Late holocene climate variability In the Australian Alps: can sedimentary and geochemical tracers track fine scale paleo-environment change?
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Date
2018-12-10
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Publisher
Australasian Quaternary Association Inc.
Abstract
The Australian Alps have experienced some of the most dramatic change in any Australian landscape over the last glacial cycle, i.e. shifting between cold-climate conditions, glacial growth and dominance of periglacial processes and present day (warm) conditions. While these large scale changes are well documented, less is known about how the Alps have responded to more minor palaeo-climate change during the Holocene. Minor temperature changes may result in a measurable landscape response because they would be expected to manifest in changes to the occurrence of cold-climate processes, such as freeze thaw or solifluction, or conversely, increased vegetation cover and landscape stability. Sedimentary records from cirque lakes, therefore offer the potential to examine palaeo-environmental change in the alpine region during the late Holocene. In this study we examine recent (late Holocene) changes in the Alpine region of Kosciuszko National Park using cores extracted from Blue Lake and Club Lake. The two short cores date from 3,500 and 1,900 cal. yr BP, respectively. At Blue Lake, there is relatively little change recorded over most length of the core with the exception of a minor period of changing sedimentation rates and increased charcoal at 2,200-2,800 cal. yr BP, implying possible increased fires and associated landscape instability.
Similarly, the Club Lake core also records little variability, although a change in sediment geochemistry implies the addition of less weathered material to the lake during the Little Ice Age, implying a potential increase in physical weathering. The most substantial change in both cores occurred within the last 200 years, with the addition of finer, less organic and significantly more chemically weathered material to the lakes. This coincides with the onset of grazing in the alpine region. This change implies that there has been increase in the contribution of sediment derived from soil to the lakes and, in particular, an increased contribution from subsoil (which in the case of the Australian Alps are more weathered). Finally, there is evidence of recovery in the top few centimetres of the cores implying conditions in the Alps have recovered from the dramatic grazing era perturbation, with conditions now similar to those over most of the late Holocene. © Author(s)
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Keywords
Quaternary period, Climatic change, Australia, Alps, Glaciers, Environment, Geochemistry, Geology, Plants, Sedimentation, Fires
Citation
Stromose, N., Vernon, J., Marx, S., Woodward, C., & Saunders, K. (2018). Late holocene climate variability In the Australian Alps: can sedimentary and geochemical tracers track fine scale paleo-environment change? Paper presented at the AQUA Biennial, Canberra, 10-14 December 2018, (pp. 106). https://aqua.org.au/wp-content/uploads/2019/10/AQUA-2018-Program.pdf