The majority of the Middle Cambrian Wheeler Formation in the Drum Mountains was deposited during a single 3rd order sequence. Superimposed onto this sequence are three indistinct 4th order cycles and twenty distinct 5th order cycles. These higher other cycles were likely deposited within short intervals of geologic time (204 to 405 ky). The lower sequence boundary zone occurs within the Swasey Formation. The Transgressive Surface is the contact between the Swaset and Wheeler Formations. The Maximum Flooding Surface is located near the top of the lower Wheeler Formation, which also approximates the base of the Ptychagnostus atavus range zone. The upper sequence boundary is marked by stromatolites, which occur near the top of the upper member of the Wheeler Formation in the Drum Mountains. Deposition of the Wheeler Formation in the Drum Mountains was controlled by eustacy and tectonics. Local normal faulting associated with Middle Cambrian postrifting thermal subsidence may have caused some of the 5th order cycles. The cycles and surfaces defined in this stratigraphic analysis, and the base of the Ptychagnostus atavus and P. gibbus range-zones, can be used to correlate strata occurring in other localities in the eastern Great Basin. In addition, this study enables the evaluation of the effect of tectonics (faulting) versus global eustacy on the sedimentary regime occurring within the Middle Cambrian House Range Embayment. (95 pages)

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The study investigates the habitat preferences and ecological adaptations of the klipspringer in the Namaqualand and the southern Cape mountains. Klipspringer social organisation was found· to consist of a monogamously mated pair defending a territory which varies in size according to rainfall. The pair bond is very strong and role differentiation occurs, with the male spending more time than the female in anti-predator vigilance. Anatomical and physiological adaptations include a modified digit structure, kidneys with a high concentrating ability, and a unique pelage for insulation. Seasonal variations in activity patterns and feeding preferences are discussed in relation to weather conditions, metabolic requirements and possible plant defensive mechanisms. Klipspringers avoid competition with other small antelope by preferring more rocky terrain, and possible methods of food separation from dassies are suggested. The significance of all these factors in relation to the conservation and management of klipspringer populations is examined. / Dissertation (MSc)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted

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. / Arts, Faculty of / Geography, Department of / Graduate

Retrogressive thaw slumps are one of the most dramatic thermokarst landforms in periglacial regions. This thesis investigates the impacts of two of the largest hillslope thaw slumps on the geochemistry of periglacial streams on the Peel Plateau, Northwest Territories. It aims to describe the inorganic geochemistry of runoff across active mega-slumps, impacted and pristine tundra streams, as well as that of the ice-rich permafrost exposed in the slump headwalls. Slump runoff is characterized by elevated suspended sediments (911 g/L), high conductivity (2700 µS/cm), and high SO42- ( up to 2078 ppm). The runoff originates as a solute-rich meltwater near the slump headwall, and leaches and re-dissolves soluble salts (e.g., gypsum) as it flows along the mudflow. Conductivity increases until the runoff mixes with pristine tundra streams, diluting the slump runoff signal. SO42-/Cl- is used as a tracer to isolate the slump runoff signal in impacted waters, and suggests that the contribution of slump runoff to the Peel River has been increasing since the 1960s.

Ogilvie Mountains breccia (OMB) is in Early (?) to Late Proterozoic rocks of the Coal Creek Inlier, southern Ogilvie Mountains, Yukon Territory. Host rocks are the Wernecke Supergroup (Fairchild Lake, Quartet and Gillespie Lake groups) and lower Fifteenmile group. Distribution and cross-cutting relationships of the breccia were delineated by regional mapping. OMB was classified by clast type and matrix composition. Ogilvie Mountains breccia crops out discontinuously along two east-trending belts called the Northern Breccia Belt (NBB) and the Southern Breccia Belt (SBB). The NBB extends across approximately 40 km of the map area, and the SBB is about 15 km long. Individual bodies of OMB vary from dyke- and sill-like to pod-like. The breccia belts each coincide with a regional structure. The NBB coincides with a north side down reverse fault—an inferred ruptured anticline—called the Monster fault. The SBB coincides with a north side down fault called the Fifteenmile fault. These faults, at least in part, guided ascending breccia. The age of OMB is constrained by field relationships and galena lead isotope data. It is younger than the Gillespie Lake Group, and is at least as old as the lower Fifteenmile group because it intrudes both of these units. A galena lead isotope model age for the Hart River stratiform massive sulphide deposit that is in Gillespie Lake Group rocks is 1.45 Ga. Galena from veinlets cutting a dyke that cuts OMB in lower Fifteenmile group rocks is 0.90 Ga in age. Therefore the age of OMB formation is between 1.45 and 0.90 Ga. Ogilvie Mountains breccia (OMB) has been classified into monolithic (oligomictic) and heterolithic (polymictic) lithologies. These have been further divided by major matrix components—end members are carbonate-rich, hematite-rich and chlorite-rich. Monolithic breccias with carbonate matrices dominate the NBB. Heterolithic breccias are abundant locally in the NBB, but are prevalent in the SBB. Fragments were derived mainly from the Wernecke Supergroup. In the SBB fragments from the lower Fifteenmile group are present. Uncommon mafic igneous fragments were from local dykes. OMB are generally fragment dominated. Recognized fragments are up to several 10s of metres across and grade into matrix sized grains. Hydrothermal alteration has locally overprinted OMB and introduced silica, hematite and sulphide minerals. This mineralization has received limited attention from the mineral exploration industry. Rare earth element chemistry reflects a lack of mantle or deep-seated igneous process in the formation of OMB. However, this may be only an apparent lack because flooding by a large volume of sedimentary material could obscure a REE pattern indicative of another source. The genesis of OMB is significantly similar to modern mud diapirs. It is proposed that OMB originated from pressurized, underconsolidated fine grained limey sediments (Fairchild Lake Group). These were trapped below and loaded by turbidites (Quartet Group) and younger units. Tectonics and the initiation of major faults apparently triggered movement of the pressurized fluid-rich medium. The resulting bodies of breccia are sill-like and diapir-like sedimentary intrusions. Fluid-rich phases may have caused hydrofracturing (brittle failure) of the surrounding rocks (especially in the hanging wall). Breccia intrusion would have increased the width of the passage way while encorporating more fragments. Iron- and oxygen-rich hydrothermal fluids apparently were associated with the diapirism. Presumably these fluids are responsible for the high contents of hematite and iron carbonate in fragments, and especially, in the matrix of the breccias. Exhalation of these fluids may have formed the sedimentary iron formations that are spatially associated with the breccias. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

In March of 1987, the Geologic Survey of Canada conducted a major seismic refraction experiment in the Mackenzie Delta-Southern Beaufort Sea-Northern Yukon area. This study involves the analysis of a portion of the resulting data set. A 2D velocity profile through the Richardson Mountains of the northern Yukon has been constructed using raytracing to model the travel-times and amplitudes. The line is approximately 320 km long, running from a shotpointon the Eagle Plains in the south to one 50 km offshore in Mackenzie Bay to the north, with an average receiver spacing of 3.5 km. An additional shotpoint is located at Shingle Point, on the shore of Mackenzie Bay. A series of four sedimentary basins separated by major structural highs produces a complex basement structure. Two distinct upper crustal layers were modelled, a 5.95 km/s layer overlying a 6.3 km/s layer, as well as a lower crustal layer with a velocity of 7.25 km/s. Crustal velocity gradients are low (≤ 0.005 s⁻¹). The 6.3 km/s layer pinches out beneath the Beaufort-Mackenzie Basin in the north, accompanied by a thinning of the lower crust from a thickness of 20 km in the south to less than 10 km beneath MB. This results in the crust as a whole thinning from a thickness of 50 km under the Richardson Mountains to only 40 km under the Beaufort-Mackenzie Basin. The velocity of the upper mantle is 7.95 km/s. The modelling of shear wave arrivals indicate Poisson's ratios of 0.23 ±0.02 in the upper crust and 0.25 + 0.02 in the lower crust. / 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

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