Cenozoic sedimentary sequences of SE Asia are dominated by warm water, shallow marine carbonates. These formations are of crucial importance: they are the product and record of climatic/oceanic conditions and interchange in tropical/subtropical inner shelf environments, and are also major hydrocarbon reservoirs. These deposits are dominantly biogenic in origin, being primarily composed of larger foramininifera and algae, with hermatypic corals.
Larger benthic foraminifera have been used extensively for biostratigraphical, palaeoceanographical and palaeoclimatological applications. As early as the late 1920s, the larger foraminifera had become the preferred fossil group for biostratigraphy in the Indonesian area. They have since been used extensively in the Far and Middle East, as markers for biostratigraphical zonation and correlation, underpining most drilling of marine sedimentary sequences, as well as for hydrocarbon exploration.
We regularly use the study of foraminifera in thin sections and washed residues to define the biostratigraphy of SE Asia. Our work using biostratigrpahy is routinely carried out in conjunction with Dr Marcelle BouDagher-Fadel at University College London. Building on both current and recent projects we intend to carry out a regional synthesis based on existing local studies.
Completed SEARG projects utilising biostratigrpahy:
- Stratigraphy of the Togian Islands, and their role in the evolution of the Gorontalo Bay
- Paleogene and Early Miocene geological evolution of West Java
- Neogene Basin Evolution in a Volcanic Arc Setting
Larger benthic foraminifera develop complicated endoskeletons, which are reproduced precisely with each successive generation. They are important rock forming materials, and foram-limestones are extensively developed in the upper Palaeozoic, the upper Cretaceous and in the Cenozoic.
They are confined mainly to low-latitude areas and are most prolific in warm, shallow-water situations. From their structural complexity, and because of the diversity of the shelf environments that they inhabited, no other microfossils can provide such complete and detailed evidence of taxonomic, phylogenetic evolution, applicable to palaeoenvironmental and biostratigraphic analysis of the shelf limestones of the Middle and Far East.
The role of the planktonic foraminifera as markers for biostratigraphical zonation and correlation in the Far East underpins most drilling of marine sedimentary sequences as well as being key to hydrocarbon exploration.
Many species of foraminifera are planktonic and of worldwide occurrence in broad latitudinal and temperature belts. Their wide distribution and rapid evolution are a reflection of their successful colonisation of the pelagic realm. When this wide geographical range through the late Mesozoic and Cenozoic is combined with a short vertical time range they make excellent index fossils at both the family and generic levels.
Planktonic foraminifera fossils usually are easily extracted from pelagic sediments, however when they occur in interdigitated hemipelagic carbonates, they can only be studied by thin sections.
BouDagher-Fadel, M.K., 2008. Evolution and Geological Significance of Larger Benthic Foraminifera, Developments in Palaeontology and Stratigraphy, 21, Elsevier, Amsterdam, pp 544.
Sharaf, E., BouDagher-Fadel M.K., Simo, T.A. and Carroll, A.R. 2006. Biostratigraphy and strontium isotope dating of Oligocene-Miocene carbonates and siliciclastics, east Java, Indonesia. Stratigraphy, 2,239-258.