Talus slopes were investigated in a process-material-response framework. The work was concerned with clarifying concepts and terminology concerning slopes of granular materials and interpreting talus slope angles in the light of this clarification; verifying this interpretation in a field investigation; and seeking statistical relationships between talus slope angle and material properties. Field investigations were carried out in South West British Columbia. Slopes were investigated in the southern Coast Mountains and. in the Similkameen Valley. Theoretical concepts relating to slopes in granular material were discussed. Two angles of repose were distinguished; a peak angle of accumulation (α[sub c]) defined as the steepest angle attainable by a mass of granular material, and a lower angle, the angle of repose (α[sub r]) to which the material slides after failure. α[sub c] and α[sub r] were related to concepts of shear resistance and the angle of internal friction (0); α[sub c] was linked to 0 and α[sub r] was thought to correspond to the residual angle of internal friction for a given material. α[sub c] and α[sub r] were related through a regression equation of the form; α[sub c] = -3.29 + 1.273 (α[sub r]) These concepts were examined with reference to talus slope form and some of the contradictions in the literature were presented. The characteristic and limiting slope angles noted in review were found to correspond to α[sub r] and α[sub c] respectively for talus material. This correspondence gave rise to the supply induced transformation hypothesis which appeared to provide a suitable transformation model for rock-fall talus. The relationship between material properties and slope angle was examined using parametric multivariate statistics. Significant correlations, at the 99% level, were obtained between segment angle and size (inverse) and segment angle and sorting (direct). At the 95% level significant correlations were found between segment angle and sphericity (inverse) and Zingg's Flatness Ratio (direct). In multiple regression analysis only 37.11% of the variation in slope angle was accounted for by material properties (sorting and the variance in Zingg's Elongation Ratio) at the 95% level of significance. Shape factors contribute very little to the explained variance whilst fabric related variables contribute nothing. Implications of these results for talus slope development were discussed. Rockfall talus slopes subject to supply-induced transformation processes are thought to have a distinctive morphology which may be an explanation for the typical profile concavity noted on such slopes. Determinants on the frequency of talus slides were examined. The problem of the basal layer cannot be ignored in a consideration of talus slope development models. / Arts, Faculty of / Geography, Department of / Graduate

No description available.

No description available.

The Albian Lower Skeena Group in the Telkwa coalfield comprises more than 500 metres of conglomerate, sandstone, siltstone, mudstone and coal deposited during two regressive/transgressive cycles. The stratigraphic sequence is divisible into four lithostratigraphic units. The basal unit, Unit I, may be more than 100 metres thick and comprises conglomerate, sandstone, mudstone, coal, and seat earth. Conglomerate and sandstone are composed dominantly of chert and volcanic rock fragments, and mudstones are kaolinitic. Unit I was deposited in a fluvial environment on an eroded volcanic basement. Gravel and sand were deposited in braided channels and bars, and mudstone accumulated in floodplains. Coal formed in poorly drained, peat-forming backswamps. In the northern part of the study area, coal seams thin and split, a result of periodic flooding of peat swamps with sediment-laden water from nearby streams. Deposition of Unit I ended with a marine transgression and deposition of Unit II. Unit II consists of up to 140 metres of silty mudstone, bioturbated or cross-bedded, chert and muscovite-rich sandstone, and rare thin coaly mudstones deposited in a deltaic/shallow marine environment. Sand was deposited in distributary channels and mouth-bars, mud accumulated in bays, and thin discontinuous peat beds accumulated in local salt marshes. There is structural evidence for the presence of an unconformity within Unit II, but palynological and paleontological data suggest that the strata are all similarly aged. Unit III averages 90 metres thick, and comprises bioturbated or rippled, chert and muscovite-rich sandstone, siltstone, carbonaceous mudstone and thick, laterally extensive coal seams deposited in a variety of low-energy, paralic environments. Sand and mud were deposited and biogenically reworked in tidal flats, and siltstone accumulated in a restricted, nearshore marine environment in the eastern edge of the study area. Peat accumulated in freshwater coastal marshes which periodically prograded over tidal flats. All but the lowermost coal seams pinch out eastward into restricted, nearshore marine sediments, and the ash content of the coal increases toward the margin of the seam. Locally, the sulphur content of the coal is high, reflecting occasional inundation of the fresh-water swamps by brackish water. High sulphur coal contains relatively more pyritic sulphur and less organic sulphur, compared to low-sulphur coal. Unit IV is at least 150 metres thick and is composed of chloritic, green sandstone overlain by silty mudstone, deposited in a marine environment. The basal sandstone is a transgressive lag deposit, and silty mudstone, the predominant lithofacies, was deposited in a nearshore, shallow marine environment. The provenance of the sediments in the Telkwa coalfield changes from the base to the top of the stratigraphic section. Conglomerate and sandstone of Unit I contain an abundance of volcanic clasts and grains, locally derived from underlying and surrounding volcanic rocks of the Jurassic Hazelton Group, which were uplifted as part of the Skeena Arch and subsequently eroded and reworked. Sandstones of Units II, III and IV, which contain much less volcanic-derived material and an abundance of mica flakes, were derived from high-grade metamorphic rocks in the Omineca Belt. Chert grains are abundant throughout, reflecting continued clastic influx from the Pinchi Belt-Columbian Orogen. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Grand Forks-Eholt map area is underlain predominantly by a sequence of moderately deformed and slightly metamorphosed sedimentary and volcanic rocks, previously termed the "Anarchist Group" and ranging in age from Permian/or Earlier to Middle Jurassic. These rocks are divisible into two distinct sequences: (a) cherts (Knob Hill), quartzites, phyllites, and greenstones of Permian/or Earlier age. The term Anarchist Group is now restricted to this lower sequence which resembles the Cache Creek Assemblage (Penn.-Lower Triassic) widespread throughout southcentral B.C.; (b) Sharp-stone Conglomerate/Brooklyn Limestone sequence (Middle-Upper Triassic), and overlying Fragmental Andesites (Middle Jurassic) which correlates with the Takla-Hazelton Assemblage (Middle Triassic - Middle Jurassic) in north central B.C. This upper sequence rests unconformably on the lower and the Sharpstone Conglomerate forms the basal conglomerate separating the two sequences. The Grand Forks Group (pre-Cambrian/or Early Paleozoic), consisting of paragneisses, minor marble and amphibolites crops out east of the Granby River Fault. The fault forms approximately the eastern boundary of the map area. Latest Jurassic Nelson granodiorites; Latest Cretaceous quartz-diorite, quartz-monzonite porphyries, leuco-gabbros and diorites; and Eocene Coryell syenites and related alkalic rocks intrude the sediments and volcanics predominantly in the northern part of the map area. The Nelson granodiorites occur as large batholith-like masses and the younger intrusions form small irregular plugs, dykes and sills. A NNE to N trending nearly recumbent synclinal structure is outlined within the Sharpstone Conglomerate/Brooklyn Limestone/Fragmental Andesite sequence. It is transected by prominent NW trending shear/fault zones and has been broken by these into blocks that are downdropped and shifted to the southwest from north to south in the map area. The eastern part of the map area is transected by the NNE trending Granby River Fault which forms the northern projection of the Eastern Boundary Fault of the Republic Graben - a major structural element to the south in Washington State. Prominent NW and NE Late Cretaceous to Tertiary fractures are ubiquitous and often filled by sheared serpentinites and Tertiary pulaskite and diorite dykes. The Middle Jurassic and older sediments and volcanics have been regionally metamorphosed to the Greenschist Facies. The Grand Forks Group to the east has undergone metamorphism to the Almandine-Amphibolite Facies. Large hornfelsed metasedimentary aureoles surround the larger Nelson granodiorite masses. The Brooklyn Limestone has been thermally altered to marble and locally to chalcopyrite-magnetite bearing calc-silicate skarns, which are often of economic value. Thin contact thermal aureoles surround the Latest Cretaceous quartz-diorite and quartz-monzonite porphyry plugs and dykes, indicating high level intrusion. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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

No description available.

No description available.

No description available.

Fossil plant remains from the "upper sedimentary-unit" of the Hazelton Group were investigated in order to attempt the assignment of a precise age to the strata. Collections of leaves and specimens for plant microfossil analysis were collected in the Hazelton area, and were supplemented by leaf collections loaned by the Geological Survey of Canada. Intensive maceration of rock specimens failed to yield sufficient microfossils for dating or correlation, and subsequent work was limited to the analysis of megafossils. Identification of leaves and other remains resulted in the discovery of one new species and the recognition of 7 species previously unreported in the Hazelton flora. Statistical analyses and correlations with other floras have led to the conclusion that, the flora from the "upper sedimentary unit" of the Hazelton Group is late Jurassic to early Cretaceous in age, encompassing the stages Portlandian to Neocomian inclusive. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate