The formation of sand bars located on a deltaic sand shelf was investigated.  The sand bars are oriented in three separate directions, one set forms parallel to the shelf edge, one set forms lengthwise in a north to south orientation, and the last set forms lengthwise in an east to west orientation.  All three sets form in a relatively small area.  The transition from deep water to the shelf occurs quickly, and the shelf edge to the shoreline remains relatively flat.  The profiles for the sand bars show that the ones that form along the edge of the sand shelf are asymmetrical.  Thus, they are probably formed by breaking waves, while the bars that form in the interior of the shelf are symmetrical and form after the breaking waves have reformed.  Examining wind direction and speed data shows that the dominant wind direction is from the west and would support the formation of waves travelling in the directions needed for the bar formation.  The grainsize distribution for the transition from deep-water to the shoreline and beach indicates a coarsening trend as the water becomes shallower.  There is a high percentage of a suspension population in the deep-water samples, while the samples obtained across the sand shelf and the beach are dominantly a saltation population.

Goldcorp’s Musselwhite mine is one of the largest gold deposits in Canada producing over 4 million ounces.  The mine consists of a variety of lithologies that are geochemically and structurally unique.  Musselwhite mine is situated within the North Caribou Greenstone Belt of the Superior Province.  The North Caribou Greenstone Belt is composed of eight metavolcanic and metasedimentary assemblages.  Musselwhite mine is located in the Opapimiskan Lake assemblage, which consists of wide range of mafic to ultramafic metavolcanic rocks. Interposed banded iron formation are found within the Opapimiskan Lake assemblage.  The mine geology is divided into five packages.  Packages consist of the Lower Basalts, South Iron Formation, Basement Basalts, Northern Iron Formation and the Upper Volcanics.  Musselwhite is an epigenetic structurally gold deposit.  Majority of gold mineralization is found in the iron formation, with two main styles of mineralization.  A quartz pyrrhotite flooding and sulphide replacement. 

The purpose of this project was to characterize pyrite and other associated sulphide minerals by examining their textural and mineralogical relationship to gold mineralization.  A total of fifteen core samples were collected by Musselwhite geologists.  The samples were prepared for petrography and SEM analysis.  Eleven of the fifteen samples were chosen for detailed analysis by the SEM.  A total of eight different lithologies were looked at in the study.  Petrographic descriptions were done for each sample.  It was found that all samples contained pyrrhotite displaying a variety of textures.  Five sample included pyrite with a range of textures.  Trace sulphides included chalcopyrite and arsenopyrite.  It was determined that gold was only correlated with pyrrhotite and quartz in this study.  There was no visible gold correlation with the pyrite.

The Paleoproterozoic (1.83 ± 0.01 Ga) Rove Formation forms the upper sedimentary unit within the Animikie Basin of the Superior Province. The Rove Formation is underlain by the Paleoproterozoic Gunflint Formation (1.878 ± 1 Ga), which contains the Sudbury Ejecta Layer near its upper contact. The ejecta layer is composed of debris from the Sudbury impact (1850 ± 1 Ma) and fragments of the Gunflint Formation.

The Rove Formation is a turbidite succession with characteristics of both turbidite system end-member models: submarine fans and ramps. Sediment input to the submarine system was from the north-north-west, with the likely source being the Trans-Hudson Orogen. The Rove Formation was deposited within a basin created by crustal subsidence associated with the Trans-Hudson Orogen, which was forming at the time of Rove Formation deposition.

This study involved the examination of approximately 1340 m of previously unexamined drill-core from five holes and reexamination of approximately 4840 m of previously examined drill-core from ten holes, totaling 6180 m of drill-core. The data from the drill-cores were used to create a series of stratigraphic diagrams in order to allow detailed architectural and sequence stratigraphic analysis of the Rove Formation to determine if the traditional submarine fan or ramp models match its stratigraphy. The drill-cores examined were drilled southwest of Thunder Bay, Ontario, in an area approximately 50 km wide between Thunder Bay and the United States Border. Architectural analysis of the Rove Formation indicated that the Rove is similar to submarine fan systems in that some well-structured depositional lobe and channel sequences are present. However, it also indicated that most of the system is more chaotic and relatively poorly structured, similar to submarine ramp systems. Furthermore, it was determined that the Rove Formation was fed by a delta coming of a braided river system and that there was not a singular point source of sediment input, as in submarine fans, but a linear sediment source and multiple feeder channels existed, similar to submarine ramp systems. Sequence stratigraphic analysis of the Rove Formation showed that there were a large number of transgressive sequences, represented by condensed shale intervals, within the Rove, indicating that relative sea-level was variable during its deposition.

While it was determined that the Rove Formation does have characteristics of both submarine fans and ramps, the architecture of the Rove does not fit either model well. This indicates that the traditional turbidite system models may be flawed and that these systems may need to be re-examined and re-interpreted using more extensive and complete data sets, similar to the data set used for this study.      

The Cerro la Mina Cu-Au-Mo porphyry-epithermal prospect is located in southern Mexico in the state of Chiapas. Discovered in 2004 as part of a larger project, referred to as the Ixhuatán Project, Cerro la Mina is one of five deposits owned and operated by joint venture partners Linear Gold Corp and Kinross Ltd. The state of Chiapas lies within a tectonically complex region marked by the triple junction of the North American, Caribbean, and Cocos plates.  It is comprised of a pre-Mesozoic metamorphic and sedimentary basement, a sequence of Mesozoic sedimentary rocks, and a sequence of volcanic and sedimentary Cenozoic rocks. Cerro la Mina is situated within a volcanic belt known as the Chiapanecan Volcanic Arc (CVA) in an area of major faulting and fracturing. Host rocks at Cerro la Mina are comprised of sequences of andesitic volcanic rocks ranging from tuff-lapilli-breccia-size fragments and coarser dacitic pyroclastic units including flows, lahars, and debris flows. The majority of these host rocks have been highly altered to the point where advanced argillic alteration has obscured any primary textures. Zircon in the host rock at Cerro la Mina has been dated at 1.01± 0.04 Ma which is younger than the surrounding rocks which generally range in age from 2.14±0.04 to 2.79±0.08 Ma.

While much work has been done on Cerro la Mina, very little has been done on the clay alteration which overprints everything. In order to better understand this alteration, a study was performed on 45 samples using x-ray diffraction, Reitvelds analysis, formamide intercalation, scanning electron microscope and acid etching. XRD revealed that the two major clays at Cerro la Mina were halloysite (7Å and 10Å) and kaolinite which were identified in 30 and 34 of the 45 samples respectively. Other clays included alunite in 12 samples, dickite in eight samples, illite in 15 samples, pyrophyllite in six samples and an unknown white clay in one sample. Halloysite (7Å and 10Å) and kaolinite were found together in 28 of the 45 samples. Twelve samples were then analyzed using the SEM and showed the presence of tubular and spheroidal halloysite as well as platy kaolinite throughout each sample. Acid etching of 21 samples revealed that feldspars at Cerro la Mina are secondary in origin.

The association of both halloysite 7Å and 10Å with minerals including quartz, alunite,
dickite, kaolinite, gypsum, and jarosite suggests a supergene overprinting of the primary mineralogy. However, the association of orthoclase, phlogopite, pyrite and molybdenite may indicate that some halloysite was formed as a result of hypogene processes.  The parent mineral subsequently altered to halloysite and kaolinite was most likely feldspar and not mica, with early formed halloysite later being converted to kaolinite. The Cerro la Mina prospect is interpreted to be a high-sulfidation epithermal deposit situated within a lithocap overtop a deeper porphyry copper system.

The 2310 Ma Kona Dolomite of Marquette, MI lies within the Chocolay Group of the Marquette Range Supergroup and has previously been correlated to the Cobalt Group of the Huronian Supergroup. The dolomitic units of the Gordon Lake Formation, Cobalt Group, are equivalent to the Kona Dolomite in Marquette and this study refers to the two dolomite units as a whole. These formations, termed the Kona Dolomite (KD) were deposited on what was a passive continental margin after the last Huronian glaciation and the Great Oxidation Event, making the KD an interesting suspect for analysis.

In order to better understand how free oxygen entered our atmosphere, sedimentological, geochemical, and isotopic techniques were utilized. It’s important to have a good understanding of the sedimentology and lithofacies before looking at the geochemistry in order to see localized depositional trends with the ocean chemistry. Thus, nine lithofacies associations (LA) have been identified in the KD based on their morphological and mineralogical differences. Each LA is indicative of its own depositional setting on a tidal flat.

The Ripples and Low Domes LA is composed of soft, centimetric, irregular, and wavy laminations of varying pink and gray carbonates- representing climbing ripples, wave ripples, and low-domal stromatolites. Lenticular and wavy bedding show bi-directional cross-stratification, a feature common in intertidal flat settings. Small Domal to Stratiform Stromatolite LA (<4cm tall) are low pustular stromatolites that have laterally continuous lamination and tend to gradually change upwards into stratiform stromatolites. These likely formed in an intertidal flat setting as they are associated with the bi-directional ripples.

Smooth to crinkly, millimetric, and relatively isopachous laminations comprise the Parallel Laminated LA. Laminations are wispy in places and contain low domes that are indicative of microbial activity and were likely situated within a pond on the intertidal flat.

Hummocky Cross-stratified (HCS) LA is composed of gray carbonate sands that have low-angle truncation surfaces and likely formed in a tidal channel environment that feed the tidal flat system. The stunning outcrop of Large Columnar to Domal Stromatolites (LCDS) stands 5 to 6m tall, and are composed of laterally continuous columnar lamination joined by cuspate depressions that gradually shift into domal stromatolites. The LCDS grew on top of the sandy HCS within the tidal channels.

Fenestral Microbialite LA show good, fairly isopachous banding with dark reddish elongated fenestrae that are discontinuous on the microscale but show low domes on a macroscale. The fenestral microbialite is similar in colour to the Bedded Siltstone and Mudstone LA as they are both composed of similar reddish-brown siliciclastics and carbonate. The latter is composed of intercalated siliciclastics, iron-rich, and iron-poor carbonate mud, and contain sub-euhedral rectangular carbonate clasts. The clasts were deposited by storm events that ripped up the fenestral microbialite in the upper intertidal flat, flooded the supratidal flat and deposited them on a sabkha.

The Subaqueous Gypsum Pseudomorph LA is composed of laterally continuous chevron textured carbonates replacing vertical gypsum crystals, while the Subaerial Gypsum Pseudomorph LA is composed of euhedral, diamond shaped pseudomorphs that lie within a very fine-grained dark purplish siliciclastic- and carbonate-rich groundmass. The former would have formed in an open water supersaturated environment, such as a pond on the sabkha, whereas the latter would have formed within the sediment in the sabkha itself.

Geochemically, these LAs are enriched in middle rare earth elements (REEs), but do not have pronounced Eu anomalies. Prior to the 2310 Ma KD, ocean chemistry was controlled by hydrothermal activity that created Eu enrichment compared to the other REEs. This contrasts with today’s oceans that are controlled by continental inflow. The absent Eu anomaly is illustrated in the REE concentrations of the LCDS and HCS LAs and represents what seems to be a turnover event from an ancient ocean system to a modern system.

Carbon isotopic ratios show an interesting trend when compared to their respective lithofacies. The δ¹³C increases from lower tidal flat to sabkha environments. This probably represents increasing evaporative loss of light CO_2. This local trend is superimposed on the beginning of the Lomagundi Event which is known as the most prolonged and largest period of carbon-13 enrichment in Earth’s history.

A potential kimberlite target known as “Target #6” has been identified 40km northwest of Marathon, ON, within the Wawa-Abitibi sub-province of the Superior Province.  Ground prospecting revealed a botanical anomaly that consists of a large semi-circular grassy area surrounded by a boreal mixed-wood forest.  A grassroots exploration program began in 2013, which has included diagnostic testing such as Soil Gas Hydrocarbon (SGH) analysis and an aeromagnetic survey, both of which showed positive indicators for the presence of a kimberlite (or related rock type).  This study utilized investigative techniques focusing on the surficial geology above this potential target to try and explain the botanical anomaly, and to further explore the geologic setting in order to better understand the occurrence.  Vegetation has been identified as Calamagrostis Stricta and Carex Utriculata, The species present in the anomaly are generally found in wet environments such as lake shores and margins of streams.  It has been shown that pH is not a control on the vegetation above the anomaly.  Grain size analysis of the soils was completed and shows indicator mineral chemistry was completed for any potential kimberlite indicator minerals, and results indicate that kimberlitic indicator minerals are not present.  It is possible that the vegetation above Target No. 6 is being directly influenced by an anomalous deposit below the sediment but the data collected in this study was unable to explain the vegetation anomaly.  The target appears to be a depression that has been filled in by sediment from a stream mouth bar, and the sediment may be acting as a vent for the deposit beneath it allowing the Soil Gas Hydrocarbons to be measured at surface.  The minerals in the surficial deposit above the target were not indicative of a kimberlite as they were likely derived from the previous glaciation event and not from weathering of the kimberlite (or other deposit) itself.

The Copper Bar Prospect, located southwest of Thunder Bay, Ontario is of interest for Ni-Cu-PGE exploration. Five historic trenches are found along the dike though there are no records of any results from them. The Copper Bar dike is a tholeiitic diabase intrusion, dominated by a sub-ophitic texture of plagioclase and pyroxene (primarily orthopyroxene). Sulphide mineralization is fairly consistent along the dike forming blebby fine- to medium-grained blebs. Fine-grained disseminations of chalcopyrite, pyrite and sphalerite are found throughout the dike. Secondary chalcopyrite mineralization is found in fractures in the more heavily altered samples. Three groupings can be distinguished petrographically and geochemically, Group one corresponding to more altered portions of the dike where complex mineralization is observed with galena, pyrrhotite, pyrite, magnetite, sphalerite, bornite, chalcopyrite, covellite, chalcocite and pentlandite with other trace sulphide mineralization. Group two represents relatively unaltered samples dominated by sub-ophitic texture. Mineralization in these samples is minimal, usually occurring as fine-grained disseminations of chalcopyrite, sphalerite and pyrite. Group three occurs as a more coarse-grained sample with overprinting blebby magnetite, pyrolusite and ilmenite phases. Generally, group three is similar to group one. Secondary pulses of magma seem to have effected the more altered samples with chalcopyrite rimming some sulphide grains and filling fractures. Overprinting sulphides and coarse- grained zones also indicate possible secondary magma pulses during emplacement of the dike. Though the dike presents favorable mineralization, low grade values were seen for Cu, Ni, Pt, Pd, Rh, Ir and Co. Partial melting and fractionation as well as failure to reach sulphide saturation sufficient to assimilate crustal sulfur are considered probable causes for the low grades observed. Positive Th and negative Nb anomalies typical of MCR-related intrusions indicate deep crustal contamination. Geochemical results also showed a strong vanadium depletion and slight titanium depletion. Group one samples showed more crustal contamination then group two, and group three had a distinct enrichment of heavy rare earth element not seen in group one or two.

The EBL 10-027 drill hole goes through the 2.94 Ga top of the Ball assemblage of the Red Lake greenstone belt, northwestern Ontario.  It reveals a succession of chemical sediments and siliciclastics that shows, for the most part, a progression from a hydrothermal signature with the formation of sulphides close to the bottom of the sequence to chemical sediments reflecting the influence of seawater at the top.  The stratigraphy is dominated by sulphides, i.e. pyrite and pyrrhotite, carbonaceous slate, magnetite iron formation and chert.  The chert varies from units roughly mixed up with siliciclastics and sulphides to chert that is nicely layered with sulphides and contorted to finely layered carbonate with dolomite crystals.

The drill hole has a true thickness of about 280 metres which allows the bottom sediments to reflect the geochemistry of deeper water hydrothermal activity with fluids rich in iron and manganese while the top is composed of carbonates that reflect the chemistry of a shallow, continental shelf environment.

The evident europium (Eu) anomaly present in the sample signifies the effect of the leaching of basalt which is interlayered with carbonate iron formation at the lowest point of the sequence.

The Wabigoon and Quetico subprovinces are east-west trending belts of metasedimentary and metavolcanic rocks located within the Superior province, the world’s largest preserved Archean craton.  The Wabigoon-Quetico subprovince boundary in the Decourcey Lake area is complex and several kilometres wide.  The 130m-long roadcut on Hwy 527 near Decourcey Lake is composed of a garnet-biotite to biotite schist with three intrusions, a pegmatitic intrusion, a felsic intrusion and a mafic dyke.  There are also several quartz-carbonate veins that have been folded and boudinaged; the folded veins crosscut the boudinaged veins that are parallel to foliation. 

In the southern portion of the outcrop, mats of fibrolite in the schist indicate peak metamorphism at amphibolite facies or higher.  However, some parts of the outcrop show evidence of overprinting retrograde metamorphism.  The amount of retrograde metamorphism increases from south to north in the outcrop.  In the southern part of the outcrop there are minimal amounts of chlorite (~1%) and the amount increases to about 30% in the north.  The chlorite replaces biotite, the main mica in the southern portion of the roadcut.  Chlorite replacing biotite is indicative of retrograde metamorphism.

Other evidence for this retrograde metamorphism is the presence of stable garnet in the southern portion of the outcrop and metastable garnet in the northern portion, indicated by euhedral unfractured crystals in the south and anhedral, fractured and separated grains in the north.

Throughout the schist, quartz with undulose extinction, irregular grain boundaries and subgrains provides evidence for deformation by dislocation creep.  In the southern portion of the outcrop, undulose extinction in feldspar indicates deformation at amphibolite facies temperatures or higher.  This higher temperature deformation of feldspar is not evident in the northern portion of the outcrop where retrograde metamorphism is more pervasive.  The pegmatite and felsic intrusions preserve evidence of deformation at the amphibolite facies or higher, including undulose extinction in feldspar and bent mica grains.

The preservation of evidence for amphibolite facies metamorphism and high temperature deformation in schist in the southern portion of the outcrop as well as in the pegmatite and felsic intrusions suggests that the Decourcey Lake roadcut is composed of metamorphosed Quetico lithologies.  Therefore, the Quetico-Wabigoon subprovince boundary lies to the north of this roadcut.  The increase in retrograde metamorphism toward the northern portion of the outcrop (in the direction of the subprovince boundary) suggests that this lower temperature metamorphism may be associated with the boundary.

The Hemlo gold deposit, Ontario, Canada is located in the Archean Schreiber-Hemlo greenstone belt, Wawa subprovince, of the Superior Province.  The deposit has been subjected to a complex history of deformation and intense hydrothermal alteration.

The host lithology to most of the gold at Hemlo is the Moose Lake Prophyry Complex (MLPC), a felsic orthogneiss, characterized by the occurrence of quartz “eyes”.  These quartz “eyes” are deformed quartz porphyroclasts.  The matrix of the MLPC is mylonitic, composed of quartz, microcline, minor biotite and white mica.  The micas define the weak to strong foliation.  Other minerals present are calcite, plagioclase, and pyrite, with trace gold, titanite and tourmaline.  The porphyroclasts of quartz range in size from 1mm to 5mm, are typically elongated to form the characteristic eye shape and rarely appear together to with feldspar porphyroclasts.

Although common in association with gold deposits, quartz “eyes” are generally rare.  An objective of this thesis is to explain the occurrence of quartz porphyroclasts in a mylonite, quartzo-feldspathic matrix.  Microscopic observations reveal the brittle deformation and alteration of feldspar porphyroclasts in spatial association with ductile deformation of quartz porphyroclasts.  Although debatable, the protolith of MLPC is generally thought to be volcanic.  After detailed examination of samples collected from the MLPC, this study concludes a plutonic origin for the quartz porphyroclasts can not be ruled out.