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New Zealand’s Sedimentary Basins

The islands of New Zealand have a total area of 250,000 square kilometres and are the emergent parts of an extensive, mainly submerged continental landmass with a total area of 6 million square kilometres. Northwest, south and east of New Zealand are large areas of relatively shallow sea underlain by plateaux and ridges that border the deep ocean basins of the Pacific Ocean and Tasman Sea.

Map showing the location of sedimentary basins in New Zealand

New Zealand established an Exclusive Economic Zone (EEZ) defined by a line 200 nautical miles from the New Zealand coastline and, under the United Nations Convention on the Law of the Sea (UNCLOS), also defined an Extended Continental Shelf (ECS) beyond the EEZ. In August 2008, a United Nations Commission confirmed the extent of New Zealand’s maritime entitlement. New Zealand now has sovereign rights over more than 5.7 million square kilometres of seabed. This is an area 22 times greater than our land area; equivalent in size to the European Union, the North Sea, and a quarter of the Mediterranean combined. A large area of New Zealand’s offshore territory is covered only by reconnaissance geophysical surveys, however the available data suggest large sedimentary basins that may host oil and gas cover about 20% of New Zealand’s territory - over a million square kilometres.

The New Zealand sedimentary basins can be subdivided into "Petroleum Basins", and "Frontier Basins . For the "Petroleum Basins", the present understanding is based on modern, industry-standard seismic surveys over at least a part of each basin (e.g., Deepwater Taranaki 2001–2009, Raukumara 2005–2007, Reinga 2009 and Pegasus 2010) and, for all except Pegasus and Raukumara, on well logs. All or part of each "Petroleum Basin" has been licensed for exploration. Large parts of some basins (for example, the outer Canterbury Basin) remain poorly known and are considered frontier regions; in such areas there is little or no industry-standard seismic.

The basin boundaries are mainly determined by major geological structures or seafloor physiography. In general, regions with stratigraphic continuity and a common geological history are included within a single basin. In places, the basin limits are set at a minimum sediment thickness. For some, sub-basins and provinces can be differentiated on geological or geographical criteria respectively.

The Cretaceous-Cenozoic basins are widely distributed around the New Zealand landmass, particularly offshore. At present, the only commercially producing fields are in the Taranaki Basin. See our Paleogeographic Maps for Paleogeographic reconstructions of the New Zealand landmass and offshore sedimentary basins from the Cretaceous to present day.

Data Products and Field Trips are available for many of these regions.

Contact the Ministry of Economic Development for information about current and upcoming licensing rounds, and currently permitted blocks.