Publications

Obtaining confident age interpretations using a traditional biostratigraphic approach fail in many of the Southeast Asian continental margin and lacustrine successions since most of the microfossil extinction datums are diachronous, or index fossils may be missing. This is due to a combination of facies and carbonate dissolution issues. In marine-influenced continental margin sediments sequence biostratigraphy allows confident age interpretations through the identification of transgressive-regressive cycles (SEA cycles) that faithfully capture the sedimentation ’pulsebeat’. These cycles are driven by patterns of Antarctic glaciation in the Oligo-Miocene and northern hemisphere glaciations in the Pliocene. In late Eocene and Oligocene non-marine basins on the other hand, such as occur across the Sunda Shelf, depositional cycles are driven solely by eccentricity-driven climate oscillations since marine influence is missing. Depositional cycles can be identified through the integration of systems tract-related signals from combining foraminifera and palynology, and palynology alone in non-marine basins. Cycles are ‘fingerprinted’ by reference to age-restricted microfossils in distal facies with correlations relying on sequence boundaries rather than first or last microfossil appearances. Within the Neogene, the SEA cycle succession captures the pulsebeat of depositional cycles and demonstrates that other sequence biostratigraphic schemes, such as the TA and TB cycle scheme of Haq and the scheme of Hardenbol, incorporated into the ICS global chart, include a mixture of cycles of different rank, and are thus less useful for stratigraphy prediction. In Palaeogene non-marine basins such as the Cuu Long and Song Hong in Vietnam, 406 kyr eccentricity-driven astronomical cycles provide that pulsebeat and allow the accurate determination of the age of otherwise difficult-to-date fluvial and lacustrine successions in the numerous rift basins across the region.