PHYTOLITH RECONSTRUCTION OF THE ENVIRONMENT SURROUNDING THE KAWAKAWA TEPHRA IN BANKS PENINSULA, SOUTH ISLAND

The use of phytoliths in paleoenvironmental reconstructive research is well documented in New Zealand with a wide variety of identification resources available. This in combination with their high preservation potential, in situ deposition, and distinctive morphologies, makes phytoliths ideal for reconstructing prehistoric vegetation patterns and inferring paleoenvironmental conditions at Pa Bay, Banks Peninsula. An extensive methodology was developed, drawing from multiple sources, and the resulting samples were counted and compared to known paleoenvironmental data, aided temporally by the presence of the chronostratigraphic Kawakawa tephra horizon deposited ~25.4 ka. The results gave an idea of the environment during the last glacial maximum, although it showed little change over time. The most common phytoliths were grass morphologies, particularly elongate columns that indicate cold-weather grasses. The grass morphologies in addition to the occasional spherical morphology indicative of a tree or shrub imply a moderate to cold grassland with sparse coverage. Additionally, the tentative identification of the diatom Cyclostephanos novazeelandiae confirms the identity of the Kawakawa tephra. More experience with phytolith identification is needed for more accurate results in future research.