An investigation into the use of pollen from South Mavora Lake for paleoclimate reconstruction
The proxies embedded within both lake and peat bog sediments provide information on both vegetation and by inference climate changes. When developing paleoclimate records based on pollen, peat bogs are favoured due to passive modes of accumulation and simple proxy source models. However, slow accumulation rates result in low resolutions and poor recording of decadal to centennial scale environmental changes. Lacustrine systems offer higher resolution records, robust chronologies, and multiple supporting proxies. However, modes of accumulation are complex, and the role fluvial processes and lacustrine dynamics play in shaping paleoclimate records are currently poorly understood thus, lacustrine records are currently underutilised in pollen based paleoclimate research. Pollen taphonomy can indicate sediment sources and pre/post depositional processes. Therefore, not only can pollen be used to investigate climate, the role of catchment processes in shaping the final record can be determined. Parallel pollen-based paleoclimate reconstructions have been developed from an adjacent lake/peat bog complex at South Mavora. With the peat bog record acting as a control, pollen taphonomy has been used to investigate inputs into the lacustrine environment and a conceptual pollen input model for South Mavora lake has been constructed. Remobilised terrestrially stored pollen is the dominant pollen source in South Mavora Lake. However, given the similarities seen between the two Mavora records and that the trends seen in these records are seen at other sites, it can be concluded it is a suitable site for pollen reconstruction. Furthermore it can be concluded that lacustrine systems are suitable sources of pollen based paleoclimate information where the influence of catchment and lacustrine processes are carefully considered.
Advisor: Fitzsimons, Sean
Degree Name: Master of Science
Degree Discipline: School of Geography
Publisher: University of Otago
Keywords: New Zealand; lacustrine processes; paylnology; pollen; geomorphic; climate change
Research Type: Thesis