Moore, P.R.; Francis, D.A.; Mazengarb, C. 1989 Geological Map of New Zealand, DSIR Sheet QM 303, Raukumara. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report G 138. 30 p.
Abstract
The 1:250 000 geological map of DSIR sheet QM303 Raukumara covers the onshore area of metric topographic maps X to Z, 14 to 18, and includes Otara River mouth (to the west), Cape Runaway (NW), East Cape (E), Gisborne, Mapere Point (SE), and Te Reinga (SW). Stratigraphic subdivision into new groups and formations is applied where recent detailed geological mapping data are available. Elsewhere, sedimentary rocks are mapped primarily on lithofacies with broad biostratigraphic subdivision. Thus important lithological changes are emphasized, in contrast to the biostratigraphic subdivision used in earlier 1:250 000 maps. Cretaceous to basal Tertiary rocks are subdivided into Urewera Group, Matawai Group, Tinui Group, 6 ungrouped formations, and large areas differentiated by biostratigraphic series (e.g., "C-R"). Paleogene rocks are included in the Mangatu Group, with 2 formations and several lithofacies. Miocene rocks are assigned to the Tolaga Group in the north and central areas, but termed "Miocene" to the south; both are subdivided lithologically where possible. Uppermost Miocene and Pliocene strata are mapped as Mangaheia Group (2 formations) in the central and northern areas, and to the south Pliocene rocks are lithologically subdivided. Quaternary strata are subdivided according to age and deposit type. Pre-Miocene rocks are divided structurally into the East Coast Allochthon (northern and eastern) and the autochthonous Motu Block (southwestern). Miocene to Pliocene rocks are extensively folded and faulted (dominantly normal) by NNE to ENE - trending structures, which were probably active during deposition. Quaternary tectonism is irregular to the SE, measured on the Holocene deposits, but relatively uniform to the NW, measured on 125 000 yr old surfaces. (auth)
