The influence of basement structure on the evolution of the Taranaki Basin, New Zealand

The Taranaki Basin, situated offshore western New Zealand, is one of severa l large sedimentary basins formed during the Late Cretaceous in response to break-up of the palaeo-Pacific margin of Gondwana. A review of published s tructural, stratigraphic and geochronological data indicates that NE to NNE striking basement faults, generated during Palaeozoic to Mesozoic terrane accretion along the Gondwana margin, have strongly influenced the developme nt of the basin. The main basin-bounding faults, the Cape Egmont Fault Zone and the Taranaki Fault, correspond to the boundaries of a narrow bell of p lutonic rocks known as the Median Tectonic Zone. Geological data from onsho re South Island suggests that right-lateral movement occurred along the bou ndaries of the Median Tectonic Zone during the Early Cretaceous. From the L ate Cretaceous to Early Tertiary, NE to NNE striking normal faults within t he Taranaki Basin controlled deposition in a series of en-echelon half-grab ens and sub-basins. Many of the normal faults were later reactivated during a phase of compressional deformation associated with the development of th e Australian-Pacific plate boundary through New Zealand. Reverse movement o n the Taranaki Fault began in the early Miocene and deformation propagated westward reaching the Cape Egmont Fault Zone in the late Miocene to early P liocene.