Seismic sequence stratigraphy and depositional evolution of the Cretaceous-Paleogene sedimentary successions in the offshore Taranaki Basin, New Zealand: implications for hydrocarbon exploration

Abstract The seismic stratigraphy and sedimentary facies of the Cretaceous Paleogene successions in north-eastern offshore part Taranaki Basin, New Zealand have been investigated order to unravel their depositional evolution identify potential hydrocarbon plays. Interpretation regional lines covering entire shelf-slope deepwater regions as well integrating allows identification several seismic-stratigraphic sequences within studied successions. Early syn-rift (C1 sequence) were deposited structural lows near present-day slope swamp marsh changing basinwards into turbidites marine shales. post-rift (C2, C3 sequences) started with progradation delta (C2A-C2D units) followed by sedimentation transgressive C3A-E accumulated response thermal subsidence high-rates clastic supply. Extensive shelf conditions prevailed during deposition C2 continued uniform shales throughout basin. Rates sediment supply substantially decreased Oligocene prompting micrite-rich carbonate. Variation fossil content confirms occurrence cycles sea level fluctuations episodic variations terrigenous input. Organic-rich could be associated prograding clinoforms C2B unit probably contain, basinward, large amount gas oil prone kerogen. C2D may also contain organic-rich basinward coal present day shelf. Potential reservoirs are hosted on estuarine sandstones. mudstones excellent seals for hydrocarbons generated trapped underlying Late facies.