Browsing by Author "O'Brien, Regan William"

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    Quaternary vegetational, environmental and climatic history of the lower Taieri Plain, East Otago, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Quaternary Science at Massey University
    (Massey University, 2000) O'Brien, Regan William
    This project presents the palynology of the 154m Waipori 99-1 long core taken from the Lower Taieri Plain, east Otago, New Zealand. The current vegetation and climate are reviewed along with the geological and geomorphological setting of the Taieri Basin. Reviews are given on the history of New Zealand's vegetation since the Late Cretaceous and on the late Pleistocene and Holocene vegetation and climate of southern New Zealand. The field and lab techniques used in the course of this project are detailed. The Waipori 99-1 long core contained a number of extensive glacial aggradational gravel sequences. These are separated in places by interbedded fine sediments which were found, for the most part, to have been deposited during warm climate periods. Subsidence within the basin has determined which sediments survive in the record. Periodic subsidence and fluvial erosion have resulted in a discontinuous sedimentary sequence. Polliniferous sediments were found only above -103m. Pollen analysis suggests that the sediments may date back as far as the mid Quaternary. Dating on the core poorly constrains sediments which pre-date the Holocene. The pollen evidence presented in this project is used to create a number of possible chronological lines along which to interpret environmental information derived from the core. No particular line is fully endorsed by the project however. As many as four, and possibly five, warm climate pollen assemblages are recognised. Pollen analysis suggests that during these warm periods, podocarp-broadleaf forests occupied the basin. Prumnopitys taxifolia was the most consistently common podocarp in the region. Fuscospora beeches appear to have once been more common in the area in contrast to the present day. Dacrydium cupressinum was apparently absent from the area during the mid to late Quaternary, expanding into the basin only in the mid Holocene. The Holocene vegetational, climatic and environmental record is in agreement with others published from southern New Zealand.