Strong, C.P.; Scott, G.H.; Morgans, H.E.G. 1993 Biostratigraphic review of selected drillholes, Hawkes Bay - Gisborne area. Lower Hutt: Institute of Geological & Nuclear Sciences Institute of Geological & Nuclear Sciences science report 93/19 133 p.
Abstract: This report reviews the biostratigraphies of 13 selected petroleum exploration drillholes located from southern Hawkes Bay to East Cape on th East Coast of North Island, a total distance of about 300 kilometres. The wells were drilled over a span of 48 years from 1938 to 1986. The wells reviewed are Takapau-1, Ongaonga-1, Mason Ridge-1, Taradale-1, Hawke Bay-1, Opoutama-1, Mangaone-1, Ruakituri-1, Totangi-1, Rere-1, Waitangi Station-1, Te Puia-1, and Te Horo-1. These wells display the considerable variety of strata and structure to be found on the East Coast. Rocks penetrated range in age from Wanganui to Clarence series (Pleistocene to mid-Cretaceous); two of the wells reached Torlesse basement (Triassic-Jurassic). Structure encountered ranges from simple, straightforwerd sequences (e.g. Mason Ridge, Taradale) to complex or chaotic (e.g. Opoutama, Te Horo). The foraminiferal biostratigraphy is revised where possible within the framework of the New Zealand Series and Stage system, within the limits of the material present and within the scope of the study. In many cases opportunities exist for further revision and refinement. Provisional paleoenvironmental analysis are also presented, as based on available faunal slides and species lists. These could also be significantly improved with repicking of existing or rewashed material. (auth)