4 resultados para Near earth objects

em Brock University, Canada


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Cross sections of excavation required to make a ditch on the earth side of the railroad near Port Dalhousie. This is a 12 page booklet of hand- drawn charts and diagrams which is slightly stained. Text is not affected, Mar. 1860.

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The quartzite microfabric found in the Lorrain Formation was studied across the La Cloche syncline, along a regional north-south transect along highway 6, near Whitefish Falls, Ontario. The complete stratigraphic sequence across the syncline is preserved, and is present on each fold limb. The lithostratigraphic units with the smallest grains size and lowest mica content are located close to the core of the fold, while coarser grained mica and feldspar rich units are situated at the northern and southern most extent of the transect. Deformation mechanisms vary with lithology and with position across the fold. Pressure solution appears to be the dominant deformation mechanism in the feldspathic, micaceous and ferruginous units. In the finer grained, mica poor white medium grained and cherty sandstone units, grain boundary migration (GBM) characteristics show dominance over those of pressure solution and show high amounts of fracturing which cut migrated boundaries and therefore post date GBM. All samples across the fold display a preferred orientation of quartz c-axes. The senses of asymmetry of fabrics are found to be similar across the syncline, with the exception of the ferruginous sandstone unit. Formation of these similar fabrics synmietries can not be the result of strain related to first order folding. The mica content appears to be related to the percentage of quartz lost due to pressure solution as a result of strain; the more mica present, the less quartz was lost. Calculations based on the shape of initial grains suggest that conservatively 30% of the quartz volume has been dissolved out of the Lorrain quartzite, and potentially migrated hundreds of meters to other members of the Huronian Supergroup as there was no meso or macroscopic evidence observed in outcrop.

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Landscape geochemical investigations were conducted upon portions of a natural uniform landscape in southern Norway. This consisted of sampling both soil profile samples and spruce tree twigs for the analysis of twelve chemical elements. These elements were cobalt, copper, nickel, lead, zinc, manganese, magnesium, iron, calcium, sodium, potassium and aluminum which were determined by atomic absorption analysis on standardized extraction techniques for both organic and inorganic materials. Two "landscape traverses" were chosen for a comparative study of the effects of varying landscape parameters upon the trace element distribution patterns throughout the landscape traverses. The object of this study was to test this method of investigation and the concept of an ideal uniform landscape under Norwegian conditions. A "control traverse" was established to represent uniform landscape conditions typical of the study area and was used to determine "normal" or average trace element distribution patterns. A "signal traverse" was selected nearby over an area of lead mineralization where the depth to bedrock is very small. The signal traverse provided an area of similar landscape conditions to those of the control traverse with significant differences in the bedrock configuration and composition. This study was also to determine the effect of the bedrock mineralization upon the distribution patterns of the twelve chemical elements within the major components of the two landscape traverses (i.e. soil profiles and tree branches). The lead distribution within the soils of the signal traverse showed localized accumulations of lead within the overburden with maximum values occurring within the organic A horizon of soil profile #10. Above average concentrations of lead were common within the signal traverse, however, the other elements studied were not significantly different from those averages determined throughout the soils of the control traverse. The spruce twig samples did not have corresponding accumulations of lead near the soil lead anomaly. This is attributable to the very localized nature of the lead dispersion pattern within the soils. This approach to the study of the geochemistry of a natural landscape was effective in establishing: a) average or "normal" trace element distribution patterns b) local variations in the landscape morphology and c) the effect of unusually high lead concentrations upon the geochemistry of the landscape (i.e. within the soil profiles and tree branches). This type of study provides the basis for further more intensive studies and serves only as a first approximation of the behaviour of elements within a natural landscape.