Maunganui Bluff is a prominent coastal bluff located on the west coast of New Zealand's

North Island The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...

, in the

Northland region Northland (), officially the Northland Region, is the northernmost of New Zealand's 16 regions of New Zealand, local government regions. New Zealanders sometimes refer to it as the Winterless North because of its mild climate all throughout t ...

. Known locally as ''The Bluff'', it is set in a scenic reserve and rises above sea level. Maunganui Bluff marks the northern extent of long Ripiro Beach (the longest unbroken beach in New Zealand).

Etymology

''Maunganui'' in

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the Co ...

means ''big mountain''.

Geology

Studies using remote sensing indicate these basalt layers form part of an eroded basalt shield volcano, originally centered about 10 kilometers west of Maunganui Bluff, with an estimated width of 50 kilometers. Comparatively, other Miocene basalt shield volcanoes, such as those at

Banks Peninsula Banks Peninsula () is a rocky peninsula on the east coast of the South Island of New Zealand that was formed by two now-extinct volcanoes. It has an area of approximately . It includes two large deep-water harbours — Lyttelton Harbour a ...

, Dunedin, and the

Auckland Islands The Auckland Islands ( Māori: ''Motu Maha'' "Many islands" or ''Maungahuka'' "Snowy mountains") are an archipelago of New Zealand, lying south of the South Island. The main Auckland Island, occupying , is surrounded by smaller Adams Island ...

, each spanned roughly 20 to 30 kilometers. View from Maunganui Bluff

Maunganui Bluff and the Waipoua Forest region are primarily composed of Early Miocene basalt flows that include pyroclastic deposits, volcanic breccia,

dikes Dyke or dike may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), formations of magma or sediment that cut through and across the layering of adjacent rocks * Dike (mythology), ''Dikē'', the Greek goddess ...

and breccia dikes. This local formation is referred to as Waipoua Basalt. Maunganui Bluff consists of layered basalt flows between 2 and 10 meters thick, interspersed with thin beds of rubbly breccia and oxidized volcanic ash. Numerous vertical dikes, formed from intruding basalt lava, cut through these layers, representing fractures within the ancient Waipoua shield volcano during its formation.

References

{{Reflist Headlands of the Northland Region Kaipara District