DOCSLIB.ORG

Geomorphology of Vancouver Island: Mass Wasting Potential I © 2005 Province of British Columbia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geomorphology of Vancouver Island: Mass Wasting Potential I © 2005 Province of British Columbia Geomorphology of Vancouver Island: Mass Wasting Potential Victoria, British Columbia Research Report No. RR 01 December 2005 by RH Guthrie Regional Geomorphologist Geomorphology of Vancouver Island: Mass Wasting Potential i © 2005 Province of British Columbia Library and Archives Canada Cataloguing in Publication Data Guthrie, R. H. (Richard Hamilton), 1969- Geomorphology of Vancouver Island [electronic resource]: mass wasting potential. Includes bibliographical references: p. Available on the Internet. ISBN 0-7726-5468-9 1. Geomorphology - British Columbia – Vancouver Island. 2. Mass-wasting – British Columbia – Vancouver Island. I. British Columbia. Ministry of Environment. II. Title. GB428.5.C3G87 2005 551.41’09711’2 C2005-960251-1 Citation Guthrie, R.H. 2005. Geomorphology of Vancouver Island [electronic resource]: mass wasting potential. B.C. Ministry of Environment, Victoria, BC. Research Report No. RR01. Copies of this report are available online through B.C. Ministry of Environment at http://wlapwww.gov.bc.ca/wld/pub/pub.htm Disclaimer: Interpretation of the results and analysis are solely those of the author and do not represent the opinions of the Ministry of Environment or the Government of British Columbia. ii Geomorphology of Vancouver Island: Mass Wasting Potential Geomorphology of Vancouver Island: Mass Wasting Potential iii ACKNOWLEDGEMENTS The assistance of Charles Penner in creating the initial map is gratefully acknowledged. I am also grateful to Stuart Atkins who provided substantial air photograph interpretation from which most of the analyses are derived, and to Catherine Shilston who worked on analysis and organization of the many datasets that resulted from the air photograph interpretations. Ross Petit and Shari Lindsay provided substantial GIS and cartographic support to the project. Gail Harcombe of the Ministry of Environment provided or arranged editorial review. Finally, I’m grateful to Steve Evans of the University of Waterloo and Oldrich Hungr of the University of British Columbia for providing technical reviews of the manuscript. ii Geomorphology of Vancouver Island: Mass Wasting Potential Geomorphology of Vancouver Island: Mass Wasting Potential iii ABSTRACT The Geomorphology of Vancouver Island is a series of nine thematic maps, one of which is a map of mass wasting potential for Vancouver Island. This report represents a description of the Mass Wasting Potential Map and the results of analyzing the regional character of landslide potential. Vancouver Island has been divided into four major zones: the Wet West Coast, Moderately Wet Central Island, Moderately Dry East Coast, and Alpine (zones I–IV, respectively). Landslide frequencies are proposed at 0.012, 0.007, and 0.004 events per square kilometre per year for zones I–III respectively, and several times higher for zone IV. Mass movements in zones I–III are generally dominated by debris slides and debris flows averaging about 11,000 2m , but ranging nearly three orders of magnitude. The Alpine Zone (Zone IV) contains substantial areas of rock fall and snow avalanches in addition to debris slides and flows. Two sub-zones related to bedrock geology were established because of associated differences in landslide behaviour: the Island Plutonic Suite appears to be more stable under natural (typically unfractured and unweathered) conditions, but is less stable under conditions that alter the rock (e.g., road building and frost shattering), and the Sicker Group is generally less stable than adjacent bedrock types. Other geological considerations were also incorporated into the map. The impact of logging and road building on landslide frequency is considered. Results indicate that logging activities increase landslide frequencies by more than 10 times, and the presence of roads increases landslide area by 22 to 43 times. These results corroborate previous studies. iv Geomorphology of Vancouver Island: Mass Wasting Potential Geomorphology of Vancouver Island: Mass Wasting Potential v TABLE OF CONTENTS Introduction and Background................................................................................... 1 Methods .................................................................................................................... 2 Definitions .......................................................................................................... 3 Debris slides and debris flows ....................................................................... 3 Rock falls and talus slopes ............................................................................. 5 Snow avalanches............................................................................................ 6 Cautions: Scale and Regional Variability ............................................................ 6 Results and Discussion.............................................................................................. 7 General Results ................................................................................................... 7 Mass Wasting Potential Map Zones .................................................................... 8 Wet West Coast (Zone I) ............................................................................. 9 Moderately Wet Central Island (Zone II) ..................................................... 9 Moderately Dry East Coast (Zone III) ........................................................ 10 Alpine (Zone IV) ........................................................................................ 10 Frequency Distribution .................................................................................... 10 Landslides and Geology on Vancouver Island.................................................... 12 Sub-zone b: The Island Plutonic Suite ........................................................ 13 Sub-zone c: The Sicker Group .................................................................... 16 Other potential sub-zones and bedrock considerations................................ 16 The influence of surficial geology on landslide rates .................................... 16 The Influence of Logging on Landslide Rates .................................................... 17 The Influence of Road Building on Landslide Rates .......................................... 18 Conclusions............................................................................................................. 19 References................................................................................................................ 20 Appendix I............................................................................................................... 22 List of Tables Table 1. Velocities of typical coastal landslide movement types (landslide data from Cruden and Varnes 1996) ................................................................................. 3 Table 2. Size and area of landslides from 35 randomly selected sites over 200 km2 of terrain on Vancouver Island ................................................................................... 8 Table 3. The number of landslides in each zone......................................................... 9 Table 4. Density and frequency of natural landslides by zone for Vancouver Island ....................................................................................................................... 10 iv Geomorphology of Vancouver Island: Mass Wasting Potential Geomorphology of Vancouver Island: Mass Wasting Potential v Table 5. Watershed-based landslide frequencies for Vancouver Island mass wasting zones compared with frequencies from previous watershed-based studies ................. 12 Table 6. Previous research showing landslide frequency relative to bedrock geology..................................................................................................................... 14 Table 7. Natural landslide frequencies for zones I-III for the dominant bedrock formations on Vancouver Island............................................................................... 15 Table 8. Logging-related landslide frequencies (including roads) for all zones for the dominant bedrock formations on Vancouver Island ........................................... 15 Table 9. Natural landslides (debris slides and flows) in the Alpine Zone on Vancouver Island ..................................................................................................... 15 Table 10. The impact of logging on density and frequency of landslides in this study ........................................................................................................................ 18 Table 11. The relative contribution of roads to landslide frequencies on Vancouver Island in this study ................................................................................................... 18 List of Figures Figure 1. The physiographic regions of Vancouver Island........................................... 2 Figure 2. Schematic representing the gathering of data for a mass wasting potential map for Vancouver Island, British Columbia ............................................................. 3 Figure 3. Stereo air photograph of a debris slide into a river on Vancouver Island ..... 4 Figure 4. Photograph of a debris slide from a road on Vancouver Island ................... 4 Figure 5. A stereo air photograph of a channelized debris flow on Vancouver Island .. 4 Figure 6. A stereo air photograph of a rock fall on Vancouver Island.........................
Load more

Recommended publications
  • Sturzstroms) Generated by Rockfalls
    Catastrophic Debris Streams (Sturzstroms) Generated by Rockfalls KENNETH J. HSU Geological Institute, Swiss Federal Institute of Technology, Zurich, Switzerland ABSTRACT sturzstrom. Key words: sturzstrom, debris I was fascinated by Heim's accounts and streams, rockfalls, landslides. chose the topic "Sturzstrom" as a theme of Large rockfalls commonly generate my inaugural speech in 1967 after my ap- fast-moving streams of debris that have INTRODUCTION pointment to Zurich. A theoretical analysis been called "sturzstroms." The geometry of and some preliminary experiments pro- sturzstrom deposits is similar to that of Large masses of rocks crashing down a duced evidence in support of Heim's claim mudflows, lava flows, and glaciers. steep slope commonly generate a stream of that the broken debris of large masses of Sturzstroms can move along a flat course broken debris, which often moves at fantas- rock flowed, but exchanges of written for unexpectedly large distances and may tic speeds over very gentle slopes for unex- communications failed to dissuade my surge upward by the power of their pectedly long distances. The famous Elm friend Ron Shreve from his conviction. momentum. A currently popular hypothesis rockfall of Switzerland, 1881, produced Furthermore, the necessary experimenta- to account for their excessive distance of such a debris stream; it buried a village and tion to deliver a decisive argument was transport suggests that sturzstroms slide on killed 115 persons. Albert Heim (in Buss never carried out, as my interests drifted air cushions. Contrary to that hypothesis, and Heim, 1881, p. 143) stated shortly elsewhere. Eventually the old manuscript evidence is herein presented to support after the catastrophe that he had never was taken out and dusted off when I Heim's contention that sturzstroms indeed known of such an example.
    [Show full text]
  • British Columbia Regional Guide Cat
    National Marine Weather Guide British Columbia Regional Guide Cat. No. En56-240/3-2015E-PDF 978-1-100-25953-6 Terms of Usage Information contained in this publication or product may be reproduced, in part or in whole, and by any means, for personal or public non-commercial purposes, without charge or further permission, unless otherwise specified. You are asked to: • Exercise due diligence in ensuring the accuracy of the materials reproduced; • Indicate both the complete title of the materials reproduced, as well as the author organization; and • Indicate that the reproduction is a copy of an official work that is published by the Government of Canada and that the reproduction has not been produced in affiliation with or with the endorsement of the Government of Canada. Commercial reproduction and distribution is prohibited except with written permission from the author. For more information, please contact Environment Canada’s Inquiry Centre at 1-800-668-6767 (in Canada only) or 819-997-2800 or email to [email protected]. Disclaimer: Her Majesty is not responsible for the accuracy or completeness of the information contained in the reproduced material. Her Majesty shall at all times be indemnified and held harmless against any and all claims whatsoever arising out of negligence or other fault in the use of the information contained in this publication or product. Photo credits Cover Left: Chris Gibbons Cover Center: Chris Gibbons Cover Right: Ed Goski Page I: Ed Goski Page II: top left - Chris Gibbons, top right - Matt MacDonald, bottom - André Besson Page VI: Chris Gibbons Page 1: Chris Gibbons Page 5: Lisa West Page 8: Matt MacDonald Page 13: André Besson Page 15: Chris Gibbons Page 42: Lisa West Page 49: Chris Gibbons Page 119: Lisa West Page 138: Matt MacDonald Page 142: Matt MacDonald Acknowledgments Without the works of Owen Lange, this chapter would not have been possible.
    [Show full text]
  • Characterization and Analysis of a Large Rockfall Along the Rio Chama, Archuleta County, Colorado
    CHARACTERIZATION AND ANALYSIS OF A LARGE ROCKFALL ALONG THE RIO CHAMA, ARCHULETA COUNTY, COLORADO by Robert L. Duran A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Masters of Science (Geological Engineering). Golden, Colorado Date_______ Signed_______________________ Robert L Duran Signed_______________________ Dr. Wendy Zhou Thesis Advisor Signed_______________________ Dr. Paul Santi Thesis Advisor Golden, Colorado Date_______ Signed_______________________ Dr. M Stephen Enders Professor and Interim Head Department of Geology and Geological Engineering ! ii! TABLE OF CONTENTS ABSTRACT ....................................................................................................................... vi LIST OF FIGURES .......................................................................................................... vii LIST OF TABLES .............................................................................................................. x ACKNOWLEDGMENTS ................................................................................................. xi CHAPTER 1: INTRODUCTION ....................................................................................... 1 1.1 Background ............................................................................................................... 3 1.2 Geologic Setting .......................................................................................................
    [Show full text]
  • Southern Exposures
    Searching for the Pliocene: Southern Exposures Robert E. Reynolds, editor California State University Desert Studies Center The 2012 Desert Research Symposium April 2012 Table of contents Searching for the Pliocene: Field trip guide to the southern exposures Field trip day 1 ���������������������������������������������������������������������������������������������������������������������������������������������� 5 Robert E. Reynolds, editor Field trip day 2 �������������������������������������������������������������������������������������������������������������������������������������������� 19 George T. Jefferson, David Lynch, L. K. Murray, and R. E. Reynolds Basin thickness variations at the junction of the Eastern California Shear Zone and the San Bernardino Mountains, California: how thick could the Pliocene section be? ��������������������������������������������������������������� 31 Victoria Langenheim, Tammy L. Surko, Phillip A. Armstrong, Jonathan C. Matti The morphology and anatomy of a Miocene long-runout landslide, Old Dad Mountain, California: implications for rock avalanche mechanics �������������������������������������������������������������������������������������������������� 38 Kim M. Bishop The discovery of the California Blue Mine ��������������������������������������������������������������������������������������������������� 44 Rick Kennedy Geomorphic evolution of the Morongo Valley, California ���������������������������������������������������������������������������� 45 Frank Jordan, Jr. New records
    [Show full text]
  • Community Wildfire Protection Plan
    Coombs-Hilliers COMMUNITY WILDFIRE PROTECTION PLAN SFC Prepared by: Strathcona Forestry Consulting GIS mapping: Madrone Environmental Services Ltd. August 2011 Community Wildfire Protection Plan: Coombs Hilliers Coombs Hilliers Community Wildfire Protection Plan Prepared for: Coombs-Hilliers Fire Protection Area Submitted by: Strathcona Forestry Consulting GIS Mapping by: Madrone Environmental Consulting Ltd. August 2011 This Community Wildfire Protection Plan was developed in association with: BC Ministry of Forests and Range Union of British Columbia and Municipalities Wildfire Management Branch Regional District of Nanaimo Coombs-Hilliers Volunteer Fire Department Administration Preparation: RPF Name (Printed) RPF Signature Date: ___________________ RPF No: _________ 2011 Page 2 Community Wildfire Protection Plan: Coombs Hilliers TABLE OF CONTENTS 1.0 INTRODUCTION 1.1 COOMBS-HILLIERS 3 1.2 COMMUNITY WILDFIRE PROTECTION PLAN PROGRAM 9 1.3 COOMBS-HILLIERS CWPP 11 2.0 THE SETTING 2.1 COMMUNITY PROFILES 12 2.2 TRANSPORTATION, COMMUNITY INFRASTRUCTURE 26 3.0 GOVERNMENT INFRASTRUCTURE 3.1 COMMUNITY VALUES 31 3.2 TOOLS AVAILABLE TO LOCAL GOVERNMENT 31 3.3 PUBLIC EDUCATION AND COMMUNICATION 32 3.4 PREVENTATIVE MEASURES 32 3.5 POLICE PROTECTION 35 3.6 FIRE PROTECTION 35 4.0 BIOGEOCLIMATIC 4.1 CLIMATE 40 4.2 PHYSIOGRAPHIC FEATURES 41 4.3 VEGETATION 42 4.4 NATURAL DISTURBANCE HISTORY 44 4.5 RECENT FIRE HISTORY 45 5.0 PREPARATION OF THE COMMUNITY WILDFIRE PROTECTION PLAN 47 6.0 ASSESSMENT 6.1 CANADIAN FOREST FIRE DANGER RATING SYSTEM 49 6.2 INTERFACE COMMUNITY FIRE HAZARD ASSESSMENT 61 6.3 HIRV MODELING 62 6.4 INTERFACE WILDFIRE THREAT RATING 62 7.0 ASSESSMENT RESULTS 66 8.0 INTERFACE WILDFIRE THREAT RATING INTERFACE FIRE HAZARD MAP 71 9.0 DISCUSSION 72 10.0 COMMUNITY ACTION PLAN 74 79 11.0 IMPLEMENTATION 12.0 REFERENCES 80 APPENDIX 1.
    [Show full text]
  • Debris Avalanche Deposits Associated with Large Igneous Province Volcanism: an Example from the Mawson Formation, Central Allan Hills, Antarctica
    The following document is a pre-print version of: Reubi, O., Ross, P.-S. et White, J.D.L. (2005) Debris avalanche deposits associated with Large Igneous province volcanism: an example from the Mawson Formation, Central Allan Hills, Antarctica. Geological Society of America Bulletin 117: 1615–1628 Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica O. Reubi 1,2,3 , P-S. Ross 1,2,4 and J.D L. White 1 1. Department of Geology, University of Otago, PO Box 56, Dunedin, New Zealand. 2. These authors contributed equally to this work. 3. Now at : Institut de Minéralogie et Pétrographie, Section des Sciences de la Terre, Université de Lausanne, BFSH-2, CH-1015 Lausanne, Switzerland. 4. Corresponding author. ABSTRACT An up to 180 m-thick debris avalanche deposit related to Ferrar large igneous province magmatism is observed at central Allan Hills, Antarctica. This Jurassic debris avalanche deposit forms the lower part (member m 1) of the Mawson Formation and is overlain by thick volcaniclastic layers containing a mixture of basaltic and sedimentary debris (member m 2). The m 1 deposit consists of a chaotic assemblage of breccia panels and megablocks up to 80 m across. In contrast to m 2, it is composed essentially of sedimentary material derived from the underlying Beacon Supergroup. The observed structures and textures suggest that the breccias in m 1 were mostly produced by progressive fragmentation of megablocks during transport but also to a lesser extent by disruption and ingestion of the substrate by the moving debris avalanche.
    [Show full text]
  • On the Transport Mechanism of Rockfalls and Avalanches by Jeffrey Michael Lacy a Thesis Submitted in Partial Fulfillment Of
    On the transport mechanism of rockfalls and avalanches by Jeffrey Michael Lacy A thesis submitted in partial fulfillment of the requirements for the degree OF Master of Science in Engineering Mechanics Montana State University © Copyright by Jeffrey Michael Lacy (1989) Abstract: In this thesis, a numerical model of a granular shear flow is developed. This model is two-dimensional and assumes the shearing granules to be identical, smooth, semi-elastic circular disks. The field containing these disks is bounded on the top and bottom by solid blocks of disks with the same properties. The field is bounded on the right and left by periodic boundaries. The top boundary block has an assigned horizontal velocity and overburden mass, and is unconstrained in the vertical direction. The base boundary block is immobile and does not permit scour. The numerical model is then used to test the hypothesis that, for large overburden pressures, collisions in the shearing region occur involving more than two particles, and that these multi-particle collisions act to reduce the shear strength of the dilatant granular flow. Flows were modeled for a variety of shear speeds and overburden pressures. Results of these simulations show that, although multi-particle collisions do occur with increasing frequency as overburden is increased, they do not have any significant effect on the shear strength of the granular flow. Therefore, this hypothesis is rendered invalid. ON THE TRANSPORT MECHANISM OF ROCKFALLS AND AVALANCHES by Jeffrey Michael Lacy A thesis submitted in partial fulfillment of the requirements for the degree r of Master of Science in Engineering Mechanics MONTANA STATE UNIVERSITY Bozeman, Montana April 1989 ii APPROVAL of a thesis submitted by Jeffrey Michael Lacy This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citations, bibliographic style, and consistency, and is ready for submission to the College of Graduate Studies.
    [Show full text]
  • Fernpass Rockslide, Tyrol, Austria)
    Geo.Alp, Vol. 3, S. 147–166, 2006 SPATIAL FEATURES OF HOLOCENE STURZSTROM-DEPOSITS INFERRED FROM SUBSURFACE INVESTIGATIONS (FERNPASS ROCKSLIDE, TYROL, AUSTRIA) Christoph Prager1, 2, Karl Krainer1, Veronika Seidl1 & Werner Chwatal3 With 11 figures and 2 tables 1 University of Innsbruck, Institute of Geology and Paleontology, Innrain 52, A-6020 Innsbruck, Austria 2 alpS Centre for Natural Hazard Management, Grabenweg 3, A- 6020 Innsbruck, Austria 3 Technical University of Vienna, Institute of Geodesy and Geophysics, Gußhausstrasse 27-29, A-1040 Vienna, Austria Abstract A low frequency Ground Penetrating Radar (GPR) system was successfully applied for near subsurface explorations at different accumulation areas of the fossil Fernpass rockslide (Tyrol, Austria), which is one of the largest mass movements in the Alps. Based on detailed field studies and calibrated by drillings down to a depth of 14 m, the reflectors of the processed GPR-data could be well attributed to different deposition- al units. As a result, the distal rockslide deposits feature intensively varying accumulation geometries and are up to approximately 30 m thick. In addition, the topographically corrected GPR data show that the Toma, i.e. cone-shaped hills composed of rockslide debris, show deeper roots than the topographically less elevated rockslide successions between them. Compiled field-, drilling- and GPR-data indicate that the accumulation pattern and spread of the investigated rockslide deposits was obviously predisposed by the late-glacial val- ley morphology and that the Sturzstrom surged upon groundwater-saturated, fine-grained lacustrine sedi- ments. Thus we assume that dynamic undrained loading, reducing the effective stresses between the rock- slide and its incompetent substrate, enabled the extremely long run-out distance of the sliding mass mea- suring up to at least 15.5 km.
    [Show full text]
  • Natural History Feeding
    BRITISH COLUMBIA VANCOUVER ISLAND GEOLOGY The Creation of the Johnstone Strait Over a span of thousands of years and a combination of processes such as tectonics, volcanism, erosion and glaciation the 110km Johnstone Strait off of Vancouver Island was formed. Formally known as Wrangellia, a land mass that collided with North America causing it to fold and buckle forming the many of the mountains and ranges we associate with British Columbia today. The formation of the narrow channels that make up Northeastern Vancouver Island dates back to the ice ages when glacial ice sheets settled in the area. During the Pleistocene Epoch Ice Age ice sheets carved their way through the igneous rock or the channel creating what is now known as Johnstone Strait, Queen Charlotte strait, and the Discovery Passage. Glacial carving transpires through the slow movement of the ice sheet. Due to their sheer size and weight combined with gravity ice sheets move slowly down mountain valleys, and across plains. As glaciers move they sculpt the land via erosion and deposition. While they gradually move across the landscape the ice erodes the surface beneath it, creating fjords, glacial valleys, and horns. During this erosion the ice actually picks up and retains sediment and particles depositing them along the way. This process of deposition, depositing of material as the glacier retreats and melts away, forms moraines which are narrow ridges that show where the ice used to be. Robson Bight Ecological Reserve ceremonial purposes. Ubiquitous to the area are manmade geological features known as clam beds. For the First Nations’ people clams were a staple not only for their food source but for their economy as Ecological Reserves were formed in Canada in 1971 as a way to encourage the preservation of natural well for they used them in trade with other tribes.
    [Show full text]
  • Fractal Fragmentation of Rocks Within Sturzstroms: Insight Derived from Physical Experiments Within the ETH Geotechnical Drum Centrifuge
    Granular Matter (2010) 12:267–285 DOI 10.1007/s10035-009-0163-1 Fractal fragmentation of rocks within sturzstroms: insight derived from physical experiments within the ETH geotechnical drum centrifuge Bernd Imre · Jan Laue · Sarah Marcella Springman Received: 5 May 2009 / Published online: 21 April 2010 © Springer-Verlag 2010 Abstract An investigation of the behaviour and energy 1 Introduction budget of sturzstroms has been carried out using physical, analytical and numerical modelling techniques. Sturzstroms The downslope mass movement of dry, loose rock mate- are rock slides of very large volume and extreme run out, rial is a common geological process. Such events are often which display intensive fragmentation of blocks of rock due referred to as dry rock falls, rock slides or rock topple [1]. to inter-particle collisions within a collisional flow. Results The mechanics of such phenomena are generally well under- from centrifugal model experiments provide strong argu- stood in terms of the competition between gravity, inertia ments to allow the micro-mechanics and energy budget of and inter-granular friction (e.g. [2–5] and others). However, sturzstroms to be described quantitatively by a fractal com- a rare category of dry rock slides, or in few cases rock falls, minution model. A numerical experiment using a distinct exists in which vast horizontal distances are travelled with element method (DEM) indicates rock mass and boundary only a comparatively small vertical drop in height. They turn conditions, which allow an alternating fragmenting and dilat- into sturzstroms (Fig. 1;[6]) during run out and appear to ing dispersive regime to evolve and to sustain for long enough travel as if the inter-granular coefficient of friction, which to replicate the spreading and run out of sturzstroms without usually controls the downslope motion of dry rock debris, needing to resort to peculiar mechanism.
    [Show full text]
  • Late Pleistocene Palaeoenvironments, Archaeology, and Indicators of a Glacial Refugium on Northern Vancouver Island, Canada
    Late Pleistocene palaeoenvironments, archaeology, and indicators of a glacial refugium on northern Vancouver Island, Canada by Christopher Franklin George Hebda B.A., University of Victoria, 2014 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF ARTS in the Department of Anthropology © Christopher Franklin George Hebda, 2019 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. We acknowledge with respect the Lekwungen peoples on whose territory the university stands and the Songhees, Esquimalt and W̱ SÁNEĆ peoples whose historical relationships with the land continue to this day. ii Supervisory Committee Late Pleistocene palaeoenvironments, archaeology, and indicators of a glacial refugium on northern Vancouver Island, Canada by Christopher Franklin George Hebda B.A., University of Victoria, 2014 Supervisory Committee Dr. Quentin Mackie, Department of Anthropology Co-Supervisor Dr. Duncan McLaren, Department of Anthropology Co-Supervisor iii Abstract Recent research has revealed human settlement on the Pacific coast of Canada extending back nearly 14,000 years, but much of the late Pleistocene record is unknown due to shifting sea levels, poor understanding of Cordilleran ice extent, and limited research on the biota of the coast during this time. This study, undertaken in Quatsino First Nation and ‘Namgis First Nation territories as part of the Northern Vancouver Island Archaeology and Palaeoecology Project, employs modern multi-proxy analysis of lake sediment cores from two sites on northern Vancouver Island to reconstruct palaeoenvironments during and immediately following the Fraser Glaciation in coastal British Columbia.
    [Show full text]
  • Eastern Vancouver Island (#196)
    EASTERN VANCOUVER ISLAND (#196) The Eastern Vancouver Island ecoregion stretches along the eastern slopes of the Vancouver Island Ranges to the Pacific Ocean. The forests are characterized by Douglas-fir, western hemlock and grand fir, with scattered examples of globally rare Garry oak ecosystem. It supports more biological diversity than anywhere else in the province and contains many of BC’s most ecologically significant estuaries. There are 59 species at risk that have been documented here, and 38 species that are of global conservation concern. Just over 93% of this ecoregion remains in natural cover and 13.8% is within conserved/protected areas. LOCATION The Eastern Vancouver Island ecoregion stretches along the eastern slopes of the Vancouver Island Ranges to the Strait of Georgia between Victoria and Nanaimo. This ecoregion is part of BC’s Coastal Douglas-Fir Biogeoclimatic Zone, and it is the northern extension of the Central Pacific Coastal Forests, a region of coastal temperate rainforests that extends through southern Oregon to the northern tip of Vancouver Island. CLIMATE/GEOLOGY The climate of the Eastern Vancouver Island ecoregion is charac- terized by warm, dry summers and wet, very mild winters. Frosts are common in winter, but snow cover at sea level is rare. The mean annual temperature is approximately 9⁰C, with a summer mean of 14⁰C and a winter mean of 3.5⁰C. Mean annual precip- itation ranges from 800 millimetres at lower elevations to 2,500 millimetres at higher elevations. The ecoregion contains low relief on the coast and in valleys, to high mountain peaks in the Vancouver Island ranges toward the central and northern end of the island.
    [Show full text]