10 resultados para Folding coadjuvant

em Brock University, Canada


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330 km 2 of the easter-n part of the Archean Manitou Lakes - Stormy Lake metavolcanic - metasedimentary belt have been mapped and sampled. A large number of rocks ~.vere analyzed for the major and trace constituents including the rare-earth elements (REE). The Stormy Lake - Kawashegamuk Lake area may be subdivided into four major lithological groups of supracrustal rocks 1) A north-facing mafic assemblage, consisting of pillowed tholeiitic basalts and gabbro sills characterized by flat REE profiles, is exposed in the south part of the map area and belongs to a 8000 m thick homoclinal assemblage outside the map area. Felsic pyroclastic rocks believed to have been issued from a large central vent conformably overlie the tholeiites. 2) A dominantly epiclastic group facing to the north consists of terrestrial deposits interpreted to be an alluvial fan deposit ; a submarine facies is represented by turbiditic sediments. 3) The northeastern part of the study area consists of volcanic rocks belonging to two mafic - felsic cycles facing to the southuest ; andesitic flows with fractionated REE patterns make up a large part of the upper cycle, whereas the lower cycle has a stronger chemical polarity being represented by tholeiitic flows, with flat REE, which a r e succeeded by dacitic and rhyolitic pyroclasti cs. iii 4) A thick monotonous succession of tholeiitic pillmled basalt f lows and gabbro sills with flat REE represent the youngest supracrustal rocks. TIle entire belt underwent folding, faulting and granitic plutonism during a tectono-thermal event around 2700 Ma ago. Rocks exposed in the map area were subjected to regional greenschist facies metamorphism, but higher metamorphic grades are present near late granitic intrusions. Geochemical studies have been useful in 1) distinguishing the various rock units ; 2) relating volcanic and intrusive rocks 3) studying the significance of chemical changes due to post magmatic processes 4) determining the petrogenesis of the major volcanic rock types. In doing so, two major volcanic suites have been recognized : a) a tholeiitic suite, mostly represented by mafic rocks, was derived from partial melting of upper mantle material depleted in Ti, K and the light REE ; b) a calc-alkalic suite which evolved from partial melting of amphibolite in the lower crust. The more differentiated magma types have been produced by a multistage process involving partial melting and fractional crystallization to yield a continuum of compos i t i ons ranging from basaltic andesite to rhyolite. A model for the development of the eastern part of the Manitou Lakes - Stormy Lake belt has been proposed.

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The Rankin Inlet area, on the west shore of Hudson Bay in the Northwest Territories, is in the Churchill Structural Province. Metamorphosed volcanic and sedimentary rocks, previously mapped as Archean and part of the Kaminak Group, underlie most of the area. The Rankin Inlet Group consists of greywacke, with minor conglomeratic greywacke, quartzite and dolomite, overlain by massive and pillowed basaltic flows. Gabbro sills intrude the sediments near the base of the volcanic sequence and three serpentinite sills outcrop at the base of the volcanic sequence. The sediments are in fault-contact with quartz monzonite to the south and were intruded by granitic rocks to the northwest. Two periods of folding were defined by the mapping. The first generation folds are recumbent isoclinal folds, with northwest-trending and northeast-dipping axial planes, formed through gravitational sliding. The second generation folds are symmetrically disposed about the axis of the granitic intrusion and have east-southeast trending and nearly vertical axial planes. Whole-rock analysis of 64 rock samples indicates that metasomatic alteration accompanied the intrusion of both the granitic rocks and the serpentinite. The volcanic rocks, gabbro and serpentinite were derived from a magma of oceanic tholeiitic affinities. The stratigraphic sequence and chemistry of the volcanic rocks of the Rankin Inlet Group indicate that this assemblage is correlative with the Hurwitz Group rather than the Kaminak Group and is therefore Aphebian in age.

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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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The Horwood Peninsula - Gander Bay area is located at NE Newfoundland in the Botwood Zone (Williams et a1., 1974) or in the Dunnage Zone (Williams, 1979) of the Central Mobile Belt of the Newfoundland Appalachians. The area is underlain by Middle Ordovician to possible Lower Silurian rocks of the Davidsville and Indian Islands Groups, respectively. Three conformable formations named informally : the Mafic Volcanic Formation, the Greywacke and Siltstone Formation and the Black Slate Formation, have been recognized in the Davidsville Group. The Greywacke and the Black Slate Formations pass locally into a Melange Formation. From consideration of regional structure and abundant locally-derived mafic volcanic olisto- 1iths in the melange, it is considered to have originated by gravity sliding rather than thrusting. Four formations have been recognized in the Indian Islands Group. They mainly contain silty slate and phyllite, grey cherty siltstone, green to red micaceous siltstone and limestone horizons. Repetition of lithological units by F1 folding are well-demonstrated in one of formations in this Group. The major structure in this Group on the Horwood Peninsula is interpreted to be a synclinal complex. The lithology of this Group is different from the Botwood Group to the west and is probably Late Ordovician and/or Early Silurian in age. The effects of soft-sediment deformation can be seen from the lower part of the Davidsville Group to the middle part of the Indian Islands Group indicating continuous and/or episodic slumping and sliding activities throughout the whole area. However, no siginificant depOSitional and tectonic break that could be assigned to the Taconian Orogeny has been recognized in this study. Three periods of tectonic deformation were produced by the Acadian Orogeny. Double boudinage in thin dikes indicates a southeast-northwest sub-horizontal compression and main northeast-southwest sub-horizontal extension during the D1 deformation. A penetrative, axial planar slaty cleavage (Sl) and tight to isocJ.ina1 F1 folds are products of this deformation. The D2 and D3 deformations formed S2 and S3 fabrics associated with crenulations and kink bands which are well-shown in the slates and phyllites of the Indian Islands Group. The D2 and D3 deformations are the products of vertical and northeast-southwest horizontal shortening respectively. The inferred fault between the Ordovician slates (Davidsville Group) and the siltstones (Indian Islands Group) suggested by Williams (1963, 1964b, 1972, 1978) is absent. Formations can be followed without displacement across this inferred fault. Chemically, the pillow lavas, mafic agglomerates, tuff beds and diabase dikes are subdivided into three rock suites : (a) basaltic komatiite (Beaver Cove Assemblage), (b) tholeiitic basalt (diabase dikes), (c) alkaline basalt (Shoal Bay Assemblage). The high Ti02 , MgO, Ni contents and bimodal characteristic of the basaltic komatiite in the area are comparable to the Svartenhuk Peninsula at Baffin Bay and are interpreted to be the result of an abortive volcano-tectonic rift-zone in a rear-arc basin. Modal and chemical analyses of greywackes and siltstones show the trend of maturity of these rocks increasing from poorly sorted Ordovician greywackes to fairly well-sorted Silurian siltstones. Rock fragments in greywackes indicate source areas consisting of plagiogranite, low grade metamorphic rocks and ultramafic rocks. Rare sedimentary structures in both Groups indicate a southeasterly provenance. Trace element analyses of greywackes also reveal a possible island-arc affinity.

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The prediction of proteins' conformation helps to understand their exhibited functions, allows for modeling and allows for the possible synthesis of the studied protein. Our research is focused on a sub-problem of protein folding known as side-chain packing. Its computational complexity has been proven to be NP-Hard. The motivation behind our study is to offer the scientific community a means to obtain faster conformation approximations for small to large proteins over currently available methods. As the size of proteins increases, current techniques become unusable due to the exponential nature of the problem. We investigated the capabilities of a hybrid genetic algorithm / simulated annealing technique to predict the low-energy conformational states of various sized proteins and to generate statistical distributions of the studied proteins' molecular ensemble for pKa predictions. Our algorithm produced errors to experimental results within .acceptable margins and offered considerable speed up depending on the protein and on the rotameric states' resolution used.

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Presented at Brock Library Spring Symposium 2015: What's really going on?

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Pair of photographs, 17 ½ cm x 12 cm of William Woodruff, son of Ezekiel and a 17 ½ cm x 12 cm photograph of Margaret Clement Woodruff in a folding silver frame. These photographs were described by R. Band in 1990 – description is included.

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Artist’s rendering in colour of Isobel Price in an oval frame with a hook at the top and a section at the back which contains a lock of hair. This painting was done by Gerald Sinclair Hayward who was a renowned artist whose work was displayed at an exhibition in New York in 1899. He painted Theodore Roosevelt, William K. Vanderbilt and members of the ruling families of Britain, Germany and Russia. The frame is enclosed in a folding case lined with velvet and silk. The silk is quite worn. The outside of the case appears to be leather and has a stand for setting it upright. It closes with a metal latch. This is accompanied by a note by R. Band.

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Two black and white photographs in an ornate, folding silver case measuring 6 cm x 4 cm (when folded). This case contains two 4 ½ x 3 ½ photographs. One photograph is of Percy Carruthers Band and the other is Robert Band as a young man.

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Light brown sediment with clasts ranging from small to medium in size. The clast shape ranges from sub-angular to sub-rounded. Lineations are abundant throughout the sample. Light folding structures can also be seen in this sample. There are minor amounts of grain crushing/stacking also present.