| Summary: | This thesis investigates the 'Little Ice Age' (LIA) glacial maximum in southeast Iceland through integration of the glaciological, climatological and historical records of change in order to enhance current understanding about the timing, expression and consequences of glacier-climate interactions. Previous opinions have differed regarding the timing of the LIA maximum extension of Icelandic glaciers with possibilities generally ranging from the mid-/late- 18th to late 19th centuries. Moraines along the margins of Skalafellsjokull and Heinabergsjokull, two Vatnajokull outlet glaciers in southeast Iceland, were dated in order to examine whether disparities may have arisen due to differing glacier response rates, selective preservation of evidence or unreliable dating techniques. Approximately 12,000 lichens were measured on 40 moraine fragments to provide surface age proxies. The population gradient lichenometric technique yields late 18th to early 19th century moraine dates, whereas the conventional 'average of the five largest' method clusters moraine dates to the late 19th century. Subsequently, an updated tephrochronology for southeast Iceland (based on geochemistry and tephrastratigraphy) obtained from 25 reference soil profiles was used to identify tephra layers within 15 additional soil profiles dug around the LIA moraines. Tephrochronology is consistent with the LIA maximum extent for both glaciers occurred between AD 1755 and 1873. A late 18th to early 19th century LIA maximum at Skalafellsjokull and Heinabergsjokull accords with widespread glacial maxima across Iceland, indicative of a pervasive response to climatic deterioration. A positive degree-day mass balance model was implemented for Skalafellsjokull, Heinabergsjokull and Lambatungnajokull to assess the linkages between spatial expression of LIA glacier maxima with potential climatic envelopes during the late 18th to early 19th centuries. Reconstructions suggest that LIA maximum glacier mass balance was induced by a ~1-1.5°C temperature ...
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