Jim Blaikie

PhD Research Student

BSc Environmental Science and Outdoor Education (1st class Hons), University of Stirling, 2012

Supervisors: Dr Robert McCulloch  Dr Eileen Tisdall

Start Date: 1st October 2012

3A124A, Cottrell Building
Biological & Environmental Sciences
Faculty of Natural Sciences
University of Stirling
Stirling, Scotland, FK9 4LA

tel: +44 (0)1786 467
fax: +(44) 1786 467843
email: James Blaikie

Research Project

Palaeoecological reconstruction of rapid Late Glacial - Holocene environmental change for Central Patagonia, southern South America

This project will provide a high-resolution record of climatic and environmental change for the southern hemisphere region of Patagonia in the vicinity of the North Patagonian Icefield (~47°S) .The palaeoclimatic history of southern South America (also known as Patagonia), is dominated by the strength and latitudinal position of the Southern Westerly storm tracks (presently centred on ~50°S). Patagonia lies along this zone of high precipitation and past migrations of these storm tracks can be tracked through fluctuations of the Patagonian ice fields and the response of the surrounding vegetation cover (McCulloch & Davies, 2001). These dramatic palaeoenvironmental changes are the backdrop for the early peopling of southern South America as the first humans migrated southwards following the Andean mountains. Our current understanding of southern hemisphere ocean-atmosphere changes in the Late Quaternary is largely derived from reconstructions of the glacier fluctuations during the Late Glaciation/Holocene transition (McCulloch et al., 2005) but this provides a limited view of the changing environment faced by the first hunter-gathers in the region.

To reconstruct the Late Glacial and Holocene environments this project will produce high-resolution (sub-centennial) records of vegetation change using pollen analysis (Palynology) from lake and peat site. Pollen analysis remains the most powerful technique for the reconstruction of past landscape change due to the spatial nature of the data and the temporal continuity in the records. Deep basin sediments (both lacustrine and peat) have been identified along an east-west transect between 48°S and 46°S to provide temporally high-resolution sediments. It is anticipated that the palaeovegetation records, focusing on the altitudinal and longitudinal shifts in ecotones, from the hyper-humid to semi-arid, will circumscribe the timing and extent of temperature changes during the Late Glacial/Holocene transition and shifting focus of precipitation during the Holocene at sub-centennial scale. These records will be reinforced through lithostatigraphic analyses (organic content, peat humification and geochemistry) and constrain in time using radiocarbon dating (supported by the Scottish Universities Environmental Research Centre) and tephrochronology (dating using volcanic ash layers)(supported by the NERC tephra unit, University of Edinburgh).

The resulting palaeoecological records will be able to explore the following themes:

There is clear overlap between these themes and they will combine to form a regional synthesis from which we will be able to infer the timing and nature of southern hemispheric climatic fluctuations and their impacts on vegetation resources of southern Patagonia. This research will provide valuable empirical data with which the science and policy communities can assess the extent to which future climate changes in the context of a carbon dioxide enriched atmosphere will impact on present vegetation and resource patterns of Patagonia.

This research project will be carried out with the support from the Instituto de ArqueologÍa, Facultad de FilosfÍa y Letras, Universidad de Buenos Aires, Buenos Aires, Argentina and the Centro de los estudias de los hombres, Universidad de Magallanes, Punta Arenas, Chile.

References

McCulloch, R. D. and Davies, S. J. (2001) Late-Glacial and Holocene palaeoenvironmental change in the central Strait of Magellan, southern Patagonia.Palaeogeography, Palaeoclimatology, Palaeoecology173, 143-173.

McCulloch, R. D., Fogwill, C. J., Sugden, D. E., Bentley, M. J. and Kubik, P. W. (2005) Chronology of the last glaciation in central Strait of Magellan and BahÍa Inútil, southernmost South America. Geografiska Annaler87A(2) 289-312.

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