Full Download The Last Glacial Maximum and Deglaciation in Southern New Zealand: New Pollen-Climate Reconstructions - Newnham, Rewi; Vandergoes, Marcus; Callard, Sarah Louise file in ePub Online

Victoria University of Wellington 2011 Genre/Form: DoctoralText Material Type: Internet resource Document Type: Internet Resource, Archival Material All Authors / Contributors: Newnham, Rewi; Vandergoes, Marcus; Callard, Sarah Louise OCLC Number: 778929589 Language Note: en_NZ Abstract: The project builds upon existing knowledge of late Quaternary palaeoenvironmenta change and tests the recently developed New Zealand INTIMATE (Integration of Ice Marine and Terrestrial archive) climate event stratigraphy (NZ-I CES; 30-8 ka). Four pollen and sediment records from three climatically contrasting regions in the South Island provide a vegetation and climate history for this area between 38-4 ka. In this study, the Last Glacial Cold Period (LGCP; c. 31.4-18.9 ka) is characterised by a two step cooling, with the coldest conditions, reaching possibly 5.3°C cooling, occurring between 21-19 ka, marking the Last Glacial Maximum. A new precipitation proxy using macrophyte pollen concentrations at an eastern South Island site suggests dominantly dry conditions prevailed during the LGCP except for two periods of wetter climate around 26-24 ka and 21 ka. The dry periods correspond with evidence of glacial advance, colder environments and possibly increased intensity of the southern westerlies. Conversely, the wet periods coincide with reduced glacial activity, milder climates and decreased westerly wind intensity. Deglaciation began between 18.9-18.4 ka followed by rapid climate amelioration culminating with Dacrydium cuppressinum-dominant lowland forest at western sites as early as 11.9 ka, indicative of the start of the Holocene. A disturbance in forest development occurs between 13.4-11.9 ka in one record and may be indicative of a minor cooling within the timeframe of a late glacial climate reversal recognised in the NZI-CES. Overall the project results (timing and pattern of climate change) broadly align with the NZ-I CES. However, there are some disparities, in particular during the LGCP, which this study suggests began at least 3-4 ka earlier than concluded in the NZ-I CES. The NZ-I CES oversimplifies the complexity of the LGCP which contains evidence of significant climate variability that may be important for an understanding of the possible forcing fact