified by larger foraminifera indicating the Tel Td Letter Stage. Because the traditional palynological zonation of Morley (1978) does not work well in this area, the succession has been divided into broad assemblage zones, which appear to be controlled mainly by climate. These zones are OL-l, OL-2, OL-3, OL-4 and OL-5. Zone OL-l is based essentially on the absence of seasonal climate and riparian elements, whilst zone OL-2 is characterized by the regular occurrence of seasonal climate elements, especially of Malvacipollis divers us. Zone OL-3 is indicated by common to abundant Dacrydium and Casuarinapollen, with a strong acme of dinoflagellate cysts dominated by Operculodinium spp. and Spiniferites spp., whereas zone OL-4 is marked by abundant Dacrydium and regular Casuarina pollen, representation of riparian elements. Finally, the youngest zone is OL-5 which is characterized by reduced Dacrydium and Casuarina pollen, and increased riparian elements. The above palynological zonation suggests climate change, which closely parallels the climate succession from WestJava Sea (but with changes less pronounced). Therefore, this study provides.a well dated Oligocene palynological zonatIOnwhIch can be applied across Java

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