Landscape history of the Marlborough Sounds, New Zealand Journal Paper
- Author
- Nicol, A.
- Year
- 2011
- Journal / Source
- New Zealand Journal of Geology and Geophysics
- Volume
- 54
- Pages
- 195-208
- Keywords
- drowned valleys; eustatic sea-level changes; Marlborough Sounds; ria; subsidence; Wanganui Basin
- Summary
- Late Quaternary dune sand formations in the sand country areas near Aotea and Kawhia Harbours are described and discussed. Kaihu Group sediments are noted, and three new members of eolian sand are named and defined. These are: the Te Akeake Sands Member of the Waiau B Formation, deposited between c, 83 000 years and c. 42 000 years ago; the Paparoa Sands Member of the Mitiwai Sands Formation deposited about 2000 years B.P.; and the Nukumiti Sands Member, also of the Mitiwai Sands Formation, deposited between the time of first Maori occupation of the area, c. 800 years B.P., and the present. The Te Akeake Sands Mernber was deposited during aperiod when a lower sea level exposed a ready source of sand. The cause of dune building is not known for the Paparoa Sands Member; however, deposition of the Nukumiti Sands Member was initiated by disturbance of the Paparoa Sands Mernber by Maori agriculture. Geomorphic features of the three members include dune lakes impounded by the Te Akeake Sands Member, cliff-top dunes, both relict and actively developing, and parabolic dune forrns. The latter are interpreted as the later stages of dune field deve1opment, when the sand was already partially stahilised, Orientation of the paraholic dunes indicates that the resultant direction of sandmoving winds was from the south-west during the deposition of all three eolian sand members.