Evolution of the central Exmouth Plateau: a post-drilling perspective

Abstract

Well-constrained dating of the unconformities associated with tectonic events has narrowed considerably the age of the final fragmentation of the plateau to late Valanginian. Sequence-stratigraphic concepts applied to the Berriasian Barrow Group sediments have revealed the presence of several depositional sequences (at least four in the cored part of Site 763) and provide a valuable case study of an ancient lowstand prograding complex with high clastic influx. Refined multifossil biostratigraphy for much of the recovered Cretaceous and Cenozoic section was possible. Attempts at paleomagnetic analyses produced an incomplete but partially useful magnetostratigraphic record of the Late Cretaceous and Cenozoic. An essentially complete Paleogene and nearly complete Neogene record is present at Site 762 which lent itself to detailed biostratigraphic zonation. Given the good palynological (microplankton) biostratigraphic resolution available for the Neocomian part of the section, but less than definite correlation to global biostratigraphic schemes, the timing of sea-level events on the central Exmouth Plateau appear to agree well with the eustatic cycle chart, suggesting a global influence superimposed on the local and regional tectonics. -from Authors