Quaternary geology and stratigraphy of North Westland, South Island, New Zealand.
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Infrared stimulated luminescence ages are presented from the North Westland region, West Coast, South Island, New Zealand. These ages span much of the last interglacial-glacial cycle from 123.3 ± 12.7 ka to 33.6 ± 3.6 ka. Coverage is extended to c. 14 ka via cosmogenic isotope dating. A new Quaternary stratigraphy and Marine Isotope Stage correlation is proposed for the on-shore glacial-interglacial fluvioglacial, fluvial and marine terrace sequence. The new model incorporates previously published luminescence and radiocarbon ages. It necessitates reinterpretation of the evolution of the climate in North Westland for the period from 123 ka to 14 ka. Reinterpretation of fossil pollen and plant macrofossil records implies a period of probable near-interglacial climate in North Westland during the early to middle portion of Marine Isotope Stage 3. It also implies the presence in North Westland of raised marine terraces dating from this Isotope Stage. In addition it is concluded that during the period from c.60 ka to c.50 ka podocarp dominated forest was widespread in the lowland portion of Westland. Between Okarito and Westport Dacrydium cupressinum and Nestegis were ubiquitous components of this forest. This finding aligns the Marine Isotope Stage 3 climate of North Westland nicely with that of other parts of New Zealand where good records exist for this period.