Print this pageDepositional History of the Taranaki Basin, New Zealand: Linking Sediment Accumulation and Subsidence Rates to Tectonic Processes
Geohistory analysis was performed in the Northern Graben of the offshore Taranaki Basin, located along the western coast of New Zealand’s North Island. The Taranaki Basin has a complex tectonic history, which is reflected in changes in Late Cretaceous to Cenozoic depositional patterns. Understanding the subsidence history and how it affected basin development is crucial to defining the structural and stratigraphic changes that took place during its evolution.
A reconstruction of the depositional history of the basin through seismic interpretation of about 630 km2 of the Parihaka 3D seismic volume and mapping of several horizons within the stratigraphic succession allowed identification of depocenters and spatial changes in thickness. This analysis is complemented by subsequent measurement of subsidence rates based on amount of sediment preserved, and a general description of the main structural and stratigraphic features observed during 3D seismic volume interpretation. Backstripping techniques were used to determine the tectonic subsidence after isolating the subsidence due to water and sediment load.
The Taranaki Basin was formed by extension associated with Tasman Sea spreading during the Late Cretaceous to early Oligocene. The basin was initially a rift basin, in which Late Cretaceous to Paleozoic typical synrift deposition was confined to half grabens and sediments were predominantly fluvial and shallow marine. A subsequent period of drift and quiescence, that started at late Paleocene deposited a large succession of Eocene mudstones while a carbonate platform developed for most of the Oligocene. This was followed by a Miocene compressional regime creating a deep basin filled with a thick and complex succession of deep marine sediments in a back-arc foreland basin related to the convergent plate boundary between the Australian and Pacific plates. Different types of subsidence (fault-controlled subsidence, thermal, and subsidence related to sediment load) are recognizable, as are periods of non-deposition.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil