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.

A study was undertaken at the Golden Patricia Mine in Northwestern Ontario to determine the applicability of geochemical sampling in the mine area.  Four different sites were mapped in detail and 50 samples were collected in total.  All diamicton samples were analyzed for whole rock composition by ICP and XRF, and for gold values by fire assay/AAS.  The major sediment cover in the area is flow diamiction with isolated areas of locally derived diamicton.  The depositional environment is thought to be a proglacial setting, dominated by massive debris flows.  The flow material is poorly-sorted and does not indicate any noticeable geochemical trends which would suggest the presence of a glacial dispersal train.  All data supports the conclusion that geochemical sampling in the area would not prove useful as an indicator of possible up-ice source of economic mineralization.

Rocks of the Coldwell alkalic complex have intruded metasedimentary and metavolcanic rocks of the Schreiber-White Lake greenstone terrain.  The complex is believed to be the product of three intrusive magmatic episodes.  The oldest episode is characterized by gabbro and augite syenite and is exposed at the southwest margin of the complex.

The intrusion of the two units has produced a thermal metamorphic aureole that attains pyroxene hornfel facies at the contact with the gabbro.  The gabbro unit shows evidence of deformation resulting in cataclasis and recystallization of the feldspar.  This has produced a protoclastic to porphyroclastic texture.  The syenite is the later unit and has intruded the gabbro.

Within the two units is found a relatively complex suite of dyke rocks showing a complex intrusive history.  The most common dyke rock is lamprophyre.  This can be broken down into three types which represent approximately four periods of intrusion.  The youngest set is characterized by having "phenocrysts" of resorbed quartz.  The quartz may either represent high-pressure phenocrysts or xenocrysts.

The study area is contained entirely within the Quetico Subprovince (of the Superior Province, Canadian Shield) in which a metasedimentary sequence is exposed.  The metasedimentary sequence consist of phyllites, wackes, sandstones, pebbly sandstones and conglomerates.  The metasediments exhibit many of the features characteristic of turbidites.  The Bouma sequence of internal sedimentary structures in the ideal turbidite bed occurs, in whole or part, throughout the area.  Many reasonably diagnostic sedimentary features suggest that the study area may be part of a large submarine fan.

Grade of the syn-tectonic metamorphism increases from north to south.  Compatible mineral assemblages characteristic of the chlorite and biotite zones of the low grade greenschist faces are defined.

Detailed structural mapping has led to the establishment of major anticline-syncline fold structures in the area.  One dominant folding episode, accompanied by a penetrative axial planar cleavage has produced easterly trending, moderately plunging fold structures.