Brook, F.J.; Hayward, B.W. 1989 Geology of autochthonous and allochthonous sequences between Kaitaia and Whangaroa, northern New Zealand. Lower Hutt: New Zealand Geological Survey. Record / New Zealand Geological Survey 36 44 p.
Abstract:
In the area between Doubtless Bay, Whangaroa, and Omahuta, an autochthonous sequence of pre-Cretaceous basement (Waipapa Group), and unconformably overlying mid to late Eocene marine sediments (Te Kuiti Group), is overlain at a decollement surface by a sequence of allochthonous units. The latter sequence incorporates sedimentary units of early Cretaceous to Oligocene age (Tupou, Mangakahia, and Motatau complexes), and a volcanic-sedimentary unit of early Cretaceous to early Tertiary age (Tangihua Complex). The allochthonous units form a series of nappes that are inferred to have been emplaced during the early Miocene (Waitakian to Otaian), by gravity sliding on top of a passive autochthon. Allochthonous transport was predominantly to the southwest; nappes were apparently derived from an area off the coast of present-day northeastern Northland. A tectonic event within Northland immediately subsequent to nappe emplacement (Otaian), caused uplift, folding and faulting of both the allochthonous and autochthonous sequences. It was followed, in the Whangaroa and Doubtless Bay areas, by calc-alkaline eruptions from a number of volcanic centres (Whangaroa Group: Otaian to Altonian). In the mid to late Miocene, northeastern Northland was tilted to the northeast; terretrial to marginal marine sediments (Manganui Formation) accumulated locally on the resultant erosion surface. Basalt (Kerikeri Volcanic Group) was erupted from a number of small centres south of the Whangaroa area, during the ?late Pliocene, and Pleistocene (auth)
