Geological and mineralogical surveillance of metallurgical test work was conducted on reject from the Samapleu Deposit under exploration by Sama Resources Inc., in Cote D’Ivoire.  The grade of the rejects are 2810 ppm Ni and 2520 ppm Cu. Metallurgical testing yielded recoveries of 91% Copper and 71% Nickel, and respective grades of 18200 ppm and 16400 ppm for the rougher concentrate of a one stage flotation after milling to a P20 of 27 µm, a P50 of 59 µm and a P80 of 87 µm.  The milled reject was subject to testing on a Wifley shaking table and yielded 28% recovery at a grade of 9160 ppm for nickel and 18% recovery at 5100 ppm for copper concentrates.  Geological testwork involved conducting optical microscopy on metallurgical samples as well as characterizing the wall rocks. X ray diffraction and electron microscopy were used as to enhance knowledge of minerals.  The reject was websteritic with an approximate grade of 40% enstatite with minor blue green clinoamphiboles of either pargasitic, edenitic or magnesiohastingsitic composition and deep green clinoenstatite.  Mineralization was determined to be in discrete grains or along cleavage faces.  Assemblage was predominantly pyrrhotite with minor pentlandite and fine-grained flaky chalcopyrite, some fine-grained magnetite was present.  Tabling brought a form of sorting of minerals in specific size ranges and floatation favored the fine over milled chalcopyrite.  Results of experimentation suggested that flotation is a suitable beneficiation treatment for this ore.  Gravity based tabling yielded poor results in both grade concentration and recovery and is not a recommended concentration method for this ore.

Diamondiferous intrusive lamprophyric dykes have been identified North of Lake Superior, near Marathon, Ontario. The Madonna Dyke is a diamondiferous occurrence that lies within the Superior Province within a region host to multiple alkalic and carbonatitic complexes, many of which are linked to the intrusive activity resulting from the Midcontinent rifting event at 1.1 Ga.The Madonna Dyke is a hypabyssal rock with medium- to fine-grained phenocrysts of pseudomorphed olivine, spinel, pyroxene, and amphibole set in a dark green to black altered groundmass of mainly calcite after melilite, REE-poor apatite, phlogopite and spinel. Pseudomorphed olivine occurs as microphenocrysts, phenocrysts and rare macrocrysts replaced by serpentine, magnetite and calcite. A few fresh olivine macrocrysts show mantle compositions ranging from Fo₉₁ to Fo₉₂. Clinopyroxenes are aluminous diopside with Al₂O₃ ranging from 3.11 to 14.47 wt.%. Groundmass mica show kinoshitalite – phlogopite compositions with up to 4 wt.% BaO and 20.9 wt.% Al₂O₃. Spinel-group mineral compositions follow Magnetic Trend #2 – the Titanomagnetite Trend, where spinels range in composition from aluminous magnesian chromites to titanian magnesian chromites to titanian chromites to members of the ulvöspinel-magnetite series. Spinel-group minerals occur as red chromium spinel phenocrysts to macrocrysts with magnesium-rich cores and iron-rich rims, often associated with olivine phenocrysts and macrocrysts. They also occur as fine-grained opaque groundmass titanomagnetites with altered cores, and as reaction products forming a necklace texture around olivine. Atoll spinels are present. Although the Madonna Dyke shows some textural and petrogenetic features of kimberlites, the mineralogy, including the presence of calcite after melilite and amphibole, are analogous with an ultramafic lamprophyre of Alnöitic affinity.

The lithologic unit known as the “porphyry” at Geraldton, Ontario is host to widespread gold mineralization, and yet its origin is poorly understood.  The porphyry occurs within the Beardmore-Geraldton greenstone belt in the Superior Province of the Canadian Shield.  Samples from the porphyry contain approximately 1mm porphyroclasts of plagioclase within a groundmass composed of approximately 0.1mm quartz, plagioclase, and muscovite grains.  The plagioclase porphyroclasts commonly have asymmetrical tails, and muscovite crystals tend to bend around the porphyroclasts.  Undulose extinction and subgrain boundaries indicate dislocation creep in quartz. Plagioclase commonly contains deformation twins.  The porphyry also has a well-developed foliation defined by parallel alignment of muscovite.  The microstructures are typical of a mylonite.  The porphyroclasts give a minimum original grainsize of approximately 1mm for the protolith.  Based on microstructural analysis, it appears that the most likely protolith for the porphyry is a felsic plutonic rock.  Approximately 30km east of Geraldton, near Longlac, Ontario, is a 150 km² elliptical, granitic intrusion, the Croll Lake stock. This intrusion is the nearest felsic and plutonic rock to the porphyry at Geraldton.  The Croll Lake stock is also deformed. Deformational features in quartz include undulose extinction, subgrains and serrated grain boundaries.  Plagioclase commonly contains deformation twins.  Evidence for deformation of the stock increases towards the west where it resembles the porphyry. Microstructural analysis of the porphyry and the Croll Lake stock suggest that the “porphyry” is a mylonitized fragment of the Croll Lake stock. 

NASA’s Opportunity rover landed on Meridiani Planum in the summer of 2004 with the intention of studying a rich concentration of hematite in much finer detail than what the preliminary images from the orbiting Mars Global Surveyor could possibly allow. Small, diagenetic, 4mm spherules composed primarily of hematite were discovered embedded in sand blasted bedrock, arming the scientific community with further evidence for a past presence of water on Mars (NASA, 2012). This thesis is an attempt at providing a terrestrial analogue for the formation of Martian spherules by using hematite-rich concretions observed in the minimally metamorphosed, 1.8Ga Gunflint formation as a proxy.

Approximately 60km eastbound of Thunder Bay at intersections with Mirror Lake (ML) and West Loon (WL) road lie two recently exposed, iron-oxidized grainstone outcrops standing ~2-3m vertically. Original deposition occurred in the Paleoproterozoic at 1,878Ma in a storm-dominated shallow shelf. The grainstone has a typical grey-green ankeritic to white chert colour with spherical to rhombic hematite-rich concretions averaging <2mm to 2cm in diameter present in thin layers oriented parallel to the shallowly dipping, lensy bedding or randomly distributed within lenses as independent concretions or hematitic masses. Three fundamental questions occur in response to these outcroppings: Why are these rocks so iron stained when compared with the upper cherty and shaley Gunflint at outcrops of nearby Pass Lake (PL) road?; How do these concretions form?; Is the mechanism responsible for the formation of these concretions a reasonable analogue for those observed on Mars? A scaling down approach to these queries consisted of site mapping and stratigraphic sectioning, qualitative and quantitative petrographic and SEM analysis, and quantitative geochemical analysis using data acquired from ICP-MS, ICP-AES and XRD techniques.    

It is well known that the Gunflint is high in iron that precipitated out of seawater solution as an insoluble chemical precipitate. In the studied upper cherty member, individual grainstone grains have fine, iron-rich laminae that had precipitated onto the grain surface itself or were accumulated by rolling over an Fe-rich substrate. An implicit, unconformable upper contact with the Sibley group, present at one time above the Gunflint outcrop at large would have allowed for iron-rich and potentially oxidative fluid migration into the underlying Gunflint. Large, centimeter scale, iron-rich fracture sets as well as very fine, micrometer scale capillary networks provide evidence for fluid migration. Variability in the red colouration, from blood red to maroon, can be differentiated on concentric layers of individual concretions, as well as overprinting masses, and is suggestive of multiple phases of redox fluid front migrations. It is by some combination of intrinsic and extrinsic iron combined with oxidation that gave these rocks their ultimate red colouration.

Hematite concentrations within the ML and WL outcrops are always associated with carbonates that are at varying stages of decay. These hematite-bearing carbonates have been identified through geochemical, XRD and SEM analysis to be of ferroan dolomite to ankerite in composition. They are often found nucleating on or within siliceous and hematite altered grains as rhombs, and commonly mimic the entire grain. Spherical concretions occur when several altered carbonate grains are enclosed by the growth of successive poikilitic carbonate and rarely display a distinguishable nuclei: the appearance of framboidal pyrite central to a select group of concretions and scattered within the groundmass strongly suggests the influence of bacterial sulfate reduction (BSR) on carbonate growth. The variation in size, morphology and distribution of iron-bearing carbonates within individual grainstone lenses as concretionary spheres or masses, as well as the presence of framboidal pyrites, suggests that primary, hematite-poor carbonate concretions formed in a shallow phreatic, anaerobic environment at some time after cementation.

Gunflint hematite concretions differ in several ways to those observed on Mars. Negative weathering, original iron-carbonate composition, the promotion of growth by BSR and a lesser random to common bedding parallel stratigraphic distribution define the concretions observed at the terrestrial site whereas positive weathering, jarosite-hematite-alunite composition, spherulitic growth by supersaturation of Fe-rich fluids, and non-conformable growth over all stratigraphic units define the concretions at the Martian sites (Morris et al, 2010). Concretions preserve fluid chemistry and are blueprints for flow regimes and are as such important to the evolution of water on Mars and early Earth.

A collection of fourteen samples of metal made from iron artifacts recovered from Thule Inuit and Dorset culture sites in the Canadian Arctic Archipelago was received from the Canadian Conservation Institute, Department of Canadian Heritage in order to examine the origin of the materials.  In Greenland, three sources of iron in artifacts have been determined:  terrestrial native iron, manmade iron of European origin and meteoritic iron.  Observation of polished surfaces made from the samples by reflected light microscopy revealed the presence of the Widmanstätten structure deformed in all cases by cold working, clearly indicating the meteoritic origin of all of the artifacts.  The Ni-distribution and concentration in the kamacite phase was in the classification of the meteorite thus providing strong evidence pertaining to its origin.  It is reasonable to hypothesize that the Cape York meteorite in southern Greenland is the source of iron for these artifacts. A comparison was done of the Ni-content and the bandwidth of the kamacite lamellae in the artifacts with that of the Cape York meteorite in order to precisely test this hypothesis.  1.0mm-2.0mm sized samples were taken for use in SEM-EDS analysis in order to preserve as much of the artifacts as possible.  A step-scan was performed roughly perpendicular to the kamacite taenite interface to acquire a representative sample of the artifact’s whole composition with the use of the Filomena meteorite as a standard. The deformation in the kamacite lamellae caused by the cold working of the artifacts and the small sample size prevent direct observation of the full bandwidth of the kamacite lamellae, so the bandwidth of the kamacite lamellae was calculated through the use of Goldstein’s (1965) plot of average half-width of kamacite vs the average kamacite Ni-content. The plots in this study are nearly flat, reflecting the approach to equilibrium in diffusion of Ni from kamacite lamellae.  The kamacite bandwidth as measured in SEM images and by determination from Goldstein’s (1965) figure 9 yield a range of widths of 0.042 to 0.0196mm .  These bandwidths are significantly smaller than Buchwald (1975) reported for Cape York at 1.20±0.2mm.  The bandwidths for masses other than Savik I have not been reported, but it is reasonable to expect that they would be significantly smaller and similar to the results of this study.

The Wolfcamp Lake Basalts are Midcontinent Rift-related volcanic rocks that have been linked with other MCR volcanic rocks such as the Coubran Lake Basalts and the Osler Volcanic Group along the north shore of Lake Superior. Basalts of the Wolfcamp Lake volcanic unit are exposed in two main areas bisected by the TransCanada highway northwest of Marathon, Ontario. The entire unit is approximately 2 km east-west by 4 km north-south with one large exposure northeast of the highway east of Wolfcamp Lake and a second exposure south of the TransCanada highway cropping out as large cliffs, railway cuts and outcrops on the north shore of Lake Superior near Port Munroe. Flow thicknesses are generally 2-4 m with variations present locally. The main lithology comprises basalt flows which are dominantly ophitic or sub-ophitic. The mineralogy is dominated by feldspars (primarily plagioclase), olivine and pyroxenes. Alteration minerals including hornblende, sericite, chlorite, biotite, opaques (primarily magnetite) are present in all samples at concentrations from 3% up to 40%.

All of the samples of the Wolfcamp Lake basalts show very consistent trace element geochemistry with OIB-like characteristics on primitive mantle normalised plots. They are characterised by negative zirconium, hafnium and titanium anomalies with no negative niobium anomalies observed. The Wolfcamp Lake basalts were compared to the closest volcanic rocks the Coubran Lake basalts, but differences were observed when compared to other volcanic rocks in the area.

When compared to the Coubran Lake unit the Wolfcamp Lake basalts lack the strong negative niobium anomaly displayed by the Coubran Types A and B which have been interpreted to be the result of contamination. The Wolfcamp Lake basalts also show lower Mg numbers, Ni and Cr than the Coubran Lake basalts indicating that the former are more evolved. This suggests that the Wolfcamp basalts are uncontaminated MCR magmas despite their more evolved compositions.

Throughout the Boreal Forest the bedrock of the Canadian Shield is seen on barren outcrops. These areas are classified as alternating sequences of bare rock, lichen patches and treed islands.  On the rock barrens soils are typically shallow and the freeze-thaw and wet-dry cycles that characterize these systems result in a stressful environment for the plants and animals that inhabit these systems. Despite the prominence of these systems on the landscape, particularly in Northwestern Ontario, we know very little about their structure and function. This study examines soil properties and rates of net nitrogen mineralization and net nitrification of lichen patches and treed islands on three outcrops in Northwestern Ontario.  The bedrock geology, slope and aspect of the three sites were similar among the studied sites. The plants and soils were characterized at each of the sites and soil samples were collected from lichen patches and treed islands. Soil samples were analyzed in the laboratory for pH, carbon to nitrogen ratio, nitrogen concentrations, net nitrogen mineralization and net nitrification. The lichen patches had thinner, more acidic soils with a lower carbon to nitrogen ratio when compared to the treed islands. The results from the aerobic incubation showed that there was no difference in the rates of net nitrogen mineralization and net nitrification. This could be due to immobilization from the microbial biomass. Nitrogen is one of the limiting nutrients in plant growth as it controls net primary productivity, making it essential to further investigate nitrogen processes that occur on barren outcrops.  

The Giant Dome Lithofacies of the Mosher Carbonate is located within the Steep Rock Group, 5 km north of Atikokan in northwestern Ontario. The Mosher carbonate has been studied for over a century and is one of the most well preserved Archean carbonate sequences in the world (Grotzinger, 1989). The giant domes that constitute the uppermost 70m of the 500m thick carbonate sequence are referred to as the Elbow Point Member. The giant domes are meter-sized, elongate in shape, and are internally composed of alternating crystal fan fabric and cuspate and net-like microbialite fabric. Crystal fan fabric consists of centimeter to decimeter tall radiating fans that have been argued to be originally aragonite that precipitated directly on the seafloor. Microbialites have been described by Sumner (1997) as being composed of draping, mat-like laminae, vertically oriented microbial support structures, and cement-filled voids. While both microbialite and crystal fan fabrics are common in the late Neoarchean to early Proterozoic, their occurrence with one another, and even as alternating lithologies, may be isolated to the Neoarchean. Therefore, the environmental factors that controlled the development of the giant domes, and their unusual internal composition, is not well understood.

The giant domes have been interpreted to have formed in a rimmed platform environment, where a fluctuating redox boundary resulted in the alternation in precipitation of aragonite and calcite (Fralick and Riding, 2015). Major element geochemical data suggests that the crystal fan fabric contains lower concentrations of Mn and Fe than adjacent fenestrate microbialite fabric, while Mg concentrations do not show any change in concentration. This trend may be a good indication that the primary mineralogy of the crystal fan fabric and fenestrate microbialite fabric is different. Similarly, cements that are interstitial and mantle the crystal fans contain relatively higher concentrations of Mg than the crystal fans themselves, indicating that the deposition of the fans and void-filling cements was not synchronous.

There are also features that suggest periodic subaerial exposure of the giant domes. A well-preserved desiccation surface with a typical polygonal crack pattern can be seen on a sample that in cross-section displays cuspate fenestrate fabric. The association of the support structures with the cracks that are expressed on the surface, leads to consideration of a desiccation related process in their formation. While there is an otherwise complete lack of preserved desiccation surfaces, Fe-rich red-brown surfaces that intervene between the interbedded layers of the giant domes at periodic intervals may represent desiccation or subaerial exposure surfaces that were later destroyed. Lastly, Fe- and carbon-rich dissolution surfaces separate some adjacent lithologies. These surfaces are continuous and can be seen to mark the boundary between crystal fan fabric and fenestrate microbialite fabric within certain samples. They are composed of microcrystalline quartz and zoned dolomite. The dissolution surfaces may represent hardgrounds that formed as a result of a hiatus in sedimentation and/or as result of early cementation and provided preferential fluid pathways for later silicification.

Many generations and cultures have traveled the waters and harvested the resources of Whitefish Lake, a shallow boreal lake located in northwestern Ontario.  Archaeological reconnaissance and excavations in the 1960s and 1970s uncovered the importance of the site, but could not completely unravel its mysteries.  Within the framework of a multiproxy and multidisciplinary approach, this contribution sheds light on the environment evolution of Whitefish Lake, by investigating the geochemistry of lake sediment cores and soil samples collected on and around MacGillvray Island.

At the onset of the Holocene, Whitefish Lake first existed as a multi-stage proglacial lake fed by melting ice sheets in which laminated sediments were deposited.  Climatic fluctuations during the Holocene brought varying humidity and temperature combinations, with subaerial exposure of lake bottoms during drought cycles.  With the return of cooler and moister conditions, the lake basin filled to present-day levels.  Nowadays, macrophyte beds abound on the fringes of the lake and contribute to the formation of reducing conditions below the sediment-water interface.  Sedimentation levels are very low, with sediments comprised of material derived from authigenic and allogenic organic matter as well as from erosion in the catchment area.

The archaeological record reveals that humans have occupied the Whitefish landscape for a long period of time.  However, their arrival could not be constrained geochemically with the presently available data set because the weak signal is overprinted by variations in climatic and environmental conditions.

The Coldwell Complex is situated within the Archean Schreiber-White River metavolcanic-metasediment of the Superior Province, and spanning over 25 km in diameter, is the largest alkaline intrusion in North America. There are three magmatic centers of the Coldwell Complex, which in order of intrusion are Center I, Center II and Center III. The focus of this study was to classify syenite rocks related to the three intrusive centers, and identify any REE-bearing minerals present. Fieldwork was completed along HW-17 roadcuts, and North of the highway on Canada Rare Earth claim blocks, termed the ‘Radio Hill’ occurrence. The syenites of the Radio Hill occurrence had not previously been identified due to limited access to the area. Through petrography, Highway-17 samples were classified as Center II Nepheline syenites, where the textures of amphibole, biotite, pyroxene and natrolite compared well to the nepheline syenites previously described by Mitchell and Platt (1982). Syenites of the Radio Hill occurrence were classified as Center III, specifically, ferroedenite syenites. The Radio Hill syenites show an increase in the modal abundance of quartz, and a decrease in natrolite. Compositions of the amphiboles from the Radio Hill syenites compare well with the silicic ferroedenite and hastingsitic hornblende compositions, with sample DN7b showing a trend to Na, Si, and Fe enrichment with Ca and Al depletion. Radio Hill mica have molecular end-member compositions of biotite, with Mg # ranging from 0.082 to 0.294. Radio Hill plagioclase feldspar compositions show An % from 0 to 12.04 %, representing albite to oligioclase end-members. Rare earth element minerals were described and identified from the Radio Hill occurrence using qualitative identification methods with the scanning electron microscope (SEM) at Lakehead University. Minerals found occurring in the Radio Hill syenites, in order of abundance, include Apatite (elevated La, Ce, Nd, and Th), Plumbopyrochlore ((Pb, Y, U, Ca)_2-xNb₂O₆(OH)), Ceriopyrochlore ((Ce, Ca, Y)₂(Nb, Ta)₂O₆(OH, F)), Monazite ((La, Ce, Nd)PO₄), and Fluorite.