Lee JM, Begg, JG, Bland KJ. 2020. Geological map of the Napier-Hastings urban area. Lower Hutt (NZ): GNS Science. 1 map, scale 1:75,000. (GNS Science geological map 7a). doi:10.21420/XD8A-GS52
This 1:75 000 scale map provides updated geological mapping for the Napier-Hastings urban areas. New information includes detailed mapping of Pliocene–Quaternary-age rocks in the hills northwest of Napier and the Ngaruroro River, new formations introduced to encompass Holocene river and marine deposits, and revision of surficial and sub-surface traces of potentially active faults. The map provides geological context for the landscape features within this dynamic part of North Island’s east coast.
Rocks present in the map area record the development of the Hikurangi subduction margin and deformation associated with it. The oldest rocks present are Eocene to Miocene-age deep-marine mudstone and sandstone, distributed in fault-controlled northeast–southwest-trending strips east of Havelock North. Pliocene- to Quaternary-age shallow-marine limestone, mudstone, and sandstone overlie the Miocene rocks and form the hill country that immediately surrounds the Napier-Hastings urban areas. Conglomerate, pumiceous sandstone, carbonaceous mudstone, and volcaniclastic deposits of early to middle Quaternary age, are preserved at Cape Kidnappers, south of Havelock North, and as isolated remnants on hilltops west of Napier. Middle to late Quaternary alluvial fan and marginal-marine sediments were deposited by rivers and coastal processes. The Awanui and Tukituki faults are steeply-dipping reverse faults with surface traces exposed in the south of the map area but buried beneath the plains farther north.