Earth Sciences - Theses, Dissertations, and other Required Graduate Degree Essays

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The influence of tectonic structures on rock mass quality and implications for rock slope stability

Date created: 
2005
Abstract: 

A field, laboratory and numerical modelling methodology was developed to investigate the influence of tectonic structure on rock mass quality and implications for rock slope stability. The fundamental components of this methodology include a full description of the rock mass (GSI, number of joint sets, block size and shape, weathering) and discontinuities (orientation, surface roughness, spacing, persistence, infill, seepage) in all accessible sections of the landslide, laboratory work (point load testing and thin section descriptions), and numerical modelling (limit equilibrium, finite difference and distinct element). Detailed fieldwork performed at the Aishihik River landslide, Hope Slide, and East Gate Landslide showed that pre-existing tectonic structures can significantly reduce the rock mass quality and facilitate the development of release surfaces. Numerical models of conceptual and natural slopes have shown that different representation of faults and related damage zone has a significant influence on the shape, volume, and failure mechanism of a landslide.

Document type: 
Thesis
File(s): 
Department: 
Department of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Three-dimensional kinematic controls on rock slope stability conditions

Date created: 
2010
Abstract: 

This thesis investigates the three-dimensional influence of discontinuity sets and topography on kinematics of rock slope stability and failure mechanisms. A field data collection methodology was developed to provide the inputs to a slope stability investigation that utilises three-dimensional geometric, limit equilibrium and distinct element codes. Conceptual slope geometries in addition to three case studies are employed to evaluate the influence of discontinuity set orientation and lateral kinematic confinement on the failure mechanism and slope stability conditions. The influence of varying the discontinuity persistence and block size in a three-dimensional distinct element code are also investigated. Systematic studies of these parameters are performed for the planar sliding and block toppling failure mechanisms. This thesis presents the first detailed description and slope stability analysis of the McAuley Creek Landslide and the Chehalis Lake Landslide. New data and analyses of the potentially unstable rock mass at Third Peak on Turtle Mountain are also presented. Two recently developed representations of complex topography in the three-dimensional distinct element code are applied to the case studies. The results obtained in this thesis are compared to the description of other local and international large rock slope failures published in the literature.

Document type: 
Thesis
File(s): 
Senior supervisor: 
D
Department: 
Department of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (Ph.D.)

Conuma River and Leagh Creek intrusive complexes: windows into mid-crustal levels of the Jurassic Bonanza island arc, Vancouver Island, British Columbia

Author: 
Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

The Conuma River and Leagh Creek intrusive complexes are examples of mid-crustal portions of the Jurassic Bonanza island arc, located on Vancouver Island, British Columbia, Canada. The Conuma River locality exhibits layered intrusions, consisting of alternating hornblenditic and hornblende gabbroic cumulates, occurring with numerous, contemporaneous small volume mafic to intermediate intrusions in tonalitic rocks. The Leagh Creek intrusions exhibit extensive silicic and basaltic magma mingling. Both complexes are interpreted as products of multiple magma pulses into the solidifying host intrusions. Two new radiometric hornblende Ar-Ar ages suggest Early to Middle Jurassic ages for two intrusions from each of the complexes. Geochemical crystallization modeling shows a genetic link between the Conuma River cumulate hornblenditic and non-cumulate hornblende gabbroic intrusions via dominantly olivine fractionation. Conversely, most of the intrusions of both complexes cannot be related by simple crystallization modeling, suggesting a complex history, involving magma mingling and assimilation processes.

Document type: 
Thesis
File(s): 
Senior supervisor: 
D
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Multi-scale analysis of multiparameter geophysical and geochemical data from active volcanic systems

Author: 
Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

Persistently active volcanoes present short and long term variation in their magmatic, hydrothermal, and/or hydrogeological systems. As magma is rarely accessible on the surface, investigation of the dynamic behaviour of the hydrothermal system is an indirect approach to study the underlying magmatic activity. Variations in volume, mass and flow direction of the water are expressed through change and generation of local disturbances of potential-fields, such as gravity or Self-potential. The source generating the potential-field signal is a non-unique solution, making it very difficult to model. This study uses a modern signal analysis technique, Multi-scale wavelet tomography, to accurately determine the depths of these sources. The accuracy of Multi-scale wavelet tomography on Self-potential data was tested on three volcanoes (Masaya, Stromboli, Waita) in comparison with water depths calculated by more traditional geophysical methods. Traditional inverse gravity modeling is also used to better constrain the non-unique solution of potential-fields. This study also investigates two persistently active volcanoes, Masaya and Kawah Ijen, through time-series and spatial surveys to monitor change occurring within them. This study shows that a well established and mature hydrothermal system can show limited surface expression as at Kawah Ijen volcano, while an apparently low intensity hydrothermal system can have an extensive and complex system beyond its active crater, such as at Masaya volcano. The hydrothermal system of Masaya is spatially controlled by a ring fault structure and has been stable between 2006 and 2009. In contrast, on Kawah Ijen, the intense and well-established hydrothermal system is completely self-sealed within the upper volcanic edifice and can only release the pressurized fluids and gas through the active crater. Nevertheless, between 2006 and 2008, the hydrological system showed significant vertical change due to seasonal effects. By integrating a wide variety of distinct, complementary techniques to a number of persistently active volcanoes, over an extended period of time, it is possible through accumulation of baseline information, to characterize the components of signals detected on volcanoes. A more accurate understanding of the volcanic system as a whole, through accurate constraint of the different volcanic signals, is fundamental in improving volcano monitoring and hazard mitigation.

Document type: 
Thesis
File(s): 
Senior supervisor: 
G
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (Ph.D.)

Sedimentology, stratigraphy, and provenance of the Lower Cretaceous Jackass Mountain Group, Chilko Lake area, British Columbia, Canada

Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

The Cretaceous Jackass Mountain Group (JMG) near Chilko Lake in south central British Columbia is an approximately 2 km-thick, shallow-marine succession composed of immature, volcanic-rich sandstone, with subordinate mudstone and conglomerate. Deposition of the JMG occurred within the Methow Basin along the western margin of North America, over the accreted Cadwallader, Bridge River and Methow Terranes. Four facies associations represent sedimentation during Albian to Cenomanian time, and are characterized by nearshore and deltaic deposits that accumulated in close proximity to an active volcanic arc system and older uplifted volcanoplutonic arc rocks. Correlation between disparate Cretaceous sedimentary packages was tested by petrographic, geochemical, and detrital zircon analyses. These analyses indicate that the Chilko Lake and the Camelsfoot Range JMG, now offset across the Yalakom Fault, are correlative; however, a direct correlation to the Taylor Creek Group of the Tyaughton Basin remains tenuous.

Document type: 
Thesis
File(s): 
Senior supervisor: 
J
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Evaluation of subaerial landslide hazards in Knight Inlet and Howe Sound, British Columbia

Author: 
Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

This thesis evaluated hazards from subaerial (originating above sea level) landslide-induced tsunamis in Knight Inlet and Howe Sound. Field assessments were conducted at Adeane Point and Mount Gardner. GIS was used at site and inlet scales to compile existing map data, to map submarine slide deposits, to measure topographic parameters, and to integrate observations. Modelling at Adeane Point employed kinematic, limit equilibrium (SWEDGE) and discrete element (3DEC) analyses in order to estimate the volume of a potential landslide. Results suggest that the hazard from subaerial slide-induced waves is high in Knight Inlet, particularly in the area between Adeane Point and Glacier Bay, whereas, when compared with Knight Inlet, the hazard in Howe Sound appears considerably less. Modelling results suggest that topography and discontinuity persistence are the leading controls on failure volume. A preliminary catalogue of techniques for assessing hazards from slide waves was created, and related issues were discussed.

Document type: 
Thesis
Senior supervisor: 
D
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Thermotectonic evolution of the Wolverine metamorphic complex, British Columbia: limitations on the use of combined ion exchange and net-transfer reaction geothermobarometry at upper amphibolite-facies metamorphism

Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

Peak metamorphism of the Wolverine metamorphic complex (WMC) occurred at conditions of 770°-830°C and 7.2-10.4 kbars, and was accompanied by partial melting and the development of tight to isoclinal northeast-vergent folds that are axial planar to a transposition foliation. The WMC is modelled as a diffuse northeast-vergent shear zone that formed beneath a southwest-vergent panel of rocks as the orogenic wedge detached and translated northeastward during Mesozoic contraction. Juxtaposition of Middle Jurassic greenschist-facies upper crustal rocks against upper amphibolite-facies rocks of the WMC, which contain Eocene 40Ar/39Ar cooling ages, suggests that the WMC remained at deep crustal levels until it was rapidly exhumed in the Eocene along the normal Wolverine fault. Mineral reaction and disequilibrium textures indicate a near-isothermal decompression path from 7.2-10.4 kbars to below 4 kbars, corresponding to a minimum of 11 km of exhumation prior to cooling below ~650°C.

Document type: 
Thesis
Senior supervisor: 
D
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Dynamics of a small surge-type glacier, St. Elias Mountains, Yukon Territory, Canada: characterization of basal motion using 1-D geophysical inversion

Author: 
Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

The dynamics of a small surge-type glacier are investigated as part of a study to characterize glacier response to climate in southwest Yukon Territory, Canada. DEMs of the glacier surface and bed are constructed from surface elevation and ice thickness data. Measured surface velocities are higher than expected for a surge-type glacier in its quiescent phase over the upper 3500m of the 5km-long glacier, but much lower than typical surge velocities. Flowline basal velocities are reconstructed from the measured surface velocities using a 1-D geophysical inverse model. Control tests are used to validate the inversion scheme, and sensitivity tests are performed to evaluate the influence of uncertain parameters. Inversion of the measured surface velocities reveals an unusually high contribution of basal motion to the overall motion. Based on these results and several other lines of evidence, we suggest that the glacier may be undergoing a slow surge.

Document type: 
Thesis
Senior supervisor: 
G
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Glacier melt modelling in the Donjek Range, St. Elias Mountains, Yukon Territory

Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2009
Abstract: 

Toward addressing the challenges associated with regional glacier melt modelling, I investigate the physical mechanisms of glacier melt using energy balance models, then test empirical temperature-index melt models for regional applications. First, five energy balance models are applied to two glaciers in the Donjek Range, St.~Elias Mountains in order to quantify the differences between various treatments of the glacier surface temperature and subsurface heat flux. A model that assumes a constant 0°C surface temperature overestimates cumulative melt by 9–13%, but a simple model that computes surface temperatures from the residual of the energy balance yields significant improvement. Second, I evaluate the transferability of spatially-distributed temperature-index melt models through the application of calibrated model parameters to periods and locations that differ from those used for calibration. Results show that the calibrated model parameters can be transferred between the study glaciers with minimal reductions in skill.

Document type: 
Thesis
File(s): 
Senior supervisor: 
G
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)

Sedimentology and stratigraphy of the Lower Cretaceous Jackass Mountain group, Camelsfoot Range, British Columbia

Author: 
Date created: 
2008
Abstract: 

The Cretaceous Jackass Mountain Group (JMG), within the Camelsfoot Range of south-central B.C., is a >2 km thick succession of marine and nonmarine volcanic-rich, feldspathic litharenite and lithic arkose sandstone, lesser mudstone, and minor conglomerate, ranging early Aptian to Cenomanian/Turonian age. The JMG was deposited in the Jura-Cretaceous Methow-Tyaughton Basin, a piggyback basin that formed atop the accreting Bridge River, Cadwallader, and Shulaps terranes, between west coast North America and impending Insular Belt terranes. It is likely that most JMG sediment was derived from first cycle weathering of nearby source rocks dominated by a mix of moderately weathered volcanic and plutonic complexes. Three facies associations were identified that essentially represents two-thousand metres of sand-rich submarine fan turbidites, delta front or prodelta deposits, and nonmarine sedimentation. Combined, the facies associations represent an overall regression in the Methow-Tyaughton Basin as accreting terranes eventually closed the basin and amalgamated it onto the continent.

Document type: 
Thesis
File(s): 
Senior supervisor: 
P
Department: 
Dept. of Earth Sciences - Simon Fraser University
Thesis type: 
Thesis (M.Sc.)