[6] At least 5 of these contributed significant welded ignimbrite deposits that represent major pyroclastic events in the central North Island.

[2] Ongatiti Ignimbrite (Hinuera Stone) from a 7 VEI event,[7] about 1.3 million years ago, has now been found over a wider area and several meter thick tephra deposits from the eruption exist on drill samples from both Auckland and Wellington.

[14] The recognition was impaired mainly because of erosion produced discontinuities, burying by later volcanic deposits or overburden displacement in later caldera formation.

[15][16] What are now termed ignimbrites and manifest as prominent surface deposits, far from the complex, were recognised by Ferdinand von Hochstetter in his 1859 maps.

[17] Colin Wilson first defined the Mangakino caldera complex in 1984 and went on to improve the understanding of its ignimbrite distribution and stratigraphy.