Occurrence and Genesis of Apline Linears Due To
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OCCURRENCE AND GENESIS OF ALPINE LINEARS DUE TO GRAVITATIONAL DEFORMATION IN SOUTH WESTERN, BRITISH COLUMBIA Derek Kinakin BSc, Simon Fraser University 2002 THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE In the Department of Earth Sciences O Kinakin 2004 SIMON FRASER UNIVERSITY Fa11 2004 All rights reserved. This work may not be reproduced in whole or in part, by photocopy or other means, without permission of the author. APPROVAL Name: Derek Kinakin Degree: MSc Title of Thesis: Occurrence and genesis of alpine hears due to gravitational deformation in South Western, British Columbia Examining Committee: Chair: Dr. Peter Mustard Associate Professor Department of Earth Sciences, SFU Dr. Doug Stead Senior Supervisor Professor Department of Earth Sciences, SFU Dr. Brent Ward Supervisor Associate Professor Department of Earth Sciences, SFU Bruce Thomson, MSc., PGeo. Supervisor Ministry of Water, Land & Air Protection (Ret.) Tom Stewart, MSc., PEng. External Examiner Civil Engineer B.C. Hydro Date DefendedlApproved: November 15,2004 DECLARATION OF PARTIAL COPYRIGHT LICENCE The author, whose copyright is declared on the title page of this work, has granted to Simon Fraser University the right to lend this thesis, project or extended essay to users of the Simon Fraser University Library, and to make partial or single copies only for such users or in response to a request from the library of any other university, or other educational institution, on its own behalf or for one of its users. The author has further granted permission to Simon Fraser University to keep or make a digital copy for use in its circulating collection, and, without changing the content, to translate the thesislproject or extended essays, if technically possible, to any medium or format for the purpose of preservation of the digital work. The author has further agreed that permission for multiple copying of this work for scholarly purposes may be granted by either the author or the Dean of Graduate Studies. It is understood that copying or publication of this work for financial gain shall not be allowed without the author's written permission. Permission for public performance, or limited permission for private scholarly use, of any multimedia materials forming part of this work, may have been granted by the author. This information may be found on the separately catalogued multimedia material and in the signed Partial Copyright Licence. The original Partial Copyright Licence attesting to these terms, and signed by this author, may be found in the original bound copy of this work, retained in the Simon Fraser University Archive. Simon Fraser University Library Burnaby, BC, Canada Alpine linears are found on many slopes in south western, British Columbia. The genesis of these features is commonly related to gravitational deformation of rock slopes. A preliminary stress analysis of selected ridge morphologies indicates that the resulting stress fields are different for each basic ridge type analysed, indicating that various deformation mechanisms may be active in producing alpine linears. An integrated system of GIs and numerical modelling is applied to a study of Mount Mercer, British Columbia. Detailed geomorphic and engineering geological mapping indicates that linears observed along the ridgeline of Mount Mercer are due to rock slope deformations. Potential failure mechanisms are evaluated for kinematic feasibility and resulting failure morphology. The results of the study indicate that toppling does not appear to be a suitable rock mass deformation mode for the failures at Mount Mercer; bi-planar failure and rock slumping are demonstrated to be suitable for the rock slope failures. DEDICATION For my parents, Peggy and Mike. And For Krista. ACKNOWLEDGEMENTS The support of my supervisory committee, Dr. Brent Ward and Mr. Bruce Thornson, has been instrumental in the completion of this work. The comments and suggestion from my external examiner, Mr. Tom Stewart, have been greatly appreciated. The assistance of my fellow students, Marc-Andre Brideau and Nichole Boultbe, has been a key factor in the completion of the research presented in this document. The teaching, advice, and encouragement provided by my senior supervisor, Dr. Doug Stead, has resulted in my significant personal growth as a research scientist and applied geomorphologist. TABLE OF CONTENTS .. Approval ...........................................................................................................................II ... Abstract ..........................................................................................................................III Dedication....................................................................................................................... iv Acknowledgements ........................................................................................................ v Table of Contents ........................................................................................................vi List of Figures .............................................................................................................ix List of Tables ..........................................................................................................xiv Chapter 1 Introduction .............................................................................................1 1. 1 Alpine linears................................................................................................. 2 1. 1.1 Geomorphology of alpine linears............................................................... 4 1.1.2 Processes forming alpine linears .............................................................. 6 1.2 Rock slope interaction matrix ......................................................................9 1.2.1 Interaction matrix details ......................................................................... 10 1.3 Summary .....................................................................................................12 Chapter 2 Analysis of the distribution of stress in natural ridge forms ............ 13 2.1 Introduction ................................................................................................. 13 2.2 Stress modelling and analysis .................................................................. 13 2.3 Past methods and examples ....................................................................... 14 2.4 Methods ...................................................................................................... 15 2.4.1 Model properties...................................................................................... 15 2.4.2 Simulation of rock mass properties ....................................................... 15 2.4.3 Geometry creation ................................................................................... 16 2.4.4 Procedures ..............................................................................................18 2.5 Results .....................................: .................................................................. 19 2.5.1 Model validation ....................................................................................19 2.5.2 Stress distributions with elastoplastic materials ......................................20 2.5.3 Gravity loading (K = 0.3) .......................................................................... 20 2.5.4 Tectonic and gravity loading (K=0.5. 1. and 2) ........................................ 23 2.6 Discussion................................................................................................... 27 2.7 Conclusions................................................................................................. 30 Chapter 3 Tools for landslide analysis ................................................................. 32 3.1 Introduction .................................................................................................32 3.1.1 Previous GIs applications in engineering geology / geotechnics ............32 3.1.2 GIs applications for site investigation.................................................... 34 3.2 Tool integration: The landslide research toolbox ....................................... 35 3.2.1 Digital data collection and storage........................................................... 36 3.2.2 Data manipulation and visualization ........................................................40 3.2.3 Modelling and analysis ............................................................................44 3.2.4 Continuing work on the "Landslide Research Toolbox" ........................... 45 Summary ..................................................................................................... 46 Chapter 4 A field investigation of sackung at Mount Mercer. British Columbia ................................................................................................................47 Study location.............................................................................................. 47 Local and regional physiography ................................................................ 48 Climate ........................................................................................................ 48 Bedrock geology ......................................................................................... 50 The Chilliwack Group .............................................................................