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1
Fleming, Erin Mattea. "Reconstruction of holocene environmental changes in northern British Columbia using fossil midges." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2811.
Full textAbstract:
Lake sediments contain the remains of midge communities that may be used as biological proxies for inferring past environmental changes. Freshwater midges, including Chironomidae and Chaoboridae, from two alpine tarns (Pyramid Lake and Bullwinkle Lake) in the Cassiar Mountains of northern British Columbia were used to estimate Holocene palaeotemperature changes, and more specifically, to test for the presence of the Milankovitch thermal maximum, an early Holocene warm interval coinciding with peak Holocene summer solar insolation. Mean July air temperatures were reconstructed using midge-inference models developed via weighted averaging-partial least squares (WA-PLS) regression. Cold-tolerant midge taxa dominate the stratigraphies from both Pyramid and Bullwinkle Lakes; however, warm-adapted species are more common in Bullwinkle Lake. Early Holocene warming is apparent at both lakes, however it is unclear whether this is indicative of the Milankovitch thermal maximum. A decrease in temperature occurs from 8,700-7,900 cal. yr BP at Pyramid Lake, around the same time that the 8,200 cal. yr BP cooling event occurred in the northern hemisphere. During the middle Holocene, records from Pyramid Lake indicate an overall decrease in temperature, with a short period of warmer temperatures that peak at 5,100 cal. yr BP. Temperatures fluctuate little during this time at Bullwinkle Lake. A short warming phase is apparent at both lakes during the late Holocene. July temperatures are highest at 2,000 cal. yr BP (10.5°C) in Pyramid Lake and at 1,200 cal. yr BP (13°C) in Bullwinkle Lake. Thereafter, temperatures return to what they were before the warming occurred, and at Bullwinkle Lake, vary little throughout the remainder of the Holocene.
2
Mazzucchi, David. "Holocene environmental reconstruction of the Cassiar region, northwestern British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ53009.pdf.
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3
Feick, Jenny L. "Evaluating ecosystem management in the Columbia Mountains of British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/NQ54777.pdf.
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4
Ball, Mathew C. N. "Geology of the McDame gold camp, Cassiar, British Columbia, implications for lode-gold metallogenesis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22444.pdf.
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5
Sketchley, Dale Albert. "The nature of carbonate alteration in basalt at Erickson Gold Mine, Cassiar, north-central British Columbia." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26075.
Full textAbstract:
The Erickson mine is within the McDame lode gold camp, aproximately 12 km southeast of Cassiar, British Columbia. The mine is in mafic volcanic, ultramafic and sedimentary rocks of the Upper Paleozoic to Lower Mesozoic Sylvester Allochthon.
Gold-silver mineralization occurs in white quartz veins that are mostly within mafic volcanic rocks. K-Ar dates from sericite in gold-silver-bearing white quartz veins indicate that mineralization occurred in the Early Cretaceous at about 130 Ma. Thus, these veins predate the mid-Cretaceous Cassiar batholith and Lower Cretaceous and Early Tertiary plutons in the immediate area. However, the Early Cretaceous date probably represents a thermal event, precursor to emplacement of the Cassiar batholith, which may have caused circulation of the meteoric fluids responsible for the veins.
Rocks within the Erickson mine were affected by four types of alteration: synvolcanic hydrotherma1, regional metamorphic, epigenetic hydrothermal and contact metamorphic. The most common type is epigenetic carbonatization of basalt, which occurs as we11-developed envelopes around gold-silver-bearing white quartz veins and carbon veins. Dolomite veins are surrounded by similar carbonate alteration envelopes; these veins postdate white quartz veins and carbon veins. Disseminated and fracture-controlled carbon may be present around white quartz veins and carbon veins.
An idealized model of carbonate alteration envelopes is presented based on field observations and mineralogical studies.
Rocks within carbonate alteration envelopes are composed of ankerite, siderite, dolomite, quartz, sericite, kaolinite, pyrite, carbon and minor titanium oxides. A generalized model of mineral species distribution throughout the envelopes around white quartz veins, carbon veins and dolomite veins was also developed.
Mass balance calculations, using Gresens' (1967) metasomatic
equation, indicate the following compositional changes around a
gold-silver-bearing white quartz vein: gain of K₂O and SiO₂ ; loss
of Na₂O, Fe₂O₃ and MgO; loss of CaO from the outer portion of the
envelope and gain in the inner. Loss on ignition and the
alteration mineral assemblage indicate gain of at least CO₂ , H₂O
and S.
Geochemistry of carbonate alteration envelopes was investigated using an aqua regia digestion with multi-element inductively coupled plasma (ICP) analyses and gold-silver fire assays. The ICP analyses were compared to X-ray fluorescence (XRF) analyses to determine the range of extraction and to assist in interpretation. The comparison indicates that if there is strong enrichment in carbonate alteration envelopes surrounding gold-silver-bearing white quartz veins, the ICP analyses will show these patterns well. Strong enrichment in potassium, barium, boron and arsenic, and sporadic enrichment in gold, silver, copper, lead, zinc and antimony occur in carbonatized basalt around gold-silver-bearing white quartz veins.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
6
Israel, Steve A. "Tectonic significance of the Atnarko complex, Coast Mountains, British Columbia." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/838.
Full textAbstract:
The Atnarko complex located in west-central British Columbia comprises pre-Early Jurassic metavolcanic and metasedimentary rocks, termed the Atnarko assemblage, which is structurally interleaved with Late Triassic to Early Cretaceous orthogneiss. The Atnarko assemblage correlates with continental margin assemblages found within the Coast plutonic complex. Tectonic interaction between the Insular and Intermontane superterranes resulted in several phases of deformation including; 1) poorly preserved Jurassic deformation, 2) Early to mid-Cretaceous, southwest to west directed, compression, 3) mid-Cretaceous, north to northeast directed, compression, 4) mid- to Late Cretaceous dextral and sinistral ductile/brittle shearing, and 5) post latest Cretaceous brittle faulting. Peak metamorphism coincides with generation of migmatite in the Early Cretaceous (~117-115 Ma) and is contemporaneous with penetrative ductile fabrics. The Atnarko complex had cooled below 350°C by the Late.
Comparison of the Atnarko complex to equivalent portions of the orogen along strike, indicates a post mid-Cretaceous change in structural style. To the northwest the orogen records continued southwest-directed compression which dominates the deformation style; while to the southeast large dextral strike-slip faults dominate. Relative plate motions between ca. 70-60 Ma indicate that dextral transpression occurred between the Kula and North American plates. Strain during this transpressive deformation was partitioned into compressive and translational regions. The Atnarko complex area is situated at the transition between translation and compression.
The conditions of the lower and middle crust within the orogen were established by how strain was partitioned across the orogen. The distributed strain also shaped how the orogen responded to Tertiary extension. Continued compression to the northwest of the Atnarko complex led to increased crustal thickness and partial melting of lower and middle crust in the Tertiary. Conversely, the cessation of compression in the southeast lead to a more stable (i.e. cooler) crustal lithosphere. A change in relative plate motions in the early Tertiary triggered full-scale, orogen-perpendicular, collapse in the northwest facilitated by decoupling between the middle and lower crusts along thermally weakened layers. Localized orogen-parallel extension occurred in the southeast which was kinematically linked to large dextral strike-slip faults where the upper crust remained coupled to the middle and lower crust.
7
Jones, Penelope Sarah Ann. "Postglacial chronology of large earthflows in south-central British Columbia." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28842.
Full textAbstract:
Fifty-three earthflows in south-central British Columbia were identified
from an air photograph search and from a review of previous geologic reports. Many have parallel 'en echelon1 lateral deposits indicative of several
movement phases during the postglacial period, and some have been active
during the present century up to the time of the study. The purpose of this study was to date phases of earthflow activity during the postglacial period and relate them to climatic fluctuations.
Earthflows in the study area are concentrated in serpentinised peridotite, basalt, sediments (mainly volcaniclastics), and other volcanics. Earthflows take place preferentially down dip in sediments and many are associated
with fault lines. All earthflow materials, except those derived from serpentinised peridotite, weather to montmorillonite-rich material, and each yields a characteristic grain-size distribution. Earthflow gradient in the study area depends upon material type, indicating that earthflow texture and mineralogy govern shearing resistance and hence partially determine characteristic
slope angles.
Earthflow movement during the past 60 years was investigated using air photograph chronosequences dating back to 1928. Reactivations of six flows were identified in the period 1950 to 1960, and an analysis of precipitation records from four stations around the study area showed that the level of winter precipitation increased around 1950. It was concluded that the observed
reactivation was a response to rising groundwater levels during a period of increased winter precipitation.
Earthflow movement and climatic fluctuations over the last 200 years were investigated in an analysis of tree-ring width records at four sites. Moist phases were recorded in the periods 1800-1830, 1870-1920 and from 1945 to the present. Compression wood formation at three sites corresponded with moist phases, so it was concluded that, over the last two centuries, earthflow movement was probably coincident with phases of higher precipitation.
A postglacial climatic chronology was inferred from published pollen analyses and from Neoglacial ice fluctuations, both within and outside the study area. New palynological data were collected from Red Mountain, a high elevation site in the west of the study area. These showed a two-phase cooling period following the close of the Hypsithermal. The first cooling period took place around 6-7,000 BP, and the second around 3,000 BP.
Earthflow movement during the postglacial period was analysed using radiocarbon dates, tephrochronology, stratigraphy, carbonate accumulation, and earthflow morphology. Data from twenty-one sites showed that movement was concentrated mainly after 7,000 BP, and at several sites the stratigraphic position of the Bridge River tephra dated movement around 2,400 BP. It was concluded that, at this longer timescale, movement at many sites could be attributed to post-Hypsithermal climatic deterioration.Arts, Faculty of
Geography, Department of
Graduate
8
Reid, Leslie. "Structural evolution of the Isaac Lake Synclinorium, Cariboo Mountains, British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20850.pdf.
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9
Garwin, Stephen Lee. "Structure and metamorphism in the Niagara Peak area, western Cariboo Mountains, British Columbia." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26259.
Full textAbstract:
A more than 2000 m thick sequence of Hadrynian to Paleozoic Snowshoe Group metasedimentary rocks of the Omineca Belt (OMB) is exposed near Niagara Peak in the western Cariboo Mountains, central British Columbia. This package contains the northern extremity of the Shuswap Metamorphic Complex and lies 30 km northeast of the accretionary boundary with Intermontane Belt (IMB) Mesozoic sedimentary and volcanic rocks (Quesnellia Terrane) and Upper Paleozoic (?) ophiolitic and sedimentary rocks (Slide Mountain Terrane).
Four phases of folding (D₁-D₄) are recognized. D₁ consists of isoclinal folds and transposed compositional layering. D₂ commonly forms southwest verging, open to close folds with subhorizontal axes and moderately northeast dipping axial surfaces. In the eastern part of the area, divergent fanning of D₂ axial surfaces and a reversal of vergence direction occur about a map-scale synform characterized by greater strain, bimodal fold style and a locally penetrative axial planar cleavage. D₃ and D₄ form orthogonal upright open buckles with respective northwest and northeast trending axes. Steeply dipping normal and minor reverse faults crosscut all fold structures, displaying minor offsets.
Prograde regional metamorphism reached greenschist grade late in D₁. Staurolite and kyanite growth accompanied D₂, followed by postkinematic sillimanite generation under conditions of approximately 635° C and 5 kb. D₃ associated sericite-chlorite retrogression of porphyroblasts occurs in sub-sillimanite grade rocks in the western part of the area. Synmetamorphic veins represent polyepisodic hydraulic fracture development during progressive dewatering of a sedimentary pile by prograde metamorphism.
Eastward obduction of Quesnellia and Slide Mountain Terranes onto theOmineca Belt took place in the Middle Jurassic. Shortly following this event, the IMB-OMB tectonic suture was deformed, forming map-scale folds of cuspate/lobate geometry.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
10
Lewis, Peter D. "Polyphase deformation and metamorphism in the western Cariboo Mountains near Ogden Park, British Columbia." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26440.
Full textAbstract:
The boundary between the Omineca Belt and the Intermontane Belt in Central British Columbia represents the suture between autochthonous North America (Barkerville Terrane) and several allochthonous terranes accreted from the west In the Quesnel Lake region allochthonous sedimentary and volcanic rocks of Quesnellia Terrane, accreted in the Jurassic, are in sharp tectonic contact with underlying siliclastic and carbonate metasedimentary rocks. The Ogden Peak study area is located 10 km east of and structurally below this suture zone and is thus well situated for observing deformational styles within the autochthonous package. Rocks exposed near Ogden Peak comprise the Hadrynian(?) to Paleozoic(?) Snowshoe Group and local diabasic intrusions. These rocks record a deformational history involving four phases of folding (D₁-D₄) and later brittle faulting (D₅). Earliest recognizable structures consist of recumbant isoclinal folds with a well-developed transposed foliation. This foliation is tightly folded about northwest trending, southwest verging second phase structures. Northwest trending third phase structures and northeast trending fourth phase structures occur as both crenulations and open buckles. Southeast dipping faults cut all earlier structures with tens of meters of normal offset
Phase 1 and Phase 2 fold styles are compatible with a flattened buckle fold mechanism of formation, associated with elevated temperatures and reduced viscosity contrasts across layering. Later fold styles are controlled by higher viscosity contrasts and detachment along layering.
All phases of deformation are dominated by semi-brittle mechanisms of dislocation slip and glide, mechanical twinning, and microcracking. Temperature activated diffusional creep is only locally active and does not contribute appreciably to total strain.
The mineral assemblage garnet-staurolite-kyanite defines a metamorphic peak late in D₂. Metamorphic temperatures of approximately 530° C at 6.0 kb have been determined using garnet/biotite geothermometry. Extensive retrograde metamorphism spans D₃ and D₄, overprinting prograde assemblages and providing evidence for abundant fluids late in deformation.
Late phase 1 diabase dykes locally intruded an area to the southeast of Ogden Peak. Major and trace element analyses of samples from these intrusions suggest a calc-alkaline, volcanic arc affinity.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
11
Driver, Leslie Ann. "Petrogenesis of the Cretaceous Cassiar batholith, Yukon-British Columbia, Canada, implications for magmatism in the North American cordilleran interior." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/MQ34353.pdf.
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12
Pearson, David M., Douglas R. MacLeod, Mihai N. Ducea, George E. Gehrels, and Patchett P. Jonathan. "Sediment underthrusting within a continental magmatic arc: Coast Mountains batholith, British Columbia." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626287.
Full textAbstract:
Though continental magmatic arcs are factories for new continental crust, a significant proportion of continental arc magmas are recycled from supracrustal material. To evaluate the relative contributions of retroarc underthrusting and trench side partial sediment subduction for introducing supracrustal rocks to the middle and lower crust of continental magmatic arcs, we present results from the deeply exposed country rocks of the Coast Mountains batholith of western British Columbia. Prior work demonstrates that these rocks underwent widespread partial melting that contributed to the Coast Mountains batholith. We utilize U-Pb zircon geochronology, Sm-Nd thermochronology, and field-based studies to document the protoliths and early burial history of amphibolite and granulite-facies metasedimentary rocks in the Central Gneiss Complex. U-Pb detrital zircon data from the structurally highest sample localities yielded similar to 190Ma unimodal age peaks and suggest that retroarc rocks of the Stikine terrane constitute a substantial portion of the Central Gneiss Complex. These supracrustal rocks underwent thrust-related burial and metamorphism at >25km depths prior to similar to 80Ma. These rocks may also be underlain at the deepest exposed structural levels by Upper Cretaceous metasedimentary rocks, which may have been emplaced as a result of trench side underplating or intraarc burial. These results further our understanding of the mechanisms of material transport within the continental lithosphere along Cordilleran subduction margins.
13
Owens, Philip Neil. "Lake sediment-based sediment yields and erosion rates in the Coast Mountains, British Columbia." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29695.
Full textAbstract:
Lake sediments have been identified as an alternative to contemporary stream monitoring to establish catchment sediment yields and infer erosion rates. This is due primarily to the longer time period over which the former is based, which makes established yields and rates more representative of means or trends in sedimentation. Studies using lake sediments to establish sediment yields have generally assumed that all the sediment contained within a lake is derived from erosion of the catchment under investigation. This study undermines this assumption by constructing a comprehensive lake sediment budget to asses the relative contributions from various sources. Late Holocene (the last 2350 years) rates of sediment yield and erosion are established for 3 small (<1 km²) catchments that straddle timberline (1620 - 1850 m above sea level) in the Coast Mountains of British Columbia.
Due to the temporal and spatial variability of sedimentation in lakes, sediment cores for each lake were taken using a multiple-core approach. Chronology was established by the presence of a dated tephra layer. Once the cores were extracted, corrections were made for sediment derived from aquatic productivity (organic matter and biogenic silica), regional aeolian dust input, the erosion of lake banks and for outflow losses. These sources of sediment could account for between 55 and 99% of the sediment contained within the 3 lakes. Lake trap efficiency ranges from low to >70%. Once corrected, estimates of sediment yield range from 4 and 244 kg km⁻²yr⁻¹. The rate of regional aeolian deposition indicates that, in certain areas, these catchments are undergoing net deposition and not net erosion. The implications for lake sediment-based sediment yields and erosion rates are examined. When placed in a regional context sediment yields are more than 1 order of magnitude lower than larger scale basins due to changes in sediment storage. The spatial and temporal representativeness of the data are also evaluated.Arts, Faculty of
Geography, Department of
Graduate
14
Souch, Catherine Jane. "Lake sediments as records of palaeoenvironmental change : Kwoiek Creek, Coast Mountains, British Columbia." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30833.
Full textAbstract:
It has been suggested that the dominant controls on alpine sediment transfers during the Holocene Epoch relate to climate change, specifically paraglacial sedimentation and Neoglacial activity. Alpine lakes with appropriate geometry and hydraulic conditions trap a high proportion of sediments inflowing from their surrounding drainage basins. Thus alpine lake sediments have the potential to yield a comprehensive, integrated signal of drainage-basin geomorphic activity through time, which may be interpreted as a proxy record of Neoglacial activity.
This study is concerned with the interpretation of alpine lake sediments in glacierized drainage basins as records of Neoglacial activity. It adopts an explicitly geomorphological approach that integrates an understanding
of the drainage basin sedimentary system, specifically sediment sources and transfers, with the interpretation of lake sediment deposits and extends existing models of alpine sedimentary response down-valley, away from the immediate proglacial environment.
A down-valley sequence of four valley bottom lakes, Kha, Klept, Kokwaskey and Kwoiek, within the Kwoiek Creek watershed, southeastern Coast Mountains of British Columbia, were studied. Sub-bottom sounding and multiple cores from each lake allowed identification of lake-wide changes in sediment input through time; in addition terrain mapping and characterisation
of sediment sources provided a framework within which to identify the sources of the lake sediments and their fluctuations through time.
Preliminary characterization of the sediments broadly separated organic and clastic components. Detailed laboratory analyses revealed organic matter content to be a good inverse indicator of sedimentation rates. Grain size analyses revealed three distinct textural populations.
Graphical partitioning of the cumulative grain size distributions identified each fraction for further analysis. The provenance of the coarsest and intermediate fraction was determined through SEM surface texture analysis of a statistically representative number of grains. The coarsest fraction was derived from localized colluvial sources. The intermediate fraction was derived from glacial sources and strongly filtered downsystem. The finest fraction was characterised as glacial in origin because of consistent trends in its variability at the drainage basin scale through time. Fluctuations in the total influx of the intermediate and finest fractions are interpreted as a proxy record of Neoglacial activity in the watershed. Analysis of persistence in the sedimentation data indicates history of the order 100 yrs, which is interpreted as an index of the relaxation time of sedimentary stores.
Basal dates on the sediments provide the earliest dates for deglaciation in the southern Coast Mountains, suggesting that extensive areas of southwestern British Columbia were ice free prior to 11 500 B.P. Three phases of Neoglacial activity centred 6000 to 5000 B.P., 3500 to 2900 B.P. and post 750 B.P are suggested by increased sedimentation rates for glacially-derived material. When compared with reconstructions from a pollen study conducted within the watershed and regional chronologies reported in the literature, there is remarkable consistency.
The major advantage of the lake sediment approach as developed in this study is the continuity and apparent sensitivity of the derived proxy records. These records permit a consideration of both the magnitude and frequency of palaeoenvironmental change, specifically Neoglacial activity, at one site. Such a record has not been found elsewhere in British Columbia, where discontinuous terrestrial records have been used.Arts, Faculty of
Geography, Department of
Graduate
15
Fillipone, Jeffrey Alan. "Structure and metamorphism at the western margin of the Omineca belt near Boss mountain, east central British Columbia." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24661.
Full textAbstract:
Rocks of the Hadrynian and Early Paleozoic (?) Snowshoe Group comprise the core of the Boss Mountain area at the western margin of the Omineca Belt near Crooked Lake. Structurally overlying these are rocks of the Intermontane Belt: the Permian Slide Mountain Group (Antler Formation), Triassic fine grained sediments (unnamed), and Jurassic volcanic rocks (Takla Group). In the Snowshoe Group, a large, lensoid intrusion of coarse grained granitic rock (Boss Mountain gneiss) was emplaced during the mid-Paleozoic, and later deformed and metamorphosed with the enclosing metasediments.
The rocks of the Snowshoe Group act as basement to the overlying Late Paleozoic/Early Mesozoic cover rocks. Within the basement, four phases of regionally significant deformation have been recognized, and are manifest as fold generations designated Fl through F4.
Earliest structures, Fl, in the Snowshoe Group are isoclinal folds, accompanied by a transposed foliation of regional extent, which are overprinted by penetrative deformation related to easterly verging F2 nappe structures. The F3 folds are upright or inclined to the northeast, and give a consistent southwesterly sense of vergence. These folds are responsible for the regional map pattern, and have folded both the basement and cover into an antiformal culmination in the Boss Mountain area. Fourth phase structures refold the other features, but do not appreciably affect the F3 geometry.
In the cover sequences, the first phase of deformation is equivalent to the second phase within the basement During the Phase 2 deformational episode the cover rocks were emplaced over rocks of the Snowshoe Group. West-dipping imbricate faults characterize the western margin of the area, where basement rocks contain fault-bounded slivers of the cover, and the tectonic contact between basement and cover rocks is marked by a zone of mylonitization. Similarly, the F2 and F3 folding phases in the cover are equivalent to the F3 and F4 structures in the basement, respectively, but are only weakly developed in the cover.
An early, enigmatic metamorphic event accompanied Phase 1 deformation in rocks of the Snowshoe Group. Field relations suggest that this was probably coeval with the mid-Paleozoic emplacement of the Boss Mountain gneiss. Metamorphism during the Jurassic was synchronous with F2 deformation in rocks of the Snowshoe Group, and resulted in Barrovian type mineral assemblages ranging from the biotite through sillimanite zones. The metamorphic grade increases from west to east; with only low grade metamorphism of the cover rocks in the study area. Phase 2 structures in the Snowshoe Group were overprinted by the peak of this metamorphic event, as indicated by staurolite through sillimanite zone assemblages.
The Boss Mountain area is structurally correlative with rocks of the Shuswap Complex. These rocks appear to comprise a portion of the continental margin sedimentary wedge, which was overridden by an allochthonous terrane accreted to the western margin of North America in post-Early Jurassic times.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
16
Demerse, Deirdre K. "Sinsistral high strain in the Coast Mountains near Bella Coola, West Central British Columbia." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2465.
Full textAbstract:
The Bella Coola area geographically straddles two zones of known Early to mid-Cretaceous sinistral ductile strain; the Grenville, Kitkatla, and Principe-Laredo shear zones to the northwest located near Prince Rupert, B.C., and the Tchaikazan fault system to the southeast. At the latitude of Bella Coola in west-central B.C., the Pootlass High Strain Zone (PHSZ) is a ductile, subvertical, shear zone system at least 2 km wide and at least 30 km long. The purpose of this study is to determine the age, kinematics, and tectonic significance of the PHSZ, and to investigate whether or not it was active as a kinematic link to Early to mid-Cretaceous sinistral ductile strain zones in the western Canadian Cordillera. This thesis reports recent observations from field mapping and new geochronological, microstructural, and petrological data, from which the PHSZ is characterized and placed into a regional tectonic framework.
U-Pb and 40Ar/39Ar isotopic geochronology indicate that regionally extensive, southwest-vergent folding in the PHSZ area was active prior to 114 Ma and persisted until at least 73 Ma. High-temperature, ductile, sinistral non-coaxial strain in the PHSZ was accommodated between 76 (or earlier) and 62 Ma. Localization of high strain is associated with the emplacement of plutonic rock and abundant intrusive sills, which likely acted as a strain-softening mechanism. L-tectonites within the deformed plutonic rocks attest to the weakness of the rocks during deformation and support syn-kinematic magmatism. Geothermometric and petrological data suggest that deformation occurred at temperatures of 537 to 731°C and at crustal depths of —23 km.
The PHSZ is interpreted to be kinematically related to the Talchako Fault to the east, which was active as a sinistral mylonitic shear zone between 70 and 65 Ma. A kinematic relationship between the PHSZ and the Grenville, Kitkatla and Principe-Laredo shear zones near Prince Rupert imply a protracted history of sinistral transpression in the Coast Mountains of British Columbia that persisted in the Bella Coola region through Late Cretaceous time.
17
Montgomery, John R. "Structural relations of the southern Quesnel Lake gneiss, Isosceles mountain area, southwest Cariboo mountains, British Columbia." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24868.
Full textAbstract:
The southern extension of the Quesnel Lake Gneiss lies approximately 10 km northeast of the Intermontane-Omineca Belt tectonic contact in the southwestern Cariboo Mountains, British Columbia. The aim of this thesis is the investigation of the structural development and style at a deep structural level relative to the 1MB-OB contact, and to determine the nature origin of the southern extension of the Quesnel Lake Gneiss. Omineca Belt rocks in the Quesnel Lake region are the Late Proterozoic to Late Paleozoic Snowshoe Group metasediments. The Snowshoe Group rocks in this study area comprise a package of variably micaceous schist, quartz-biotite gneissose schist, calcareous metasandstone, marble and amphibolite which represent deformed and metamorphosed continental margin deposits. The Quesnel Lake Gneiss is a predominately subalkaline granodioritic intrusive into these sediments that has been modified by subsequent deformation and metamorphism. High Sr content, low initial ⁸⁷Sr/⁸⁶Sr ratios and an alkalic component imply a mantle source although possible Pb inheritance in zircons and regional Sr data suggest a certain amount of assimilated continental crust A U-Pb zircon age on the Quesnel Lake Gneiss indicates intrusion in Mid-Paleozoic, probably Devonc—Mississippian time. A regional metamorphic event affecting the entire sedimentary and intrusive package is interpreted to have occurred in the Middle-Jurassic as suggested by sphene U-Pb geochronometry and regional stratigraphic relations.
The structural sequence observed in this area is composed of five phases of folding followed by a brittle fracturing and faulting phase. The entire sequence of deformation is seen in both the Snowshoe Group and the Quesnel Lake Gneiss. A pervasive metamorphic foliation defines the compositional layering (S0/1) and is axial planar to isoclinal first phase folds in both rock packages. Syn-metamorphic second phase deformation is evidenced as tight similar-style folds with an axial surface penetratively developed at a low angle (10-15°) to the compositional layering. Syn- to post-metamorphic third phase deformation produced southwest verging folds with only locally penetrative axial surfaces developed at approximately 40° to SO/1 compositional layering and northwest plunging fold axes nearly coaxial with F2 folds. The Quesnel Lake Gneiss shows a lack of F3 macroscopic folds. Fourth and fifth phase folds are brittle, broad warps that are only locally developed in the more micaceous units. A series of ť vs. α plots on second and third phase folds in both rock types indicates a ductile regime associated with high shear strain during F2 deformation with decreasing shear strain and less ductile behavior during the third phase of deformation. This change in behavior corresponds with the waning of metamorphism.
At least one regional metamorphic episode has affected this area in association with the deformational sequence outlined above. The metamorphic peak occurs post-F2 and pre- to syn-F3 deformation producing Barrovian-type assemblages of the amphibolite facies. Metamorphic temperatures of approximately 590° C at 5.5 kb were determined by garnet-biotite geothermometry in sillimanite-bearing schists northeast of the Quesnel Lake Gneiss.
A tectonic history for the rocks in this map area began with the deposition of the Snowshoe Group sediments in a continent margin basin from the Late Proterozoic to the Early Mississippian. Intrusion into this package by the Quesnel Lake granitic body occurred between 317 and 400 Ma ago. The first phase of deformation recognized in the Snowshoe Group and Quesnel Lake Gneiss is absent in the Quesnellia and Slide Mountain rocks and may also be of Paleozoic age. The accretion of Quesnellia onto the continental margin in Early Jurassic time is inferred to have initiated the subsequent deformation and regional metamorphism.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Smith, Michael J. "Postglacial changes in chironomid communities and inferred climate near treeline at Mount Stoyoma, Cascade Mountains, southwestern British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24242.pdf.
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Moertle, Jasmine A. "Stable isotope evidence for a complex fluid evolution of the Northwestern British Columbia Coast Mountains related to terrane accretion." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10147322.
Full textAbstract:
Stable isotope analysis of thirty-five samples from the Northwestern Coast Mountains indicates a complex fluid history related to terrane accretion, metamorphism, and magmatism. The greenschist to amphibolite facies metasedimentary rocks from the Western Metamorphic Belt have variable δD and δ 18O values that appear to be in isotopic equilibrium with metamorphic fluids at low water-rock ratio conditions. Carbon isotope values indicate organic rich protoliths. Stable isotope values from the Coast Shear Zone indicate the involvement of both magmatic and meteoric-hydrothermal fluids during deformation, in contrast to meteoric-free fluid systems related to Au-mineralization along strike to the north (Goldfarb et al., 1988). The Coast Mountain Batholith and Central Gneiss Complex have homogeneous δD and δ 18O values that indicate magmatic fluids at low water-rock ratio (Magaritz and Taylor, 1976). Further to the east, large amounts of meteoric-hydrothermal fluids circulated through a network of ductile-to-brittle normal faults (Andronicos et al., 2003; Heah, 1990).
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Radloff, Judith Katherine. "Origin and obduction of the ophiolitic Redfern Complex on the Omineca-Intermontane Belts boundary, western Cariboo Mountains, British Columbia." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/27621.
Full textAbstract:
The Redfern Complex is a klippe of a dismembered, metamorphosed ophiolite resting on top of the crystalline Snowshoe Group in east-central British Columbia. The Snowshoe Group belongs to the Barkerville terrane of the Omineca Crystalline Belt while the Redfern Complex, which is structurally overlain by the Triassic black phyllite, comprises the basement to Quesnel terrane rocks of the Intermontane Belt. The contiguous boundary between the two belts lies west of the Redfern Complex and is marked by the Crooked Amphibolite, a thin, highly sheared mafic amphibolite with blocks of ultramafic rock near its base.
The Redfern Complex and Crooked Amphibolite are correlative assemblages evidenced by similiarities in lithology, whole rock and mineral chemistry, and structural position. Both assemblages are composed of variable amounts of hornblende-epidote-palgioclase amphibolite, dunites, cumulate layered peridotite, and serpentinite. Chemically the rocks are subalkaline, tholeiitic basalts or gabbros and depleted peridotite with relict forsteritic olivine (Fo₈₃ and Fo[sub 87-90.7]), chromian diopside, and chromite spinel. Ultramafic rocks from both assemblages show evidence of plastic deformation under mantle conditions including disolcation glide on the high temperature (010): [100] slip system and glide climb in olivine, plus dynamic recrystallization and dynamic recovery. Although the structural succession of lithologies is best defined at the locality of the Redfern Complex, variably complete structural successions across the Crooked Amphibolite were observed which indicate that the two units occupy the same structural position on top of the Hadrynian to Paleozoic metasedimentary Snowshoe Group and that both units are structurally overlain by the Triassic black phyllite. The two assemblages differ in intensity of metamorphism and degree of hydration alteration related to their relative structural positions and their size and permiability. While the Crooked Amphibolite bears the chlorite-zone assemblage actinolite + chlorite + plagioclase and related ultramafic rocks are dominantly completely serpentinized, the Redfern amphibolite metamorphic assemblage of hornblende + albite + epidote belongs to the albite-epidote amphibolite facies. In addition the large, coherent Redfern peridotite body shows evidence of complete serpentinization only at its margins and also bears an amphibolite facies assemblage of tremolite + olivine + chlorite + talc. Thus the Redfern Complex experienced more intense metamorphism because it occupied a deeper structural level than the Crooked Amphibolite.
The local and regional setting of the Redfern Complex reflects a complex geologic history of multiple defomration episodes and syntectonic, locally intense metamorphism related to the emplacement of the Complex onto the Snowshoe Group along the east-vergent Redfern thrust. Prior to emplecement, the Snowshoe Group underwent one enigmatic phase of deformation and metamorphism. The intrusion of the felsic Redfern orthogneiss which has a poorly constrained U-Pb age of Devono-Mississippian may be related to this deformation. A second orthogneiss which intrudes the Redfern amphibolite and contains ultramafic xenoliths probably intruded during or soon after emplacement. Tight, east-vergent folds and a pervasive second foliation developed in the Snowshoe Group while tight folds and a pervasive foliation developed in the Redfern amphibolite and Triassic black phyllite during emplacement. Microfracturing and grain sliding predominantly on the margins of the Redfern peridotite are the only structures developed during emplacement. Metamorphism peaked after emplacement stresses had relaxed, producing sillimanite in the Snowshoe metapelites, albite-epidote amphibolite assemblages in mafic lithologies, and possibly only kyanite in the black phyllites. Post-emplacement deformation accompanied sustained but decreased temperatures of metamorphism. Large-scale, west-vergent, overturned to the east buckles fold the Redfern thrust and refold earlier structures and produced the current map patterns and distribution of foliation. Kinked metamorphic porphyroblasts and an S₂ crenulation cleavage overgrown by staurolite in the Triassic black phyllite indicate that intense deformation and fluid enhanced retrograde metamorphic reactions were localised in a structurally lower "pocket" of this unit in the core of a post-emplacement synform on the east side of the map area.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Kaylor, Donald Charles. "Facies and diagenesis of the upper Devonian Palliser formation, front ranges of the Southern Rocky Mountains, Alberta and British Columbia." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64029.
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Cooley, Michael Ames. "Closely spaced metamorphic isograds along the Matthew Fault, Cariboo Mountains, British Columbia, relationships between metamorphism and dextral strike-slip faulting." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq20618.pdf.
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Warren, Marian Jenner. "Crustal extension and subsequent crustal thickening along the Cordilleran rifted margin of ancestral North America, western Purcell Mountains, southeastern British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22501.pdf.
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Franck, Ian Christian. "An archaeological investigation of the Galene Lakes area in the Skagit Range of the North Cascade Mountains, Skagit Valley Park, British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0026/MQ51342.pdf.
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Murphy, Donald Currie Carleton University Dissertation Geology. "Stratigraphy and structure of the east-central Cariboo Mountains, British Columbia and implications for the geological evolution of the southeastern Canadian Cordillera." Ottawa, 1985.
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Stoddart, Mark Christopher John. "Making meaning out of mountains : skiing, the environment and eco-politics." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/934.
Full textAbstract:
This research provides a sociological analysis of skiing as a form of outdoor recreation and nature tourism in British Columbia, Canada. A qualitative multi-method approach is used, combining discourse analysis, interviews with skiers, and unobtrusive field observation at Whistler Blackcomb and Whitewater ski resorts. Through a focus on discourse, embodied interactions among humans and non-humans, and flows of power, this research describes an environmental ambiguity at the centre of skiing. There is a tension between interpretations of skiing as an environmentally-sustainable practice and notions of skiing as an environmental and social problem. Skiing is based on the symbolic consumption of nature and is understood by many participants as a way of entering into a meaningful relationship with the non-human environment. However, interpretations of skiing as a non-consumptive use of non-human nature are too simple. Social movement groups disrupt pro-environmental discourses of skiing by challenging the sport’s ecological and social legitimacy. Many skiers also articulate a self-reflexive environmental critique of their sport. In these instances, skiing is brought into the realm of politics. Recreational forms of interaction with the non-human environment tend to be at the periphery of environmental sociology. At the same time, sport sociologists tend to focus on the social dimensions of outdoor recreation, while bracketing out non-human nature. This research brings these two fields of inquiry into dialogue with each other, thereby addressing this double lacuna.
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Ramcharita, Roger Karim. "Grizzly bear use of avalanche chutes in the Columbia Mountains, British Columbia." Thesis, 2000. http://hdl.handle.net/2429/11464.
Full textAbstract:
I examined spring season use of avalanche chutes by grizzly bears (Ursus arctos
L.) in the Columbia Mountains, southeastern British Columbia. Sixty radio-collared
grizzly bears were monitored between 1994 and 1998. The frequency of avalanche chute
use, the selection of general habitat characteristics within avalanche chutes, and the
selection of specific feeding and bedding sites within avalanche chutes by grizzly bears
were documented.
Fifty-four percent (366/672) of all grizzly bear radio-locations during the spring
season (May 1 to July 31) were in avalanche chutes. The proportion of radio-locations in
avalanche chutes for the 37 grizzly bears that accounted for > 10 spring season radiolocations
each ranged between 20% and 90% (x = 56% ± 18% [mean ± SD]). This
variation was not attributable to differences in use between sex or age classes.
Within avalanche chutes, grizzly bears selected east and south aspects and areas
dominated by grasses and forbs with minimal shrub abundance. Grizzly bears avoided
very steep slopes but used all elevational parts of avalanche chutes - upper start zones,
tracks, and lower runout zones. These patterns appeared to be tied to feeding site
selection, because evidence of feeding was found at most telemetry locations investigated
on the ground.
Grizzly bears selected feeding sites on the basis of forage value and visual cover.
Most feeding sites were characterized by high forage value and low visual cover, but
weak positive interaction between these two factors indicated that grizzly bears also
selected feeding sites with slightly lower forage values but high visual cover. Bed sites
were found both in forest adjacent to avalanche chutes and directly within avalanche
chutes. All bed sites found in forests adjacent to avalanche chutes were < 25 m from the
forest / avalanche chute edge.
The impact on grizzly bear use of avalanche chutes by two timber harvest
activities was also examined. Grizzly bears avoided areas within avalanche chutes that
were adjacent to cutblocks, possibly due to the removal of escape cover. In contrast,
grizzly bears selected areas close to logging roads. Most logging roads traversing
avalanche chutes in the study area had minimal vehicle traffic and were often situated
close to areas with abundant food resources. I present suggestions for managing this
important spring season habitat for grizzly bears.
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Evans, Martin Grant. "Neoglacial climate in the Southern Coast Mountains, British Columbia." Thesis, 1993. http://hdl.handle.net/2429/1238.
Full textAbstract:
Palaeobotanical records of Holocene climate change in the southern Coast Mountains identify a cooler/wetter Neoglacial period subsequent to 6600 BP. Geomorphic evidence of alpine glacier advance suggests that there were three distinct cooler/wetter periods during the Neoglacial, but this pattern has not been identified in palaeobotanical studies. By careful selection of a sensitive alpine site this thesis has recognised this structure in a palynological record of Neoglacial climate. This continuous record of Neoglacial climate which has the same basis as records of early Holocene climate (i.e. palynological) and hence allows more direct comparisons of the two periods. Pollen spectra, conifer needle macrofossils, organic matter content, and magnetic susceptibility were assessed for a 4800 year continuous sequence of sediment from an alpine lake. Calibration of the Picea/Pinus pollen ratio by using an altitudinal transect of surface pollen samples allowed partial quantification of shifts in treeline. Treeline at the site was at least 85 m above the present level from 4800-3800 BP, suggesting that summer temperatures were at least 0.6°C above the present. High treeline until 3800 BP indicates a relatively late date for the Hypsithermal/Neoglacial transition at this site. Alternatively, the apparent complexity of this transition in the Coast Mountains may be due to difficulties of separating temperature and precipitation signals in many climatic records. Treeline declined to near present levels by 2500 BP and was lower than present from 2500-1500 BP and from 1200 BP until close to the present. Estimates of equilibrium line altitude depression for Coast Mountain glaciers during the Little Ice Age suggest that these periods of lower treeline were due to a cooling of up to 0.8°C. During the last 5000 years the Southern Coast Mountains have experienced fluctuations on the order of 1.5°C.
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Menounos, Brian Peter. "Climate, fine-sediment transport linkages, Coast Mountains, British Columbia." Thesis, 2002. http://hdl.handle.net/2429/12785.
Full textAbstract:
The relation between climate and sediment yield remains poorly defined in regions of high relief and
where sediment sources are numerous. This study examines the climatic controls associated with
fine sediment production and yield for six glacierized watersheds in the Coast Mountains, British
Columbia, Canada. Contemporary monitoring of suspended sediment transport was undertaken
to detail the hydrologic conditions responsible for the entrainment and production of fine-grained
sediment production and transport. The analysis of lake sediments recovered from outlet lake
basins provided a means of documenting changes in sediment delivery over century to millennia
time scales. Four of the lake basins contain finely laminated sediments which are interpreted to be
clastic varves and so detail lake sedimentation at annual to event time scales.
The results indicate that much of the variance in sediment transport records can be attributed
to hydro-climatic variability at all time scales under consideration and much like other geophysical
time series, a 1/frequency-variance scaling is apparent within the yield proxies of this study. Climatological
conditions important for sediment production and entrainment at event to annual scales
include those processes responsible for high flow events in the study area. Decadal-scale variations
in sediment delivery coincide with sustained periods of ice melt. Sediment delivery from the watersheds
at century to millennial time scales reflects major changes in ice cover. The correspondence
between long records of lake sedimentation and air-temperature proxies developed from tree rings
and ice cores suggests that changes in sediment yield from the watersheds reflects changes in air
temperatures in the study area. Variations in air temperature appear to influence sediment transfers
by controlling the intensity of glacial runoff during the ablation season. Highest sensitivity (i.e.
those records where geomorphic filtering of the climate signal has not occurred) is noted for those
basins which have active glaciers and the opportunity for sediment storage of fine-grained sediment
in the fluvial system is low.
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Horner, Graham. "Mountains of money : the corporate production of Whistler resort." Thesis, 2000. http://hdl.handle.net/2429/10636.
Full textAbstract:
The aim of this thesis is two-fold. My primary, theoretical aim is to present an alternative
way for geographers to approach the study of tourist resort development. For over twenty
years, resorts have been understood through the framework of evolutionary models, the
most widely-used being Richard Butler's 1981 Tourist Area Life Cycle. I argue that the
time is ripe for a more sophisticated approach which i) identifies the multiplicity of actors
involved in the destination-making process and elucidates the interactions between them;
and ii) situates the resort within a dynamic, capitalist economy, increasingly dominated by
large corporations. I suggest that one way we can do this is to take particular moments in
a resort's trajectory and examine the responses made by key players in the production of
the resort.
My starting point for my investigation into Whistler Resort, British Columbia is the
merger in 1996 of its two ski mountains, Whistler and Blackcomb, under the ownership
of Intrawest Corporation. A recent wave of consolidation in the North American ski
industry has seen increasing numbers of once-independent ski areas coming under the
control of four large corporations, Intrawest being one. My second aim with this thesis,
therefore, is to shed light on the process of ski resort development in light of the recent
industry reorganisation. In particular, I use my case-study of Whistler to interrogate the
corporatisation thesis of historian Hal Rothrnan. Rothman's account of resort
development in the twentieth-century American West leads him to view large
corporations as extractive forces which pay scant respect to local communities and
cultures, treating them instead as marketable commodities. The experience of Whistler,
however, suggests a much greater degree of mterdependence and co-operation between
the ski corporation and local stakeholders in the resort - a situation that arises because of
its unique administrative, political and economic context.
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Harvey, Jillian Elizabeth. "Holocene glacier activity in the central British Columbia Coast Mountains." Thesis, 2011. http://hdl.handle.net/1828/3473.
Full textAbstract:
The intent of the research described in this thesis was to reconstruct and document Holocene glacier activity in the central British Columbia Coast Mountains. Despite ongoing efforts to describe glacier fluctuations in the southern and northern Coast Mountains, only limited attention has been directed to revealing the Holocene histories of glaciers in the central Coast Mountain region. The goals of this research were twofold: firstly, to describe mid-Holocene glacier advances at five remote glacier sites in the central Coast Mountains, and secondly, to detail Little Ice Age (LIA) glacier fluctuations at four glacier sites in the central Coast Mountains.
The mid-Holocene behaviour of Canoe, Fyles, Jacobsen, Tchaikazan and Icemaker glaciers was investigated using dendroglaciological techniques and stratigraphic analysis. Subfossil wood evidence suggests these glaciers were expanding into standing forests prior to 6.63, 4.90 and 4.20 ka. Stratigraphically constrained woody detritus at Fyles Glacier records the progradational history of a Gilbert-type delta forming in response to glacial expansion between 7.02-5.47 ka. Glacial expansion occurring between 7.50-4.00 ka has regional correlatives, suggesting coherent broad-scale climate forcing mechanisms influenced glacial mass balance at this time.
Insight into the LIA behaviour of central Coast Mountain glaciers was provided by conducting lichenometric surveys of Rhizocarpon spp. across LIA moraines at Pattullo, Fyles, Deer Lake and Jacobsen glaciers. The presence of a second, lesser known, lichen species at some sites necessitated the construction of a Xanthoria elegans growth curve. An assessment of lichenometric measurements from the southern and central Coast Mountains provided the opportunity to build a X. elegans growth curve constrained by 18 control points. Lichenometric surveys revealed dominant moraine building episodes at 890-1020, 1280-1320, 1490-1530, 1680-1720, 1780 and 1820-1870 AD, highlighting the complex nature of glacier fluctuations during the LIA.
A regional subalpine fir tree-ring chronology (1610-2010 AD) was developed from four stands located in the central Coast Mountains for dendroclimatological investigations. Correlation analyses show that the radial growth of trees corresponded to variations in the mean June/July air temperature and May 1st snowpack. This relationship was used to reconstruct these climate parameters for the duration of the tree-ring record. Intervals of cooler summer air temperatures and above average snowpack were found to broadly correspond with dominant periods of LIA moraine building from 1610-1930 AD.
This reconstruction of mid-Holocene and LIA glacial history offered insights consistent with the emerging record of glacial activity described for the southern Coast Mountain glaciers. It also provides the first evidence for mid-Holocene glacial expansion in the central and northern Coast Mountains. The application of lichenometry in the central Coast Mountains documents the regional LIA behaviour of glaciers and the construction of a Xanthoria elegans growth curve for the Coast Mountains provides a framework for future geobotanical dating using this species.Graduate
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Waddington, Betsy Anne. "The Fraser Glaciation in the Cascade Mountains, southwestern British Columbia." Thesis, 1995. http://hdl.handle.net/2429/3680.
Full textAbstract:
The objective of this study is to reconstruct the history of
glaciation from the start of Fraser (Late Wisconsinan)
Glaciation to the end of deglaciation, for three areas in the
Cascade Mountains. The Cascade Mountains are located between
the Coast Mountains and the Interior Plateau in southwestern
British Columbia. The Coast Mountains were glaciated by
mountain glaciation followed by frontal retreat, whereas the
Interior Plateau underwent ice sheet glaciation followed by
downwasting and stagnation. The Cascades were supposed to have
undergone a style of glaciation transitional between these
two.
Terrain mapping on air photographs followed by field checking
was used to locate surficial materials and landforms
indicative of glaciation style and pattern. All three study
areas were glaciated by mixed mountain and ice sheet
glaciation. At the start of Fraser Glaciation, alpine and
valley glaciers formed around higher summits as occurred in
the Coast Mountains. At the glacial maximum the entire area
was covered by the Cordilleran Ice Sheet. Deglaciation was
largely by continuous downvalley retreat of active glaciers,
contrasting with downwasting and stagnation in the Interior
Plateau, and frontal retreat in the Coast Mountains. The
scarcity of fresh moraines in the cirques suggests that,
unlike in the Coast Mountains, most cirque glaciers were not
active at the end of glaciation. Only the highest north facing
cirques remained above the local snowline throughout
deglaciation and, as a result, glaciers in these valleys
remained active and retreated up valley.
The pattern of glaciation in the Cascade Mountains was similar
to that of other areas which underwent mixed mountain and ice
sheet glaciation, such as the Presidential Range in New
Hampshire, the Green Mountains in Vermont, mountain ranges in
west central Maine and the Insular Mountains on Vancouver
Island. However, deglaciation in al l areas was complex and
depended strongly on local conditions. For this reason local
patterns cannot be predicted easily on the basis of glaciation
style.
The value of an understanding of glaciation style to improve
the accuracy of terrain mapping was also investigated. It was
found that the model developed for the Cascade Mountains was
of some use in predicting the presence of fine-textured
material in valley bottoms and for the prediction of
glaciofluvial material overlying till . However fine-textured
sediments were not found in al l valleys which were predicted
to contain them. The model appears to be most useful as an
indicator of where to concentrate field checking in order to
locate fine-textured sediments.
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Laxton, Sarah Coulter. "Dendroglaciological reconstruction of late Holocene glacier activity at Todd Glacier, Boundary Range, northwestern British Columbia coast mountains." 2005. http://hdl.handle.net/1828/829.
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Allen, Sandra Michele. "Late Holocene glacial activity of Bridge Glacier, British Columbia coast mountains." Thesis, 2006. http://hdl.handle.net/1828/2259.
Full textAbstract:
Bridge Glacier is a prominent eastward-flowing valley glacier located on the east side of the Pacific Ranges within the southern British Columbia Coast Mountains. The terminus of Bridge Glacier has retreated at rates ranging from 0 to 125 m/year over the last 50 years and currently calves into proglacial Bridge Lake. Field investigations of the recently deglaciated terrain at Bridge Glacier in 2002 and 2003 led to the discovery of detrital boles and glacially-sheared stumps. Dendroglaciological analyses of this subfossil wood allowed for the construction of five radiocarbon-controlled floating tree-ring chronologies. The relative age and stratigraphic location of these samples revealed that Bridge Glacier experienced at least four periods of significant advance during the late Holocene: a Tiedemann-aged advance at ca. 3000'4C years BP. an unattributed advance at ca. 1900 '4C years BP. a First Millennial Advance at ca. 1500 '4C years BP. and an early Little Ice Age advance at ca. 700 '4C years BP. Lichenometric investigations at eight terminal and lateral moraine complexes led to the recognition of early Little Ice Age moraine-building events during the late 13th to early 14th centuries. with subsequent Little Ice Age episodes in the mid 15th. early 16th. mid-late 17th, early 18th, mid-late 19th, and early 20th centuries. These interpretations provide an exceptional long-term perspective on the extent and character of a glacier within this region during the late Holocene.
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Flower, Aquila. "A dendroclimatic investigation in the northern Canadian Rocky Mountains, British Columbia." Thesis, 2008. http://hdl.handle.net/1828/1398.
Full textAbstract:
Subalpine fir (Abies lasiocarpa [Hooker] Nuttall) and white spruce (Picea glauca [Moench] Voss) trees were sampled in an old growth forest in the northern Canadian Rocky Mountains. Dendroclimatological methods were used to analyse the relationship between annual radial-growth and climatic variability. The white spruce ring-width chronology showed stronger sensitivity to climatic variability than the subalpine fir chronology. Both chronologies were positively correlated with growing season mean and minimum temperature. Additionally, the white spruce chronology was correlated with summer maximum temperature, late spring minimum temperature, and diurnal temperature range during the growing season. The subalpine fir ring-width chronology was also correlated with maximum and minimum temperature and diurnal temperature range during the during the previous winter and with the Pacific Decadal Oscillation during each month from December to June. Analysis of the climate-growth responses of individual trees revealed a higher level of intraspecies variability in subalpine fir than in white spruce.
The white spruce chronology was selected for use in creating a proxy climate record based on its greater length and stronger sensitivity to climatic variability. Dendroclimatological methods were used to create a regional proxy record of June-July mean temperature extending back to 1772. This reconstruction exhibits a shared pattern of low-frequency variability with other dendroclimatic reconstructions from western Canada and shows no evidence of the recent reduction in sensitivity to climatic variability that is apparent in many other northern spruce chronologies.
This study represents the first detailed dendroclimatic analysis undertaken in northern interior British Columbia. This work has elucidated the complex interactions between climate and the radial growth of alpine conifers in the northern Canadian Rocky Mountains. The climate reconstruction presented here fills in one of the remaining spatial gaps in the coverage of annually resolved climate reconstructions in western North America.
36
Clarke, Jennifer A. "Snow glide and full-depth avalanche occurrence, Cascade Mountains, British Columbia." Thesis, 1994. http://hdl.handle.net/2429/3411.
Full textAbstract:
Snow glide is the translational slip of the entire snow pack over a sloping ground surface. It is
thought that rapid rates of snow glide precede the release of full-depth avalanches. The nature
of avalanches that release at the ground makes them difficult to predict and difficult to control
using explosives. The aim of this research is to determine the relationship between rapid snow
glide and full-depth avalanche occurrence and to examine climate factors affecting both
processes. Data collected from an instrumented site along the Coquihalla Highway in the
Cascade Mountains of British Columbia were used for analysis during two winter seasons (1992-93, 1993-94).
Glide is influenced by the nature of the interaction between the roughness of the ground and the
snow pack, and by the distribution of water at the interface. The presence of water at the
interface affects the material properties of snow and the friction conditions. The impact of freewater
on glide is influenced by the volume and rates of water input. Higher glide rates and fulldepth
avalanche release are the almost immediate responses to contributions of free-water. The
data show that the most significant contributor is rainfall, which is common in the study area
throughout the winter season. The supply of free-water from snow melt due to radiative and
thermal sources of energy become more significant in the spring.
Water inputs increase the thickness of the saturated layer at the base of the snow pack, allowing
greater amplitudes of roughness to be overcome. By drowning or partially drowning the
roughness elements, a thin film of water reduces the shear resistance of the snow pack to
downslope movement. Inputs of water at rates higher than transmissions rates will increase pore
pressures and decrease shear stress encouraging further downslope movement. Failure of the
snow pack at the ground is translational, most often occurring 12-24 hours after a rainfall event,
but sometimes much later when avalanche release would not be expected.
Although there is no threshold glide velocity associated with avalanche release, it can be
concluded that snow glide is a good indicator of active periods of full-depth avalanche
occurrence. However, results from this study show that rainfall rates and snow melt rates may
be more accurate predictors of avalanche occurrence in the study area.
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Schiefer, Erik Karl. "Contemporary sedimentation patterns within Green Lake, southern Coast Mountains, British Columbia." Thesis, 2004. http://hdl.handle.net/2429/17217.
Full textAbstract:
Lacustrine sediments have provided important information on historical sediment transfer processes and past environmental conditions for lake catchment systems over a wide range of temporal scales. In this study, contemporary patterns of lacustrine sedimentation are described and interpreted for Green Lake, a geomorphically active and morphologically complex lake catchment system in the southern Coast Mountains of British Columbia. Emphasis is placed on detailing spatial variability and characterizing stratigraphic signatures associated with major sediment delivery events. Identified trends in the sedimentary record are related to internal and external lake catchment process domains and physical controls. The research program has included a combination of intensive lake sediment coring, laboratory-based sediment analysis, detailed reconstructions of lacustrine sediment deposition, and case studies of the most significant sediment delivery events of the last 70 years. All bulk physical properties investigated exhibit a dominant monotonic pattern of variation from the principal lake inflow to more distal lake settings. An influence of water depth is observed only in shallow, near-shore environments. Highest variability occurs near lake inflows, in shallow water settings, and at sites disturbed by land use activities. There is an overall non-linear decrease in sedimentation rates with increasing distance from the lake inflows; however, this pattern is disrupted in deep water sites of intervening lake sub-basins where locally higher accumulation rates are recorded. This trend of increased sedimentation with water depth is most pronounced in the proximal basin and becomes less significant in more distal sub-basin settings. These relations are quantitatively described by an empirically derived sedimentation model. Discernible patterns of spatial variability exceed resolved temporal variability by an order of magnitude. Major sediment delivery events of the last 70 years, discriminated at intra-annual to annual scales, include rapid glacial recession of the early 20lh century, extreme late-summer and autumn rainstorm floods, and unusual snowmelt conditions. Some years of anomalous sedimentation can be related to the occurrence of multiple sediment delivery events and other associated geomorphic processes, including Quaternary valley fill landslides and major channel destabilization effects. Stratigraphic characteristics and spatial sedimentation patterns vary between different types of moderate and extreme sediment delivery events in relation to the defined average-regime deposition model. Total sediment yield is calculated to average 205 Mg/km²/yr, with suspended load, bedload, and dissolved load components accounting for similar proportions of the total yield when integrated over the contemporary period. At inter-annual time scales, temporal variability primarily reflects sediment delivery processes associated with rapid glacial recession observed during the 1930's and early 1940's and extreme autumn rainstorm effects occurring in the early 1990's. Sediment yield responses between events and transfer components differ considerably with respect to magnitude, lag time, and duration.Arts, Faculty of
Geography, Department of
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Larocque, Sonya J. "Glacial and climatic fluctuations during the Little Ice Age, Mt. Waddington area, southern coast mountains of British Columbia, Canada." 2003. http://hdl.handle.net/1828/389.
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Charbonneau, Ansley Adeline. "Rock glacier activity and distribution in the southeastern British Columbia Coast Mountains." Thesis, 2015. http://hdl.handle.net/1828/6040.
Full textAbstract:
Rock glaciers are common features in high alpine settings of the southeastern British Columbia Coast Mountains. The spatial distribution and characteristics of these periglacial features have not previously been documented. The goal of this research was to determine the distribution and activity of these rock glaciers in order to characterize their periglacial response to climatic variability.
A high-resolution aerial inventory documented the presence of 187 rock glaciers between Lat. 50° 10’ - 52° 08’ N. These rock glaciers occur at sites located between 1900 m and 2400 m above sea level, where rain shadow effects and continental air masses result in persistent dry cold conditions. Intact rock glaciers were the most prevalent form and accounted for almost 90% of the rock glaciers included in the inventory. Glacier-derived features outnumbered talus-derived features by a ratio of 4:1 and only 22 relict rock glaciers were identified. Rock glaciers in this region occupy predominately northwest- to northeast-facing slopes, with talus-derived rock glaciers largely restricted to north-facing slopes. All rock glaciers were found at locations above presumed Younger Dryas terminal moraines, suggesting that they began to form after 9390 BP.
Rock glacier activity during the Late Holocene was characterized using lichenometric methods to establish the relative surface age of three talus-derived features at Perkins Peak. Sustained periods of cool-wet climates activated pulses of rock glacier surface instability and movement, while a shift to warmer, drier conditions resulted in the loss of internal ice and increased surface stability. Varying degrees of present-day activity highlight a local topoclimatic control on talus-derived rock glacier behaviour. A dendrogeomorphological investigation at nearby Hellraving rock glacier indicated that it has been steadily advancing into surrounding forest since the beginning of the late Little Ice Age. Its continued advance in the face of warming temperatures suggests the internal thermodynamics of this rock glacier may be out of equilibrium with the contemporary climate. This research is the first to document and characterize rock glaciers in the Coast Mountains and challenges previous understandings of permafrost distribution in the southwestern Canadian Cordillera.Graduate
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St-Hilaire, Vikki Maria. "Holocene glacial history of the Bowser River Watershed, Northern Coast Mountains, British Columbia." Thesis, 2014. http://hdl.handle.net/1828/5817.
Full textAbstract:
Accelerated glacial recession and downwasting of glaciers in the Bowser River Watershed of the northern British Columbia Coast Mountains have exposed subfossil wood remains and laterally contiguous wood mat layers. To develop an understanding of Holocene glacial fluctuations in this region, field investigations were conducted in 2005, 2006 and 2013 at Frank Mackie, Charlie, Salmon and Canoe glaciers. These wood remains represent periods of Holocene glacier advance, when glaciers expanded and overwhelmed downvalley forests.
Dendroglaciology and radiocarbon analyses revealed five intervals of glacial expansion: (1) a mid-Holocene advance at 5.7-5.1 ka cal. yr BP; (2) an early Tiedemann advance at 3.6-3.4 ka cal. yr BP; (3) a late Tiedemann advance at 2.7-2.4 ka cal. yr BP; (4) a First Millennium AD Advance at 1.8-1.6 ka cal. yr BP; and, (5) three advances during the Little Ice Age at 0.9-0.7, 0.5 and 0.2-0.1 ka cal. yr BP. These results provide new evidence for mid-Holocene glacier activity in northern British Columbia, as well as supporting previous research that Holocene glacier advances were episodic and regionally synchronous.Graduate
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Vanags, Anthony. "An archaeological perspective on alpine/sub-alpine land use in the Clear Range and Pavilion Mountains, south-central British Columbia." Thesis, 2001. http://hdl.handle.net/2429/11489.
Full textAbstract:
This study uses two independent surveys of the Alpine/Sub-alpine environmental zones of the
Clear Range and Pavilion Mountain to explore the nature of the archaeological record in the higher
elevations of the Southern Interior Plateau of British Columbia. The archaeological site information is
derived from the original site records as well as a lithic analysis of associated assemblages. The
archaeological material is examined in relation to ethnographic subsistence and settlement patterns,
archaeological pattering in Upland Valleys (Upper Hat Creek Valley), and to other investigated
Alpine/Sub-alpine areas such as the Cornwall Hills and Potato Mountain. Neither the Ethnographic nor
Upland Valley Models provided a perfect fit for the archaeological information, but these two models did
provide the foundation upon which the archaeological site classes could be derived. The results were clear
in that the Alpine/Sub-alpine zones were an important part of the seasonal round for both hunting and plant
food gathering/processing activities and were not just an extension of the Upland Valley zones. The
diagnostic artifacts recovered from the Clear Range and Pavilion Mountain suggest that this area, and more
specifically the Alpine/Sub-alpine environmental zones, have been used for hunting purposes for
approximately 7000 years, though most of the dates are concentrated between 3500 and 200 BP. There are
fewer dates for plant gathering and processing activities, but the radiocarbon dates suggest that plant
processing started approximately 2000 BP. The majority of the archaeological sites for both the Clear
Range and Pavilion Mountain are situated within the Montane Parkland environmental zone. Even so, the
Alpine/Sub-alpine zones in the Clear Range and Pavilion Mountain were used differently. The Clear Range
was used for both hunting and plant gathering/processing activities, while Pavilion Mountain and the
Cornwall Hills were used primarily for hunting activities. Only on Potato Mountain were the majority of
sites related to plant gathering/processing activities.
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Jordan, Robert Peter. "Debris flows in the southern Coast Mountains, British Columbia : dynamic behaviour and physical properties." Thesis, 1995. http://hdl.handle.net/2429/8796.
Full textAbstract:
Debris flows in the southern Coast Mountains exhibit different dynamic and
sedimentologic characteristics, depending on the lithology of their source areas. Fine-textured
debris flows originating in the Quaternary volcanic complexes are much more mobile than those
originating in the coarse-textured plutonic rocks which form most of this mountain range.
Mobility can be described as the velocity of flow, the distance of travel of debris flows, and the
slope required to sustain flow. The objectives of this study are to examine the effect of different
sediment composition on the mobility of debris flows, and to determine which rheologic models
are most applicable for modeling debris flows in these geologic environments.
About 25 debris flow events in or adjacent to the southern Coast Mountains were
examined, ranging in volume from 10² m³ to over 10⁷ m³. Field methods included sampling of
grain-size distribution, measurement of the deposit and channel dimensions, and observation of
the stratigraphy of debris flow fans. Shear strength, permeability, and consolidation tests were
performed on samples of reconstituted debris, representative of typical fine-textured and coarsetextured
debris flows. These samples were also used to model debris flows in a flume.
The coarse-textured, plutonic-source, debris flows typically had a distinct, inverselygraded,
clast-supported, surface layer of cobbles and boulders. Their deposits tended to be
irregular in thickness, with lobes and levees of coarse material. The fine-textured, volcanicsource,
debris flows had no such surface layer, and their deposits were generally uniform in
thickness and surface morphology. These observations, and corroborating evidence from the
flume results, suggest that fine-textured debris flows behave according to the Bingham flow
model, while coarse-textured debris flows can be better described by a granular, or dilatant, flow
model. A clay content of about 4% in the matrix (sub-4 mm material) is a useful measure to
distinguish the two populations. Several debris flow events of intermediate behaviour and
sediment composition were also examined. The permeability of the debris, and hence its rate of
consolidation, is an important factor controlling mobility. The volume of debris flow events was
found to be the most significant factor controlling runout distance.
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Pitman, Kara Jane. "Extending the duration and dendroclimatic potential of mountain hemlock (Tsuga mertensiana) tree-ring chronologies in the southern British Columbia Coast Mountains." Thesis, 2011. http://hdl.handle.net/1828/3772.
Full textAbstract:
Tree-ring records collected from living mountain hemlock trees in the southern British Columbia Coast Mountains have been used to provide insights into the character of historical climatic fluctuations and the behaviour of individual climate forcing mechanisms. The relatively short-duration of these records limits, however, their ability to describe climate variability and atmospheric processes that change gradually or undergo long-term regime shifts. The objectives of this research were to extend the duration and quality of proxy climate information extracted from mountain hemlock tree-ring chronologies.
In coastal British Columbia most existing mountain hemlock tree-ring chronologies extend from ca. AD 1600 to present. To extend the duration of these chronologies, coarse woody debris recovered from the bottom of M Gurr Lake, a high-elevation lake in the vicinity of Bella Coola, British Columbia, was cross-dated to nearby living chronologies surrounding M Gurr lake and increment core samples of ancient trees at Mt Cain on northern Vancouver Island. From this, a regional continuous 917-year long record of radial growth was constructed. The resulting regional chronology was used to construct a 785 year-long proxy record of gridded air temperature anomalies displaying periods of cooler and warmer than average regional air temperatures that contained century-long low frequency trends. Cross-dating and tree morphological evidence of snow avalanche activity displayed within living trees surrounding the lake, and within the coarse woody debris, revealed that low-magnitude avalanches occurred in the winter months of AD 1713-1714, 1764-1765, 1792-1793, 1914-1915, 1925-1926, and 1940-1941. High magnitude avalanche events occurred in the winter months of AD 1502-1502 and 1868-1869.
A second objective of the thesis was to investigate the radial growth response of mountain hemlock trees to subseasonal climate variables using standardized ring-width and densitometric analyses. Mountain hemlock chronologies from M Gurr Lake, Cyprus Provincial Park, and Mount Arrowsmith were used to describe the inherent climate-growth trends. Maximum annual tree-ring density values provided a robust data series for constructing site-specific proxy records of late-summer temperature. Annual tree-ring width measurements provided independent proxies of spring snowpack trends. Regionally-derived proxy models indicated that intervals of cooler-than-average and higher-than-average air temperatures correspond to years of higher-than-average average and cooler-than-average snowpacks, respectively. Of note were the significant decreases in air temperature and increases in snowpack depths during the early-1700s and early-1800s coinciding with documented glacier advances in the Coast Mountains. Identification of these subseasonal climate signals within the tree-rings of mountain hemlock trees demonstrates the value of incorporating investigations of multiple tree-ring parameters.Graduate
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Johnson, Kate. "Late Holocene climate and glacier fluctuations in the Cambria Icefield area, British Columbia Coast Mountains." Thesis, 2010. http://hdl.handle.net/1828/3345.
Full textAbstract:
In the British Columbia Coast Mountains most dendroclimatological and dendroglaciological studies have focused on developing insights from tree‐ring sites located in the southern and central regions. By contrast relatively few studies have been conducted in the northwestern Coast Mountains, where exploratory studies reveal that significant climate‐radial growth relationships exist. The purpose of this study was to develop a proxy record of climate change from tree rings and to reconstruct the late Holocene glacial history of two outlet glaciers spilling eastward from th
e Cambria Icefield. Dendroclimate investigations were conducted using mountain hemlock (Tsuga mertensiana) trees growing on three high‐elevation montane slopes. The three stands located along a 35 km transect cross date to form a master chronology for the region spanning 409 years (1596 to 2007 A.D.). Correlation analyses show that the radial growth of the regional tree‐ring chronology corresponds to variations in the mean June‐July‐August (JJA) air temperature. The relationship between the two variables was used to reconstruct mean JJA air temperature from 1680 to 2007 A.D.). The reconstruction illustrates warm and cool intervals that are synchronous
ito those derived from other paleoenvironmental research in this region. The proxy record also highlights annual to inter‐decadal climate variability likely resulting from atmospheric‐ocean circulation patterns described by the El Niño‐Southern Oscillat
ion and the Pacific Decadal Oscillation. The late Holocene behaviour of White and South Flat glaciers was investigated using radiocarbon dating techniques, dendrochronological cross‐dating techniques and geomorphological analysis of sedimentary units within the White and South Flat glacier forefields. Evidence for a First Millennial Advance (FMA) cumulating around 650 A.D. and early Little Ice Age (LIA) advances at 1200 and 1400 A.D. were documented. These advances are contemporaneous with the late Holocene activity of glaciers throughout the region, suggesting coherent broad‐scale climate forcing mechanisms have influence glacial mass balance regimes over at least the last two millennia. The dendroclimatological and dendroglaciological findings of the study provide the first annually‐resolved climate record for the region and help to enhance our understanding of late‐Holocene glacier behaviour in the Cambria Icefield Area. The thesis documents the complex interactions between climate and the radial growth of mountain hemlock trees in the Pacific Northwest, and describes the role that long‐term climate variability played in glacier dynamics during the FMA and LIA.Graduate
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Coulthard, Bethany L. "Dendroclimatological and dendroglaciological investigations at Confederation and Franklin glaciers, central Coast Mountains, British Columbia, Canada." Thesis, 2009. http://hdl.handle.net/1828/3101.
Full textAbstract:
It has become increasingly clear that climate fluctuations during the Holocene
interval were unusually frequent and rapid, and that our current understanding of the
temporal and spatial distribution of these oscillations is incomplete. Little
paleoenvironmental research has been undertaken on the windward side of the central Coast Mountains of British Columbia, Canada. Very high annual orographic precipitation totals, moderate annual temperatures regulated by the Pacific Ocean, and extreme topographic features result in a complex suite of microclimate conditions in this largely unstudied area.
Dendroclimatological investigations conducted on a steep south-facing slope near
Confederation and Franklin glaciers suggest that both mountain hemlock (Tsuga
mertensiana) and subalpine fir (Abies lasiocarpa) trees at the site are limited by previous year mean and maximum summer temperatures. A regional subalpine fir chronology for the central and southern Coast Mountains indicates that subalpine fir trees at the study site experience physiological stress with warm summer temperatures, despite the high
annual precipitation totals experienced there. This response is likely a result of the extreme gradient and the aspect of the slope at the sampling location, underscoring the importance of site characteristics on annual radial tree growth. Local (AD 1820-2008) and regional (AD 1700-2008) tree ring width chronologies were used to reconstruct
previous July mean and maximum temperatures, explaining between 13% and 36% of the
variance in climate. The proxy record features cool intervals that are comparable to other paleoenvironmental research from the region, and cyclical oscillations in temperature commonly associated with the El Niño Southern Oscillation and Pacific Decadal
Oscillation. Century-scale fluctuations may be connected to changes in solar irradiance.
Dendroglaciological investigations were undertaken at the confluence of the
Confederation and Franklin glaciers with the intention of exploring the Holocene
behaviour of low-elevation maritime glaciers in this region. These glaciers are suspected
to be sensitive to variations in the mean position of winter freezing level heights and
warm winter temperatures, and may respond differently to changes in climate than more
continental glaciers. Buried wood samples were radiocarbon-dated and cross-dated to
construct three floating chronologies. Float A (r = 0.467) suggests an early Little Ice Age advance of the two glaciers, and Float B (r = 0.466) suggests an early Tiedemann
advance of Confederation Glacier. Float C (r = 0.519) is dated to the Garibaldi Phase of
glacier expansion, but may not have been killed by glacial activity. The temporal
synchronicity of these findings with glacial events documented throughout the region
suggests a spatially coherent response of maritime and continental glaciers to the
dominant climate–forcing mechanisms operating in Pacific North America throughout
the late Holocene.
The dendroclimatological and dendroglaciological findings of this study help to fill a spatial research gap in the current understanding of Holocene climate variations in British Columbia. Because of the complex and at times topographically-controlled response of conifers to climate in the study area, this region may provide a particular challenge in terms of reconstructing Holocene climate variability.
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Craig, Jessica Aileen. "Late Holocene glacial history of Scimitar Glacier, Mt. Waddington area, British Columbia Coast Mountains, Canada." Thesis, 2012. http://hdl.handle.net/1828/4394.
Full textAbstract:
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.Graduate
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Burnim, Joshua W. "Sawtooths to Selkirks : connecting the wild in Idaho, Montana, and British Columbia /." 2004.
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Mood, Bryan Joel. "Latest Pleistocene and Holocene behaviour of Franklin Glacier, Mt. Waddington Area, British Columbia Coast Mountains, Canada." Thesis, 2015. http://hdl.handle.net/1828/6111.
Full textAbstract:
Holocene climate variability in the British Columbia Coast Mountains has resulted in repeated intervals of glacier expansion and retreat. Since reaching their late Holocene maximum positions in the late 20th century, glaciers in the region have experienced significant volumetric loss. The subsequent downwasting and frontal retreat has revealed forests buried by glacier advances throughout the Holocene, enabling description of significant intervals of ice expansion using dendroglaciology. This thesis characterizes dendroglaciological evidence as it relates to climate at two scales: (1) at Franklin Glacier in the Mt. Waddington area, and; (2) throughout the Coast Mountains.
Dendroglaciological evidence from glacier forefields and lateral moraines in the Coast Mountains provides evidence for at least 11 intervals of glacier activity during the Holocene. The earliest record glacier activity is documented in the Pacific Ranges from 8.5 to 7.8 ka, after which glaciers in this region retreated during the early Holocene warm and dry interval. Following this a glacial advance from 6.7 to 5.6 ka was followed by a subsequent expansion episode from 5.1 to 4.6 ka in response to attendant cool and moist conditions in the Pacific Ranges. After 4.6 ka, glaciers in the Pacific and Boundary ranges advanced at 4.4 to 4.0 and 3.8 to 3.4 ka during intervals characterized wet conditions resulting from an intense, eastwardly positioned Aleutian Low pressure centre. Following 3.4 ka most glaciers retreated before expanded between 3.2 and 2.8 ka, retreated, and then advanced from 2.6 to 2.4 ka. Glacier advances from 1.8 to 1.1 ka occurred in response to a regional cooling event, and proceeded Little Ice Age advances from 0.6 to 0.4 ka.
Franklin Glacier is an 18-km long valley glacier that originates below the west face of Mt. Waddington. Radiocarbon-dated wood samples from the proximal faces of lateral moraines flanking the glacier show that it expanded at least nine times since 13 ka. A probable Younger Dryas advance of Franklin Glacier at 12.8 ka followed the late glacial retreat and downwasting of the Cordilleran Ice Sheet from ca. 16.0 to 12.9 ka. During the succeeding early Holocene warm period, Franklin Glacier appears to have retreated significantly, leaving no record of glacial expansion until the mid-Holocene when it repeatedly advanced at 6.3, 5.4, and 4.6 ka in response to cool summer temperatures and generally moist conditions. Downwasting of the glacier surface after 4.6 ka was followed by intervals of expansion at 4.1, 3.1, and 2.4 ka contemporaneous with a period of increased precipitation. Following ice expansion at 2.4 ka into trees over 224 years in age, there is no record of the glacier activity until 1.5 ka when Franklin Glacier thickened and advanced into young subalpine fir trees, reflecting attendant cool and wet environmental conditions. During the Little Ice Age, advances at 0.8 and 0.6 ka preceded a mid-19th to early-20th century advance that saw Franklin Glacier attain its maximum Holocene extent in response to an extended interval of cold temperatures.
The dendroglaciological record at Franklin Glacier is among the most comprehensive recovered from the British Columbia Coast Mountains and showcases the complexity of latest Pleistocene and Holocene glacier behaviour in the region.Graduate
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bjmood@uvic.ca
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Knapp, Caroline J. "Late Ordovician solitary rugose corals of the Beaverfoot Formation, southern Rocky Mountains, British Columbia and Alberta." 1985. http://hdl.handle.net/1993/28851.
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Koehler, Lindsey. "Late Holocene glacial history of Manatee Valley, Upper Lillooet Provincial Park, southern Coast Mountains, British Columbia." Thesis, 2009. http://hdl.handle.net/1828/2821.
Full textAbstract:
This investigation uses dendrochronologic and radiometric techniques to infer the
timing of glacier advance for four ice lobes that are drained by Manatee Creek in a
remote valley located in the southern Coast Mountains, British Columbia.
Dendroglaciologic evidence exposed by retreating glaciers provides evidence for
increasing complexity in the Holocene glacial record, particularly for mid-late Holocene events. Since Holocene ice fronts periodically extended below treeline in the region, previous glacier advances overrode and buried forests beneath till deposits. The
dendroglaciologic evidence presented here corroborates the record of glacier advances
described for other southern British Columbia Coast Mountain glaciers and details ice front position at ca. 4270 14C yr BP, 3430 14C BP and 2350 14C yr BP. Well-preserved sequences of lateral, nested moraines were mapped and profiled to delineate the boundaries of Manatee and Oluk glaciers. Relative dates provided by lichenometry and dendrochronology were used as limiting dates for the deposition of 5-6 moraines during the late 14th, early 16th, early 18th, 19th, and early-20th Century. Reconstructions of Holocene glacial history offer insight into the regional, climatic regime and add to the discussion about pervasive, millennial-scale cycles.