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Palynostratigraphy, Paleoecology and Paleoclimatology of Early Pleistocene Based on Pollen Study of Pucangan Formation in Sangiran Area Yulianto, Eko; Sri Sukapti, Woro; Setiawan, Ruly
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 3 (2019): Article in Press
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (201.307 KB) | DOI: 10.33332/jgsm.geologi.20.3.133-141

Abstract

A pollen study has been conducted on samples taken from Pucangan Formation in Sangiran area. This study aims to reconstruct palynostratigraphy and to reveal environmental dynamics along with the deposition of Pucangan Formation with an emphasis on the influence of high frequency volcanism to the vegetational landscape in the montane area. The co-occurrence of Phyllocladus hypophyllus and Podocarpus imbricatus indicates Plistocene age of samples, and their stratigraphic position overlied by Middle Pleistocene Kabuh Formation leads to a conclusion of Early Pleistocene. All samples are included in Monoporites annulatus Peak Zone and subdivided into three Peak Subzone i.e. Polypodisporites radiates, Psilotum nudum, Magnastriatites grandiosa, Cyathea sp. and Laevigatosporites sp. Concurrent Peak Subzone, Interval Subzone between two Peak Subzones i.e. Polypodisporites radiates, Psilotum nudum, Magnastriatites grandiosa, Cyathea sp., Laevigatosporites sp. Concurrent Peak Subzone and Casuarina sp. Peak Subzone. Along with the deposition of Pucangan Formation, savannah with sparse swamp, riparian and lowland forest spreaded out around particularly on lowland, while few mangrove forest grew on muddy sea-land interface environment and heterogenous montane forests occupied highland. During the deposition of stratigraphic profile, savannah got flourished on new emerged land due to regression. Frequent volcanic eruptions along with the deposition of the upper stratigraphic profile has destroyed heterogenous montane forest and led to the homogenous Casuarina junghuniana forest.Keywords: Palynology, Early Pleistocene, vegetational landscape, savannah, montane forest, regression, volcanism
The Magnetostratigraphy and the Age of So’a Basin Fossil-Bearing Sequence, Flores, Indonesia Yurnaldi, Dida; Setiawan, Ruly; Patriani, Emma Yan
Indonesian Journal on Geoscience Vol 5, No 3 (2018)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1741.172 KB) | DOI: 10.17014/ijog.5.3.221-234

Abstract

DOI: 10.17014/ijog.5.3.221-234Three fossil-bearing intervals have been recognized in the Pleistocene So’a Basin, with the upper one holding important evidence of hominin fossils. The sequence also contains numerous in situ stone artifacts and fossils of other vertebrate taxa. Therefore, multiple dating techniques are crucial to secure the age of the fossil and artifact-bearing layers, especially the one with the hominin remains. This paper deals with the palaeomagnetic dating of the So’a Basin sequence to assist other dating methods that have been applied, and to refine the chronostratigraphy of the area. Palaeomagnetic sampling was conducted in four sections along a west to east transect. Four magnetozones can be recognized, consisting of two reverse and two normal polarity zones. By using the available radiometric ages as a guide and comparing the So’a Basin magnetostratigraphy with the Standard Geomagnetic Polarity Time Scale (GPTS), it became clear that both reverse magnetozones are part of the Matuyama Chron, while the normal magnetozones are the Jaramillo subchron and the Brunhes Chron. These palaeomagnetic dating results support the available radiometric dates and refine the age of the fossil-bearing deposits of the So’a Basin.