The extinct Ngatutura volcanic field that was active between 1.54 and 1.83 million years ago [3][2] is one of four volcanic fields in an intraplate back arc relationship with the still active Hauraki Rift and the presently dormant Auckland volcanic field.

[4] and to the north the younger South Auckland volcanic field.

[5] This field is smaller than the other three and has far fewer basaltic volcanic centres.

[1] Some of the basalt deposits in this region of the coast are now known to be related to the West Ngatutura volcanic field with a stratigraphic age of c. 3.5 Ma around 60 km offshore.

[2][5] The earlier work on the field had suggested fewer centres being:[6]