A reconstruction of Late Pleistocene to Holocene palaeoenvironmental change at Basin Lake, Fraser Island.

This item is only available electronically.Fraser Island lake sediments may record valuable information about past environmental changes, which in turn may provide key insights into the mechanisms driving this variability. This information is vital if we are to determine how the Fraser Island environment has reacted to climate changes in the past, and by extension, how it may react to similar conditions in the future. In this study, the geochemical composition of sediments from Basin Lake, Fraser Island, were characterised using a combination of organic and moisture content analyses, micro-XRF analysis, traditional XRF analysis, X-ray diffraction, particle size analysis and radiocarbon dating. The Basin Lake sediments contain a mixture of locally derived sand and far travelled dust, in proportions that have varied through time. Changing environmental conditions resulted in the deposition of four distinct sediment units within the lake. The new data presented here indicates that regional scale aridity was a dominant influence on sediment deposition on Fraser Island at or before 49 thousand years before present, resulting in a high percentage of distally sourced sediment in Basin Lake. During the Last Glacial Maximum, extreme local aridity resulted in increased contribution from locally-derived sediment before a return to wetter conditions during the early Holocene. The Late Holocene sediments preserve evidence for greater climate variability, alternating between arid and wet environments.Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 201