Late Holocene glacial history of Scimitar Glacier, Mt. Waddington area, British Columbia Coast Mountains, Canada

Date

2012-12-21

Authors

Craig, Jessica Aileen

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Abstract

Scimitar Glacier originates below the northeast face of Mt. Waddington in the southern British Columbia Coast Mountains and flows 18 km down valley to calve into a proglacial lake. The purpose of this research was to describe the late Holocene glacier history of Scimitar Glacier using stratigraphic analysis in conjunction with dendroglaciologic and radiocarbon dating techniques. Downwasting of the glacier surface has exposed stacked till units separated by wood-bearing horizons in the proximal slopes of lateral moraines flanking the glacier at several locations. Historical moraine collapse and erosional breaching has also revealed the remains of standing trees buried in sediments from a lake originally ponded against the distal moraine slope. Radiocarbon dating of detrital wood remains revealed that Scimitar Glacier expanded down-valley at least three times in the late Holocene. The earliest period of expansion occurred 3167-2737 cal yr BP in association with the regional Tiedemann Advance. Following this the glacier receded and downwasted prior to advancing to reconstruct the lateral moraine in 1568-1412 cal yr BP during the First Millennial Advance. The most recent phase of moraine construction was initiated during late Little Ice Age glacial expansion before 1742 AD and extended until at least 1851 AD, after which Scimitar Glacier began to recede and downwaste. Field investigations at Scimitar Glacier allowed for the construction of a late Holocene history of glacier expansion and lateral moraine construction that spans the last 3000 years. This record is comparable to that recorded at other glaciers in this region, and confirms the long-term relationship between regional climate trends and glacier behaviour in this setting.

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Keywords

Coast Mountains, Dendrochronology, Dendroglaciology, moraine dammed lake, Holocene, Waddington Range

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