Cryptic trends in the trace element chemistry of Fe-Ti oxide minerals have been used to elucidate the magmatic processes responsible for the formation of Fe-Ti-V deposits in the Rivière Bell Complex layered mafic-ultramafic intrusion near Matagami, Quebec, Canada. Although metamorphism at greenschist-amphibolite facies conditions has modified the primary igneous compositions of magnetite and ilmenite, their Cr and V contents appear to have been unaffected. Chemostratigraphic variations of these elements in Fe-Ti oxides therefore remain valid tracers of magmatic differentiation, even in metamorphosed settings. Injections of compositionally evolved, Fe-Ti oxide-laden magma into a more primitive ferrogabbroic host are presumably responsible for sharp decreases in the Cr and V concentrations of Fe-Ti oxides that coincide with lithostratigraphic changes from predominantly disseminated gabbros to ultramafic sequences closely interlayered with massive oxides. These injections highlight the multistage magmatic history of the layered series of the Rivière Bell Complex and its vanadium ore horizons.

Masters of Science / The redistribution patterns of trace elements related to ore mineralisation in the secondary environment are the foundation of regolith exploration geochemistry. Understanding the controls of these element patterns is important for the detection of underlying ore deposits, especially in areas where bedrock is concealed by extensive regolith. The study area, which hosts PGE and gold deposits within the Stella Layered Intrusion is one such area. A major aim of this study was to use major element data to characterise the regolith materials enclosing the PGE mineralisation in the Stella Layered Intrusion to ascertain the degree of weathering that has occurred. Furthermore, the study aimed to relate the weathering patterns in regolith to the distribution of pathfinder elements of PGEs and gold in areas proximal and distal to the mineralised zones. The study was conducted using XRF data, which included major oxide and trace element data. These data were used to characterise regolith materials (scatter plots, K/Al versus Mg/Al plots) and calculating indices that determine the degree of weathering such as CIA and ICV indices as well as A-CN-K and A-CN-FM diagrams. Signatures of pathfinder/ trace elements were enhanced by hydroxylamine hydrochloride partial selective leach technique. The distribution patterns of the partial leach data were compared to the intensity of weathering and weathering products, e.g. manganese oxides, carbonates in areas proximal and distal to the ore zone. In the Serpens North Prospect, the major horizons that were identified include saprolith, stone line and aeolian sands. Incipient calcrete formation occurs in some parts of the Sirius Prospect, while in some parts, well developed, thick calcrete layers are found interlayered with the saprolith and aeolian sand.