Sedimentology and evolution of Ohiwa Harbour, a barrier-impounded estuarine lagoon in Bay of Plenty Journal Paper
- Author
- Richmond, B.M.; Nelson, C.S.; Healy, T.R.
- Year
- 1984
- Journal / Source
- New Zealand Journal of Marine and Freshwater Research
- Volume
- 18
- Pages
- 461-478
- Keywords
- Quatemary, Pleistocene, Holocene, Kaihu Group, North Kaipara Barrier, Hautawan, Okehuan, palynology, terraces, stratigraphy, sea levels, South Head Formation, Shelly Beach Formation, new stratigraphie names, Dargaville Formation, Rototuna Formation, Pareotaunga Formation
- Summary
- North Kaipara Barrier is formed by sediments, mainly estuarine and dune sands of the Kaihu Group, deposited in a major cyc1e of transgression (subsidence) and regression (uplift) during the Quatemary. Hautawan, Okehuan and younger lignites along with terrace surfaces at 105 m, 67 m, 40 m, 24 m, 8 m and 4-2 m a.s.l., which can be correlated with dated surfaces elsewhere in the North Island, provide chronologie contro!. Five units, the Hautawan DargaviIle Formation, Nukumaruan-Castlec1iffian Rototuna Formation, Castlec1iffian-Hawera Pareotaunga Formation, Hawera South Head Formation, and the Hawera Shelly Beach Formation, are present. The barrier has changed littie since the end ofOkehuan time when the major existing valleys were cut in Rototuna sediments. Upper Pleistocene terrace surfaces are locally preserved within these valleys. Undifferentiated Hawera and Holocene deposits are also present on the barrier.