The Plateau Property in central-eastern Yukon hosts extensive high grade gold mineralization within the Tintina Gold Province.  The property lies roughly 130 kilometers east of Mayo, Yukon within the Selwyn Basin on the western edge of ancestral North America.  The purpose of this study is to identify the microstructural controls on gold mineralization at the Plateau Property.

The Goldstack and Gold Dome zones of the Goldstrike Resources’ Plateau Property shows microstructural evidence of brittle-ductile deformation.  Microstructures indicate moderate temperatures during ductile deformation throughout the two zones.  Feldspars with undulose extinction, serrated grain boundaries, and subgrains indicate ductile deformation accommodated by dislocation creep.  Deformed quartz stockwork veining is evidence of continuous brittle-ductile deformation.  Quartz veins filling fractures are evidence for brittle deformation.  Crosscutting relationships of older and younger quartz veins all exhibit evidence for dislocation creep.  Other microstructures include kink banding and deformation twinning in feldspars.  Relict devitrified pseudotachylyte in multiple areas of drill core is evidence for brittle deformation associated with seismicity and is also subsequently ductilely deformed.  Abundant evidence for brittle-ductile deformation microstructures is strongly associated with increased gold mineralization at this property.

The strong dependence of gold mineralization on brittle-ductile deformation at the Plateau Property in the Yukon, has been observed by others in multiple other gold occurrences elsewhere.  Pseudotachylyte might also be found at other gold properties associated with brittle-ductile deformation.  Pseudotachylyte is characteristic of the brittle-ductile transition and can be used as a macroscopic indicator when looking for these structurally controlled gold zones.

The Albany deposit is an igneous-hosted, magmatic-hydrothermal, breccia graphite deposit located near Hearst, Ontario.  The deposit is contained within two intrusive vertical pipe structures known as the east and west pipes.  The deposit is estimated to contain 24 million tonnes of ore with an average grade of 3.98% graphite.  The east and west breccia pipes are texturally distinct and contain different graphite grades (5.60% and 2.85%, respectively).  Higher grades in the east pipe are attributed to intragranular mineralization.   Such mineralization is much less abundant in the west pipe, which dominantly contains the intergranular matrix-hosted mineralization that typifies both pipes.

A quantitative assessment of the morphology of graphite hosting breccia within the deposit is conducted by semi-automated digital image analysis using the program Image-J.  Image J is used to manipulate digital images of breccia drill core segments and produce quantitative date based on morphological attributes of the clasts.  Measured properties include: area% of fragments versus matrix; fragment orientations; fractal roughness dimension; shape descriptors; and, sorting.  Results from this analysis are used to assess the key textural differences between the east and west pipes.  The data is also compared to an existing model for breccia classification in order to hypothesize the genetic origin of the Albany breccia pipes.

Key morphological differences between the east and west pipes indicated by the analysis are shown by data regarding fragment shape and area% fragments versus matrix.  Fragments within west pipe breccia samples exhibit a higher degree of roundness and isotropy on average than those from the east pipe.  Impact erosional processes responsible for this roundness can be attributed to a higher number of fluid pulses and or higher energy brecciation during the formation of the west pipe.  These attributes are characteristic of volume expansion brecciation and fluid assisted brecciation processes.  The relatively angular nature of fragments within the east pipe suggest that it was more strongly influenced by fluid-assisted brecciation during its formation.

The most significant morphological similarities determined by analysis are sorting and orientation.  Samples from both suites exhibited very poor sorting, which is indicative of a very high degree of energy during formation associated with volume expansion brecciation.  Fragment orientation is inconsistent within east pipe breccia and absent in west pipe breccia.  Orientation in hydrothermal breccia results from veining and fragment imbrication.  The inconsistent fragment orientation within the east pipe is likely caused by increased influence of fluid-assisted brecciation processes.

The current genetic model for the Albany deposit suggests that the breccia pipes were emplaced violently within a hypabyssal environment by magmatic-hydrothermal activity and in response to a large scale depressurization event.  The hypothesized classification of the breccia derived from the data suggests that both pipes are volume expansion breccia, with characteristics of fluid assisted and corrosive wear breccia.  Volume expansion breccia is what should be expected given the parameters of the current genetic model, therefore, the evidence from this study supports the existing theory of emplacement for the Albany deposit.

The Northwestern Ontario Healthy Soils Project (NOHSP) was funded by the Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA) in 2014 and 2015 to increase the uptake of soil testing by farmers in Northwestern Ontario. In the Fall of 2014 and Spring/Summer of 2015 farmers’ fields were sampled on a volunteer basis to assess physical and chemical soil quality parameters to assist farmers in managing their soils. These attributes included loss on ignition (LOI), pH, cation exchange capacity (CEC), texture, and available phosphorous, magnesium, copper, zinc, and iron concentrations. This thesis compiles the data of the NOHSP to identify trends in soil health attributes among the Dryden, Thunder Bay and Rainy River regions. 

The Dryden soils were identified by the farmers as a major concern due to low regional crop yields and lack of fertilizer response. The soils sampled were slightly acidic with an average pH of 5.68, however both the available phosphorous concentration and the CEC were ideal for crop growth. The organic matter content is low for this region, particularly in relation to the clay content of the soil. The potassium concentrations were in excess of OMAFRA recommendations in the region. There was no relationship between CEC and the clay content (R2=0.06), despite the expectation. 

Thunder Bay region reportedly experienced fewer problems with crop yield. The regional average pH value is 5.97; just above an ideal value for crop growth. The average available phosphorous concentration, 27.48 mg/kg, for Thunder Bay was more than ideal for crop growth. The Thunder Bay soil organic matter content is also above the requirement for the average soil type at 7.03 % organic matter. 

Rainy River analyses indicated that the sampled agricultural soils were overall healthy. The pH value is within the ideal range at 6.53, and the organic matter content averages 6.11%. The Rainy River area does show a significant relationship between CEC and clay content. 

Based on the synthesis of the data, I propose that farmers in Dryden increase the organic matter content of their soils. This will prevent the current heavy clay soil from binding together further trapping nutrients and moisture, and making them unavailable to plants.

The Good Hope Carbonatite Occurrence is a recently discovered high grade niobium and phosphate occurrence located adjacent to the Prairie Lake Carbonatite Complex, approximately 45 kilometres northwest of Marathon and about 28km North of Highway 17 (49˚ 02’ N, 86˚ 43’ W).  This study focuses on the paragenesis and classification of the pyrochlore-group minerals of the Good Hope occurrence. Minerals identified include calcite (CaCO₃); ferrodolomite (CaFe(CO₃)₂); siderite (FeCO₃); apatite (Ca₅(PO₄)₃(OH,F,Cl);  ferrocolumbite (FeNb₂O₆); fersmite (Ca,Ce,Na)(Nb,Ta,Ti)₂(O,OH,F); and pyrochlore(A16-xB16O48(O,OH,F)8-y·zH20). Less common minerals include: ankerite (Ca(Mg,Fe)(CO₃)₂); synchysite (CaCe(CO₃)₂F); bastnaesite (Ce(CO₃)F); parisite (CaCe₂(CO₃)₃F₂); quartz; rutile; pyrite; magnetite; and barite. Two paragenetic varieties of carbonatite were recognized on the basis of mineral abundances and the textures. These are referred to as the pyrochlore-rich and pyrochlore-poor phases.  The difference between the two phases is interpreted to suggest that the pyrochlore-poor phase represents a later stage of crystallization. The pyrochlore in the pyrochlore-rich phase are intimately intergrown with coarse-grained apatite and are interpreted as clasts derived from early-forming cumulate. The niobium mineralization is dominated by pyrochlore, which exhibits complex replacement textures involving both fersmite and ferrocolumbite. On the basis of textural evidence a definitive crystallization order or relationship between pyrochlore, fersmite and ferrocolumbite could not be established. The pyrochlore is dominated by Na-Ca pyrochlore with minor amounts of Sr-pyrochlore present only in drill core samples. The compositions of pyrochlore show a transition from magmatic to an alteration trend with drill core samples being more altered than surface samples. The latter are considered to be dominantly of a magmatic origin, whereas the drill core pyrochlore are considered to have been affected by hydrothermal processes. Our data indicate easy ore beneficiation due to the presence of only one significant niobium-bearing phase with limited compositional variations. The pyrochlore also does not contain significant amounts of U or Th, which increases its economic potential as these elements can cause environmental concerns involving radioactive refinery residues.

The mineralogy of the Good Hope carbonatite occurrence is different to that of carbonatites occurring in the western and southern margins of the Prairie Lake Carbonatite Complex. The latter are dominated by olivine, calcite, fluoroapatite, Ti-magnetite and phlogopite-tetraferriphlogpite, with niobium mineralization dominated by include Na-Ca pyrochlore, latrappite, loparite, U-pyrochlore, Ce-pyrochlore and Pb-pyrochlore. These differences, coupled with different magnetic signature, carbonatite texture, weathering profile and distinct topography, indicate that the Good Hope carbonatite occurrence is perhaps not directly related to the Prairie Lake carbonatite rock; however, the actual genetic relationship remains unknown.

The Roby Zone of the Lac des Iles Pd-Pt-Ni-Cu-Au mine, located 90 km north-northwest of Thunder Bay, Ontario, was the initial locus of mining activity in the deposit.  A striking aspect of the deposit in the early stages of mining was the coincidence of the ore zone with hydrothermal alteration.  Based on this an investigation of fluid inclusions was undertaken to determine if any correlation existed between the Roby Zone mineralization and hydrothermal activity existed.

From a suite of samples collected during pre-and early-mining stages at the Roby Zone hand specimen were selected.  Hand specimen were selected based on the presence and abundance of transparent minerals.  The selected samples were used in the resulting fluid inclusion work.  Four distinct types of fluid inclusions were observed in the study:  Type I - single-phase liquid inclusions,Type II - two-phase inclusions (liquid + vapour), Type III - polyphase inclusions (liquid + vapour + one or more solid phases) and Type IV - CO₂ rich polyphase inclusions.

The study shows that fluids with temperatures occurring between 350°C and 480°C, and with a composition of NaCl-CaCl₂-H₂O and/or NaCl-H₂O and salinities of 11 to 20 equivalent wt% NaCl are associated with the ore zone of the Roby Zone.  It is believed that the distribution of ore is the result of hydrothermal activity from these fluids remobilizing and concentrating the base and precious metals.

Musselwhite Mine is a fly-in underground gold mine 500km north of Thunder Bay, Ontario, Canada with a main ore zone of metamorphosed and deformed banded iron formation.  Adjacent to the main ore zone metapelites and amphibolites were sampled to study the metamorphic zones and facies using stable metamorphic mineral assemblages.  The metapelite samples included garnet-biotite schist, staurolite-garnet-biotite schist, and previously undocumented, sillimanite-staurolite-garnet-biotite schist.  The amphibolite samples, grunerite schist and biotite-grunerite schist, are unusual, as typical amphibolites have stable metamorphic mineral assemblages of plagioclase-hornblende, not biotite-grunerite-plagioclase.  As metamorphism, deformation, and gold mineralization were synchronous the presence of staurolite and sillimanite provide both metamorphic and gold mineralization conditions. The metamorphic zones at Musselwhite Mine are staurolite or first sillimanite and the metamorphic facies is amphibolite.  The presence of staurolite and sillimanite, in the form of fibrolite, constrain the temperatures of metamorphism, deformation, and gold mineralization to 500-690ºC. 

For more details about this thesis contact Dr. Mary Louise Hill

This thesis examines the structural and stratigraphic relationships between an Archean clastic sequence of "Timiskaming-like" sedimentary and volcanic rocks and the adjacent Keewatin volcanic terrace.  Field and laboratory studies have shown that mylonitic rocks mark the sheared northern and southern boundaries of the sequence.  Similar clastic sequences are exposed to the west.  The intervening volcanic terrane is characterized by strongly sheared rocks.  The strike of these shear zones closely parallels the boundary shears of the clastic sequence, suggesting that all shear zones are related and form a large, east-west trending major zone of dislocation.  A faulted intrusive contact marks the contact with a granite to the south.  Proterozoic sedimentary rocks are exposed to the southeast and unconformably overlie the Archean rocks.

The rocks of the clastic sequence are cut by a pervasive, east-west striking subvertical cleavage.  Locally the rocks possess a second, northerly striking crenulation cleavage, which as resulted in the formation of kink bands, chevron folds, and minor folds in fine-grained rocks throughout the sequence.  The hinge lines of these minor folds plunge northward at moderate to steep angles.  The crenulation cleavage has not been observed in rocks of the adjacent terrane.

A model is proposed to account for the features found in these rocks.  Strike-slip motion along an irregularly oriented crustal shear zone resulted in the opening of pull-apart basins at releasing bends and uplift at restraining bends which led to local areas of high relief.  Sediments and volcanic debris filled the basin.  The crenulation cleavage is the result of complex motion and local reversals in the shear sense along portions of the fault, which caused compression in part of the basin.

The Deadhorse Creek ‘Diatreme’ is a Proterozoic vent breccia that probably formed in response to early mid-continent rifting.  Following emplacement of the breccia, the western subcomplex experienced three alteration events, producing the complex mineralogy observed in the main mineralized zone.  Each event has produced a unique mineral paragenesis and the timing of each has been deduced from both textural and compositional evidence.  While independent, these events made use of the same pre-existing fracture system along which the western subcomplex is situated.  In order, these events were: intrusion of granitic fluids, alkaline metasomatism, and thermal metamorphism due to the emplacement of the Coldwell alkaline complex.  Following the alteration events, and presumably a result of denudation, oxidization and leaching of the main mineralized zone has produced a supergene paragenesis of:  calcite, tyuyamunite, hollandite and barite.  The main mineralization zone was enriched in first- and second-row transition metals, rare-earth elements, beryllium, Th and U.  The mineralization is represented by the presence of:  aegirine-gervisite, aegirine-natalyite, barite, barylite, hollandite, coffinite, hematite, ilmenorutile, magnetite, monazite-(Ce), phenakite, pyrite, rutile, thorite, thorogummite, thortveitite, tyuyamunite, uraninite, V-crichtonite, xenotime-(Y), zircon, zircon-thorite-coffinite solid solutions and a few unnamed mineral species.  The resulting mineralogy is both unique and complex, with several rare minerals and new compositional extremes reported (i.e., Nb-V-rutile, aegirine-jervisite, aegirine-natalyite, zircon-thorite-coffinite solid solutions, Dy-xenotime-(Y), thortveitite, baotite, barylite and V-crichtonite).  In addition, unique parageneses are reported, giving further insight into the geochemistry of Be, Ba, Sc, V, Nb, Ti and Cr and conditions of formation of phenakite, barylite, thortveitite, crichtonite, ilmenorutile, barian feldspars and zircon-thorite-coffinite solid solutions.

The coaster brook trout populations in Lake Superior have supported a thriving fishery operation since early European settlement in the area.  The pressures from sport and commercial fishing combined with the habitat destruction and fragmentation associated with railroad, highway and industrial growth led to a sharp decline in coaster brook trout populations along the north shore of Lake Superior.  In an effort to restore lost habitat and aid failing fish stocks, tributary streams known to have historically provided habitat are being remediated.  The Kama Creek coaster brook trout realignment project is one such stream.

Historically, Kama Creek recorded high numbers of brook trout and provided important spawning, rearing and overwintering habitat.  The construction of the railroad in 1962 led to a loss of 600 metres of habitat when the stream was straightened, and the culvert became perched.  The realignment of the creek to its original configuration remedied both problems within the stream.

In order to determine the success of the remediation efforts and to determine what, if any work will be required in the future, water loss and sediment transport were examined during the months of April to August 2014.  The data collected during this period indicates little to no water loss to the old channel or groundwater table and a significant amount of sediment transport within the stream which has damaged the intended design of the stream.  Future work should aim to remedy the construction of the stream to better reflect the environmental and physical conditions of Kama Creek and ensure a stable structure can be maintained.

The Anderson Lake Pegmatite is a N-S trending, S-type granitic pegmatite derived from the Hilma Lake Granite within the Quetico Basin of the Superior Province.  It is composed of potassium feldspar – muscovite – quartz – beryl – and molybdenite with accessory ferrocolumbite, apatite and garnet. The pegmatite is crosscut by later vuggy quartz veins which occasionally host amethyst. The molybdenite within the pegmatite is syngenetic and occurs directly within quartz rich areas of the pegmatite, as well as within late stage dark gray quartz veins which crosscut the pegmatite, and in fractured surfaces of the pegmatite with ferrimolybdite. 

The molybdenite occurs as coarse-grained euhedral florets, as well as pod-like aggregates within quartz rich pods of the pegmatite. There are three main trenches along the pegmatite and the molybdenite is most abundant in Trench A, with minor occurrences in Trench B and Trench C. Within Trench C, ferrimolybdite is present within fractures hosting molybdenite. The pegmatite is roughly N-S trending along the contact between the host metasedimentary rocks and the Hilma Lake Granite. The Anderson Lake pegmatite is classified as a molybdenite-bearing Nb-Be tabular pegmatite (beryl-ferrocolumbite). Re-Os dating of the molybdenite from the pegmatite produced an age of 2689 ± 12 Ma, which predates much of the plutonism, metamorphism and subsequent pegmatite injections within the Quetico Basin. 

The associated Hilma Lake granite is classified within this study as an equigranular, coarse-grained monzogranite to syenogranite, containing plagioclase – potassium feldspar – quartz – biotite – muscovite – titanite – garnet – and apatite. The biotite is heavily altered to chlorite with magnetite inclusions between the sheets of the biotite. When plotted on a viii tectonic discrimination diagram (Rb vs. Y + Nb), the Hilma Lake Granite plots within the volcanic arc granite field. This would be expected had they formed during the subduction and transpression of the Wawa Terrane beneath the Wabigoon Terrane, when the Quetico was an accretionary complex composed of sediments derived from the volcanic arcs to the north and south.