Thesis (Ph. D.)--Carleton University, 1989. / Also available in electronic format on the Internet.

The Morrison deposit, located at the Levack mine in the City of Greater Sudbury, is a footwall-type Cu-Ni-platinum-group-element (PGE) deposit hosted within a zone of Sudbury Breccia in the Archean Levack Gneiss Complex beneath the North Range of the Sudbury Igneous Complex. It consists of sharp-walled, sulfide-rich veins that are enriched in Cu-Pt-Pd-Au relative to contact-type mineralization and can be subdivided based on vein geochemistry, mineralogy, texture, and morphology into a pyrrhotite-rich upper domain, a chalcopyrite-rich lower domain, and a pyrrhotite equal to chalcopyrite middle domain. All domains contain steeply to vertically dipping first-order sulfide veins, irregular and discontinuous second-order sulfide veins, and disseminated sulfides in country rocks. First- and second-order veins can be further subdivided into inclusion-free veins typically within Sudbury breccia matrix or along clast-matrix boundaries, and very irregular and inclusion-rich veins associated with leucosomes in mafic gneiss clasts and granophyric-textured dikes. First-order veins consist of pyrrhotite > chalcopyrite = pentlandite > magnetite in the upper domain, pyrrhotite = chalcopyrite > pentlandite > cubanite > magnetite in the middle domain, and chalcopyrite >> pentlandite > pyrrhotite = cubanite > magnetite in the lower domain. Second-order veins consist of pyrrhotite = chalcopyrite > pentlandite > magnetite and chalcopyrite = millerite = pentlandite in the middle domain, and chalcopyrite >> millerite, millerite > chalcopyrite, bornite >> chalcopyrite, and millerite > bornite > chalcopyrite in the lower domain. Second order veins are adjacent to and in contact with epidote, amphibole, chlorite, carbonate, quartz, and magnetite alteration minerals. Sulfide mineralization in the Morrison deposit is similar to other footwall mineralization associated with the SIC. The veins appear to have been emplaced preferentially into zones of Sudbury Breccia that were within ~400m of the basal contact of the SIC, because that lithology is more permeable and because those zones are within the thermal aureole of the cooling SIC permitting penetration of sulfide melts. The mineralogical, textural, and geochemical zoning in the chalcopyrite-pentlandite-pyrrhotite-rich parts of the Morrison deposit are best explained by partial fractional and/or equilibrium crystallization of MSS and ISS. Bornite ± millerite-rich mineralization are interpreted to have formed by reaction of residual sulfide melts with wall rocks, consuming Fe and S to form actinolitemagnetite- epidote-chlorite-sulfide reaction zones and driving the sulfide melt across the thermal divide in that part of the Fe-Cu-Ni-S system to crystallize borniteSS ± milleriteSS. Gold-Pt-Pd appear to have been more mobile than other metals, forming localized zones of enrichment, although it is not clear yet whether they were mobile as Au-Pt-Pd-Bi-Te-Sb-rich melts or aqueous fluids.

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Thesis (Ed.M.)--Boston University

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In this thesis I present the results of a periodicity study on the neutrino data collected over the span of the first two phases of SNO, at both low (1 day⁻¹ - 0.1 yr⁻¹) and high (1 day⁻¹ - 0.1 min⁻¹) frequency ranges. The high frequency study is the first of its kind, and is of particular interest in that it opens a window into the detection of solar g-mode oscillations, which have never been conclusively experimentally verified. In a data set with 7,646 neutrino candidates over a period of 698.29 live days, there was no detected high-frequency periodic signal. In addition to a wide-range, single-peak high-frequency search, I have performed a directed-region frequency analysis, and a noise-motivated broad-band analysis. All searches indicate an absence of periodicity in the 8B solar neutrino signal as measured by SNO. I have also carried out an analysis of time dependence in the context of a trigger-less burst search, with the motivation of either observing neutrinos from an optically occluded supernova, or setting an upper limit on the senstitivity of our detector for such an observation. I include discussions of backgrounds to such a search that are specific to a heavy-water Cherenkov detector such as SNO. / text

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The Garson Ni-Cu-PGE deposit is located on the South Range of the 1850 Ma Sudbury structure along the contact between the Sudbury Igneous Complex (SIC) and the underlying metasedimentary and metavolcanic rocks of the Paleoproterozoic Huronian Supergroup. It comprises four ore bodies that are hosted by E-W-trending shear zones that dip steeply to the south. The shear zones formed as south-directed D1 thrusts in response to flexural-slip during regional buckling of the SIC. They imbricated the ore zones, the SIC norite, the underlying Huronian rocks and they emplaced slivers of Huronian rocks and anatectic breccia into the overlying Main Mass norite. Coexisting garnet-amphibole pairs yielded syn-D1 amphibolite facies metamorphic temperatures ranging from ~550°C to 590°C. The shear zones were coeval with the moderately southdipping South Range and Thayer Lindsley shear zones, which formed to accommodate the strain in the hinge zone as the SIC tightened with progressive D1 shortening. The SE limb of the SIC was overturned together with the D1 thrusts, which were then reactivated as steeply south-dipping reverse shear zones during syn-D2 greenschist metamorphism.Syn-D2 metamorphic titanite yield a U-Pb age of ca. 1849 ± 6 Ma, suggesting that D1 and D2 are part of a single progressive deformation event that occurred immediately after crystallization of the SIC during the Penokean Orogeny. The ore bodies plunge steeply to the south parallel to the colinear L1 and L2 stretching mineral lineations. Ore types consist mainly of pyrrhotite-pentlandite-chalcopyrite breccia ores, but also include pyrrhotite-pentlandite-chalcopyrite disseminated sulfide mineralization in norite, and syn-D2 quartz-calcite-chalcopyrite-pyrrhotite-pentlandite iv veins. In the breccia ores, matrix sulfides surround silicate rock fragments that have a strong shape-preferred orientation defining a pervasive foliation. The fragments are highly stretched parallel to the mineral lineations in wall rocks, suggesting that the ore bodies are zones of high strain. Pyrrhotite and chalcopyrite occur in piercement structures, in boudin necks between fragments, in fractures in wall rocks and in fold hinges, suggesting that the sulfides were mobilized by ductile plastic flow. Despite evidence of high strain in the ore zones, the sulfide matrix in D1 and D2 breccia ores show little evidence of strain as they consist predominantly of polygonal pyrrhotite aggregates, suggesting that they recrystallized during, or immediately after D1 and D2. However, rare elongate pyrrhotite grains aligned parallel to S2 are locally preserved only in D2 breccia ores. Exsolution of pentlandite loops along grain boundaries of elongate pyrrhotite formed S2-parallel pentlandite-rich layers in D2 breccia ores, whereas the pentlandite loops are multi-oriented in D1 contact breccia as they were exsolved along grain boundaries polygonal pyrrhotite. Because exsolution of pentlandite post-date D1 and D2, and that individual pentlandite grains neither have a shape-preferred orientation nor show evidence for cataclastic flow, the sulfides reverted to, and were mobilized as a homogeneous metamorphic monosulfide solid solution (mss) during D1 and possibly D2. This is in agreement with predictions from phase equilibria as the average Garson composition plots within the mss field in Fe-Ni-S ternary diagram at temperatures above ~400°C. Disseminated and breccia ores at Garson have similar mantle-normalized multi-element chalcophile patterns as undeformed contact-type disseminated and massive ore, v respectively, at the well known Creighton mine in the South Range. This suggests that the Garson ores are magmatic in origin and that their compositions were not significantly altered by hydrothermal fluids and deformation. The lack of variations in Ni tenors between the disseminated and breccias ores suggest that the R-factor was not the process controlling metal tenors because the disseminated sulfides do not consistently have higher metal tenors than the breccia ore. The breccia ores are enriched in Rh-Ru-Ir and are depleted in Cu-Pd-Pt-Au, in contrast to footwall-type ore at the nearby Garson Ramp mine which is enriched in the same metals. When Ni100, Rh100, Ir100, Pt100 and Pd100 are plotted against Cu100, the breccia and footwall-type ore analyses plot along model mss fractionation and sulfide melt model curves, suggesting that these two ore types are related by mss fractionation. In summary, the Garson breccia ores are mss cumulates that settled quickly at the base of the SIC via a gravity filtration process, and were mobilized as a metamorphic mss by ductile plastic flow during D1 and D2. Despite minor local hydrothermal mobilization of some metals, the study confirms findings from other studies that highly deformed Ni-Cu-PGE deposits, such as the Garson deposit, can provide important information on the genesis of the deposits.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.