Late Oligocene c.25Ma

Late Oligocene map

Increasingly oblique extension in south, and southwards propagation of Pacific subduction zone east of proto-North Island. Pervasive subsidence, and maximum marine inundation of New Zealand sub-continent. Extensive shallow marine platforms. Minimal land area and clastic sediment supply. Widespread deposition of carbonates (seal rocks, or potential fractured reservoirs).

The present-day 2000 m isobath, which nominally marks the periphery of the New Zealand sub-continent, is used for reference (boundary between dark blue and mid blue). Bold line depicts paleo-coastline.

Colour coding: white = terrestrial non-deposition; yellow = marginal marine sand-dominated facies; pale blue-grey = shelf; mid-blue = slope or submarine rise; dark blue = deep ocean. Faults, subduction zones, and seafloor spreading centres shown in red. Pink circles = active volcanism.

Basins depicted include: Taranaki (TB), East Coast (ECB), Canterbury (CB), Great South (GSB), and Western Southland (WS).

To view individual maps, click below:

Download animation of all maps deforming in sequence over 65 million years.