Tertiary stratigraphic palynology in Southeast Asia: current status and new directions

Abstract

Palynology is the only biostratigraphic technique which permits crossfacies correlation, and the only micropalaeontological method for correlation of non-marine sediments. Despite its wide use in Southeast Asia, there is currently very little published information which allows the geologist to assess independently the value of palynology for correlation and dating in this area. It is hoped that this contribution will help to fill this gap, as well as indicate the groundwork which is necessary in order to build up correlation schemes which will be of value in individual basins.Following a brief review of the history of palynological research in Southeast Asia, differences in approaches to correlation and dating of Tertiary sediments using palynology and other micropalaeontological disciplines are outlined. It is emphasised that in the Tertiary, the application of palynology is principally in correlation rather than dating; ages can often be applied to palynological zones only through independent dating using planktonic microfossils associated within transgressive sequences and distal marine facies.The resolution of palunological zonation schemes currently applicable to the Southeast Asian region and which are based on age restricted palynomorphs is then discussed. Many of the most important age index palynomorphs actually exhibit varying stratigraphic ranges across the region and these variations can often be explained in terms of tectonic, climatic and other controls. There is some scope for the determination of additional stratigraphic markers, especially in the Palaeogene, but high resolution schemes based on stratigraphically restricted form, if they can be established, will require a great deal of work.In order to provide palynological schemes of sufficient resolution to solve typical questions raised during petroleum exploration in Southeast Asia, an approach is required which gives greater resolution than is possible through reliance on age restricted palynomorphs alone. The methods and philosophy behind quantitative palynological zonation schemes are outlined and the stratigraphic resolution of quantitative and qualitative methods compared. Quantitative schemes can provide stratigraphic resolution comparable to that of planktonic marine microfossils, and greatly assist in the resolution of stratigraphic problems and search for hydrocarbons in non-marine, marginal marine and some marine depositional sequences.

Palaeoecology of Southeast Asian megafauna‐bearing sites from the Pleistocene and a review of environmental changes in the region

“…The climate of Java during much of the Miocene is thought to have been wet and warm, and land would have been covered mostly by rain forest and peat‐swamps (Morley, 1991, 2000; Whitten et al. , 1996).…”

Palynological and paleobotanical investigations of Paleogene sections in the Maoming basin, South China

“…Exten sive information on Paleogene and Cenozoic (mostly Oligocene and Miocene) low latitude floras of China has recently been obtained in Yunnan, Guangxi, and Fujian provinces and on Hainan Island (Jin, 2009;Jin et al, 2009Jin et al, , 2010Yao et al, 2009;Shi and Li, 2010;Xie et al, 2010;Xing et al, 2010;Su et al, 2011;. For a long time, the Cretaceous and Paleo gene-Neogene climate and floras of southeastern Asia have been investigated by R. Morley using palynological data (Morley, 1991(Morley, , 1998(Morley, , 2000(Morley, , 2001.…”

Palaeoenvironmental setting of MojokertoHomo erectus, the palynological expressions of Pleistocene marine deltas, open grasslands and volcanic mountains in East Java

“…In addition, a more precise minimum age is suggested by the occurrence of rare specimens of S. milnei type spores (Figure S1.13) in the uppermost portion of Mollusk Member II, bottomset and topset beds of the Perning Delta Lobe, as high stratigraphically as 30 m below the H. erectus discovery bed. The extinction of S. milnei type was previously dated to approximate the Plio‐Pleistocene boundary at 1.95 Myr (Morley, ). However, work carried out by the authors (RJM and HPM) on the late Neogene biostratigraphy of thick stratigraphic sequences penetrated by petroleum exploration wells in East Kalimantan (where the Plio‐Pleistocene is particularly well developed) consistently recorded the S. milnei type as young as the extinction of the nannofossil Calcidiscus macintyrei , while it was consistently missing in younger strata.…”

“…Answers to these questions have been obtained by applying the method of sequence biostratigraphy to the succession, which facilitates reconstruction of a catchment landscape within a framework of transgressive‐regressive cycles based on the combined evaluation of microfossil assemblages and the lithological succession (Armentrout et al, ; Morley, ; Morley et al, ). The stratigraphic profile includes fully marine and terrestrial sediments and the comparison of pollen assemblages in these different facies in tropical deltas allows judgement of the representation of ‘local’ and ‘regional’ pollen components (Morley, ), that enables identification of the likely pollen sources. This allows judgement to be made of the representation of coastal and inland vegetation across the broad catchment area (Figure b).…”