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POLLEN RECORD OF THE PERMIAN MARINE SEDIMENTS FROM WEST TIMOR Eko Budi Lelono
Scientific Contributions Oil and Gas Vol 40 No 2 (2017)
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/SCOG.40.2.42

Abstract

This is the fi rst publication to present palynological study on the Permian marine sediments of West Timor. This is aimed to evaluate its palynomorph content. Similar studies have been performed on the Permian sediments which mostly focus on non-marine sediments. 15 surface samples were collected from Lilana river outcrop which comprises the alternation of calcareous shale and sandstone. This outcrop is assumed to represent some parts of Bisane Formation. Standard preparation methods were employed to extract palynomorphs including acid maceration and oxidation. This study applies quantitative method which requires counting of palynomorphs in each sample. This study provides low to moderate pollen recovery which mostly consists of striate and non-striate bisaccates as well as trilete monosaccates. The age restricted taxa appearing in the non-marine sediments also present in the studied samples to mark Permian age such as Protohaploxypinus samoilovichi, Lunatisporites pellucidus, Falcisporites australis, Plicatipollenites malabarensis and Cannanoropollis janakii. On the other hand, common occurrence of marine dinofl agellates of Dapsilidium langii and Veryhachim reductum combined with abundant macrofossil of chrinoids confi rm a shallow marine paleoenvironment. Common green algae of Tasmanites sp. is a firmed evidence for the appearance of potential source rock of hydrocarbon within the Permian shallow marine sediments of West Timor.
POLLEN RECORDS FROM THE OLIGOCENE OF WESTERN INDONESIA AS THE EVIDENCES OF CLIMATE CHANGES Eko Budi Lelono
Scientific Contributions Oil and Gas Vol 40 No 3 (2017)
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/SCOG.40.3.46

Abstract

In Southeast Asia, Oligocene climate is well known to be represented by dry/ seasonal climate. However, it was reported possible appearance of wet climate period during the expantion of dry condition. This work is aimed to confi rm the Oligocene climate which occurred in western Indonesia. Climate change is useful to understand the Oligocene stratigraphy of Western Indonesia. This study uses cutting samples from off shore exploration wells situated in West and East Java and West Natuna as well as on-shore Central Sumatera and West Java. Samples are processed using standard preparation methods to produce suitable pollen assemblage for quantitative analysis.This study proves that the Oligocene sediments yield rich pollen assemblages including those of environment and climate indicators. Abundant fresh water algae of Pediastrum and Bosedinia in Early Oligocene indicates the appearance of lacustrine sediments. This sediment was formed under dry/ seasonal climate as marked by rich grass pollen Monoporites annulatus in the absence or rare occurance of rain forest elements. Mean while, Late Oligocene is characterised by common brackish elements to indicate shifting paleoenvironment into transition to shallow marine. The climate was changing into wetter condition as evidenced by high appearance of Dacrydium and Casuarina as well as other rain forest palynomorphs. The wettest climate probably occured in Java region which refl ected a wet climate fringe to the eastern margin of Sundaland prior to the collision of the Australian and Asian Plates at the Oligo-Miocene boundary. However, in general, dry/ seasonal climate is the rule for most of the Oligocene in Western Indonesia.
DRY CLIMATE EXPANSION ON THE PLEISTOCENE OF INDONESIA AS RECORDED IN ITS POLLEN ASSEMBLAGE Eko Budi Lelono
Scientific Contributions Oil and Gas Vol 41 No 1 (2018)
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/SCOG.41.1.69

Abstract

Most researchers agree that Pleistocene is characterised by glacial and inter glacial periods which are strongly related to dry/ cool and wet/ warm climates. Apparently these are refl ected on their pollen records. The period of dry climate (glacial climate) is characterised by abundant Gramineae pollen, whilst the period of wetter climate (interglacial climate) is indicated by an increase of coastal and mangrove palynomorphs, but greatly reduced frequencies of Gramineae pollen. On the contrary, previous works on the Pleistocene sediments of Java indicated high abundance of grass pollen along this age marking drier climate condition. This paper publishes the study which is intended to evaluate paleoclimate of Java and other area of Indonesia during Pleistocene. For this purpose, some well samples from East Java and Papua were collected. Standar laboratory preparation was employed to extract pollen from the cutting samples. This study applies quantitative method which allows detail climate change interpretation. This study shows that Pleistocene of East Java is characterised by abundant grass pollen of Monoporites annulatus which may correspond to the period of expansion of savanna vegetation coinciding with glacial period. More over, it is indicated by abundant charred Gramineae cuticles which derive from burning grass. This might have been caused by extreme heat which could relate to the volcanic activities existed in East Java. Slightly different record appears in Papua which shows repetition of dry/ wet condition or low/ high sea level. The moist climate related to the phase of sea level rise is marked by abundant brackish pollen which possibly represented interglacial period. It is also supported by the increase of peat swamp and freshwater palynomorphs. On the other hand, dry climate representing glacial period is defined by significant decrease of these brackish and freshwater elements.