Geology of the pre-Cenozoic basement of the Taranaki-Cook Strait-Westland area, New Zealand, based on recent drillhole data

Abstract

Nine wells drilled in the Taranaki-Cook Strait-Westland area intersected pre-Cenozoic basement or basement-derived material. Petrological examination of cores and cuttings from these wells suggests that the Rotoroa Igneous Complex, the Separation Point Batholith, the NW Nelson Paleozoic metamorphic rocks, and possibly the Karamea Batholith extend from the South Island in a N-NNE direction beneath the Cenozoic cover. The trend of these rocks parallels the western margin of the New Zealand Geosyncline, supporting the suggestion that they constituted a foreland region during the development of the Geosyncline in the North Island, and were an important source of clastic material within it.