Late Holocene glacial history of Scimitar Glacier, Mt. Waddington area, British Columbia Coast Mountains, Canada by Jessica Aileen Craig B.Sc., University of Victoria, 2010 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE in the Department of Geography © Jessica Aileen Craig, 2012 University of Victoria All rights reserved. This thesis may not be reproduced in whole or in part, by photocopy or other means, without the permission of the author. ii Supervisory Committee Late Holocene glacial history of Scimitar Glacier, Mt. Waddington area, British Columbia Coast Mountains, Canada By Jessica Aileen Craig B.Sc. University of Victoria, 2009 Supervisory Committee Dr. Dan J. Smith, (Department of Geography) Supervisor Dr. John J. Clague (Department of Geography) Departmental Member iii Supervisory Committee Dr. Dan J. Smith, (Department of Geography) Supervisor Dr. John J. Clague (Department of Geography) Departmental Member 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. iv 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. v Table of Contents Supervisory Committee ...................................................................................................... ii Abstract .............................................................................................................................. iii Table of Contents .................................................................................................................v List of Tables ..................................................................................................................... vi List of Figures ................................................................................................................... vii Acknowledgements ............................................................................................................ ix Chapter 1 – Introduction ..................................................................................................1 1.1 Introduction ...............................................................................................................1 1.2 Research Purpose and Objectives .............................................................................2 1.3 Thesis Format............................................................................................................3 Chapter 2 – Study Area ....................................................................................................4 2.1 Introduction ................................................................................................................4 2.2 The Waddington Range .............................................................................................4 2.3 Previous Research .....................................................................................................7 2.4 Summary .................................................................................................................10 Chapter 3 – Scimitar Glacier ..........................................................................................12 Chapter 4 – Research Methods ......................................................................................14 4.1 Introduction .............................................................................................................14 4.2 Aerial Photographic Interpretation Methods ..........................................................14 4.3 Field Methods ..........................................................................................................15 4.4 Laboratory Preparation and Analysis .......................................................................15 Chapter 5 – Observations ................................................................................................17 5.1 Prior Exploration and Aerial Photograph Interpretation .........................................17 5.2 Living tree-ring chronologies .................................................................................26 5.3 Dendroglaciological samples ..................................................................................26 5.3.1 Site 1 - Umbra Mountain .................................................................................27 5.3.2 Site 2 – Radiant Falls .......................................................................................31 5.3.3 Site 3 - Dispatch Lake ......................................................................................33 Stratigraphic interpretation ...................................................................................48 Chapter 6 – Discussion ....................................................................................................50 6. 1 Introduction ............................................................................................................50 6.2 Dating and Interpretation ........................................................................................50 Radiocarbon dating ...................................................................................................50 Tree-ring dating .........................................................................................................53 Interpretation .............................................................................................................54 6.3 Regional Synthesis ..................................................................................................56 Chapter 7 – Conclusions .................................................................................................58 7.1 Summary .................................................................................................................58 7.2 Limitations and Future Research ............................................................................59 vi List of Tables Table 5.1: Vertical and oblique aerial photographs of Scimitar Glacier, 1949-2005. .......22 Table 5.2: Chronology statistics for the locally derived living subalpine fir and whitebark pine chronologies. ..................................................................................................26 Table 5.3: Subfossil wood samples collected at three sites along the margins of Scimitar Glacier in July 2011. ..............................................................................................29 Table 6.1: Summary of radiocarbon-dated dendroglaciological evidence recovered along the margins of Scimitar Glacier at sites 1 and 3. ...................................................52 Table 6.2: Summary of tree-ring ages of samples recovered along the margins of Scimitar Glacier at sites 2 and 3. ..........................................................................................54 vii List of Figures Figure 1.1: View looking down Scimitar Glacier from Fury Gap. Photo by Phyllis Munday (Munday, 1928). ........................................................................................1 Figure 2.1: Map of the Scimitar Glacier study area showing study sites. ...........................5 Figure 2.2: Google Earth image of the Mt. Waddington Range area showing the locations of Confederation, Franklin, Tiedemann, Oval and Jambeau glaciers. Locations of living tree-ring width chronologies used in this study are also indicated. ..................................................................................................................8 Figure 5.1: Historical photo taken by Henry Hall Jr. showing the terminus of Scimitar Glacier as of 1931 (Hall, 1932). .............................................................................18 Figure 5.2: Illustration of lateral recession of Scimitar Glacier from Pocket Valley, 1949- 2005. The locations of the ice margin are derived from overlays of historical aerial photographs (A12973-171, NRCan; R60 26-F47,