Precision Dating and Correlation from the Malay Basin to Sabah Using SEA Depositional Cycles

Obtaining confident age interpretations using a traditional biostratigraphic approach fail in most continental margin successions since most microfossil extinction datums are diachronous due to a combination of facies and carbonate dissolution issues, whereas evolutionary appearances are affected by both facies and caving, and so there is invariable subjectivity in placement of such datums. Sequence biostratigraphy allows confident age interpretations through the identification of transgressive-regressive cycles (SEA cycles) that faithfully capture the sedimentation ‘pulsebeat’ driven by patterns of Antarctic glaciation in the Oligo-Miocene and northern hemisphere glaciations in the Pliocene, even in very deep-water settings. Cycles are ‘fingerprinted’ by age-restricted microfossils in distal facies with correlations relying on sequence boundaries rather than first or last microfossil appearances. Based on the evaluation of 101 biostratigraphic datasets from the Malay and Penyu Basins, offshore Sarawak and offshore Sabah, a total of 46 transgressive-regressive cycles are identified. The SEA cycle succession demonstrates that other sequence biostratigraphic schemes, such as the TA and TB cycle schemes include a mixture of cycles of different rank and are thus less useful for stratigraphy prediction. To undertake sequence biostratigraphic evaluations, biostratigraphers need to become equally familiar with all three biostratigraphic disciplines of micropalaeontology, nannopalaeontology and palynology