| Summary: | Graduate Holocene climate variability in the British Columbia Coast Mountains has resulted in repeated intervals of glacier expansion and retreat. Since reaching their late Holocene maximum positions in the late 20th century, glaciers in the region have experienced significant volumetric loss. The subsequent downwasting and frontal retreat has revealed forests buried by glacier advances throughout the Holocene, enabling description of significant intervals of ice expansion using dendroglaciology. This thesis characterizes dendroglaciological evidence as it relates to climate at two scales: (1) at Franklin Glacier in the Mt. Waddington area, and; (2) throughout the Coast Mountains. Dendroglaciological evidence from glacier forefields and lateral moraines in the Coast Mountains provides evidence for at least 11 intervals of glacier activity during the Holocene. The earliest record glacier activity is documented in the Pacific Ranges from 8.5 to 7.8 ka, after which glaciers in this region retreated during the early Holocene warm and dry interval. Following this a glacial advance from 6.7 to 5.6 ka was followed by a subsequent expansion episode from 5.1 to 4.6 ka in response to attendant cool and moist conditions in the Pacific Ranges. After 4.6 ka, glaciers in the Pacific and Boundary ranges advanced at 4.4 to 4.0 and 3.8 to 3.4 ka during intervals characterized wet conditions resulting from an intense, eastwardly positioned Aleutian Low pressure centre. Following 3.4 ka most glaciers retreated before expanded between 3.2 and 2.8 ka, retreated, and then advanced from 2.6 to 2.4 ka. Glacier advances from 1.8 to 1.1 ka occurred in response to a regional cooling event, and proceeded Little Ice Age advances from 0.6 to 0.4 ka. Franklin Glacier is an 18-km long valley glacier that originates below the west face of Mt. Waddington. Radiocarbon-dated wood samples from the proximal faces of lateral moraines flanking the glacier show that it expanded at least nine times since 13 ka. A probable Younger Dryas advance of ...
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