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Thesis (Ph.D.) -- University of Melbourne, School of Earth Sciences, 2005. / Typescript. Includes bibliographical references (leaves 239-266).

Thesis (M.S.) in Ecology and Environmental Science--University of Maine, 2004. / Includes vita. Includes bibliographical references (leaves 34-38).

Stratigraphic studies of layers of volcanic ash, or tephra, in buried soils have been used to date accurately Holocene glacier fluctuations in Southern Iceland. 132 stratigraphic sections up to 11m deep, and containing up to 78 tephra layers, were logged to a resolution of 0.25cm. The chronological framework was completed with 12 radiocarbon dates, and by examing the association of the tephra stratigraphy with moraines representing former ice margins, a chronology of Holocene glacier fluctuations was constructed. The forelands of five glaciers were studied: Seljavallajokull, Gigjokull and Steinholtsjokull (outlets of Eyjafjallajokull) and Solheimajokull and Klifurarjokull (outlets of Myrdalsjokull). This study has shown for the first time that large glaciers existed in mid-Holocene Iceland because after 700 BP and before 4500 BP Solheimajokull extended at least 4km beyond its present limits, and terminated at less than 100m above sea level. Other major advances of this glacier culminated before 3100 BP, and between 1400-1200 BP. In the tenth century AD Solheimajokull was also longer than during the late Little Ice Age (1700-1900 AD). In contrast, Klifurarjokull and all the outlets of Eyjafjallajokull reached a maximum Holocene extent during the late Little Ice Age. It is proposed that the anomalous behaviour of Solheimajokull may be explained as a result of catchment changes caused by the growth of the Myrdalsjokull ice cap. The great human impact on the landscape since the Norse Settlement (c870-930 AD) has also been assessed as a result of the extensive study of the aeolian sediments lying between numerous, accurately dated tephra layers. These studies show that a zone of chronic soil erosion developed in the natural upland pastures immediately after the Norse Settlement and slowly swept down hill to reach lowlying areas during the last 400 years.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 99-111).

The global climate has experienced four glacial cycles in the last 420,000 years, with each cycle characterised by a prolonged period of cooling culminating in maximal glaciation followed by a brief warm period. The most recent period of maximal glaciation is termed the Last Glacial Maximum (LGM) and occurred about 21,000 years ago. We currently live in one of the warm periods. The global climate is changing, and it is becoming more important to understand the extremes of the climate system and how well our modelling capability can capture those extremes. / There has been a modelling intercomparison project established to examine how global general circulation models compare in simulating past climates, including the LGM. Analysis and comparison of these model results has been presented for many parts of the globe, but there has not been a comparison of the different model results over the Australian region. This thesis aims to fill that gap and explore the simulated LGM weather and climate of Australia and its drivers in more detail. Comparison with proxy evidence is also undertaken, and inconsistencies seen in the literature addressed. / The Australian climate at the LGM was believed to be generally cooler, drier and possibly windier from proxy evidence in the literature. In the comparison done here the mean temperature and precipitation fields from most models show cooler and drier conditions, with some seasonal variability, but there are some strong outliers. It was found that the differences were not dependent on model resolution, but that the surface parameterisations were highly important for these fields. / The shifts in the circulation were examined both in the model results and with a study of the non-linear link between the wind, surface moisture and dunes, which are a proxy for past winds. All the models simulate a southward shift in the westerlies in the Australian region. This is strongly driven byte prescribed sea-surface temperatures. Australia's current wind regime is conducive to dune building. However, the binding effect of soil moisture (or vegetation) is strong enough to limit present day movement, whereas in the drier climate at the LGM there was a capacity for sand movement. The analysis of dune orientations did not produce conclusive evidence for how the westerlies might have shifted at the LGM. / An apparent enigma in the proxy evidence at the LGM is the high lake levels in Australia’s south east, while most inland lakes were dry. Previous authors believed that the precipitation was still low, but the high lake levels were driven by lowered potential evaporation. The hydrological cycle was generally depressed in the LGM simulations, but the potential for evaporation remained high. Thus an alternative hypothesis is posed based on increased run off due to a known shift in the vegetation types and a lag in the timing of the run off due to snowmelt. / The analysis here shows that our capacity to simulate climates quite different from the present is still developing, but that model results can help explain apparent inconsistencies in the reconstruction of past climates from proxies.

Thesis (Ph. D.)--Texas State University-San Marcos, 2007. / Vita. Appendices: leaves 178-213. Includes bibliographical references (leaves 214-234).

Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). One map in pocket. Includes bibliographical references (leaves 131-145). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 186-196).

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