Fig. 4: Palladium deportment and trace element geochemistry of the Gonneville-Julimar PGE-Ni-Cu deposit.

A Elemental deportment into base metal sulfides (BMS). B Total PGM types by area (µm²), normalised to Pd assay per sample and summed across all samples. The “Other” category comprises PGM types that each contribute <2% of the normalised area, including Pd–Pb, Rh–As, Pt unassigned, Ag–Te, and Au. C Chalcophile element plot, normalised to primitive mantle⁷⁷ for samples with <2 %S (0.1–1.73 wt% S). D Rare earth element plot, normalised to chondrite⁷⁸ for samples with <2 %S (0.1–1.73 wt% S). E λ₀ vs. λ₂ plot, compares the REE pattern of the Gonneville SP1 and SP2 cumulates to a compilation of rock types including: Boninites from the Izu-Bonin arc⁷⁹, olivine-rich cumulates from selected orthomagmatic PGE deposits (Stillwater⁸⁰ and Bushveld⁴³), average Munro, Yilgarn and Barberton komatiite⁸¹ and MORB³⁹. λ coefficient plots are a way to visualise and compare the smoothness and shape of chondrite-normalised REE patterns. λ₀ describes average REE for each sample and λ₂ the quadratic curvature of the normalised REE pattern. A high λ₂ is attributed to strong u-shaped REE pattern, a pattern often used to describe boninite or parental orthomagmatic magma REE patterns, whereas a λ₂ near 0 represents a flat REE pattern, and a negative λ₂ represents LREE depleted rocks. Results follow methodology of O’Neill³⁹ and are calculated in BLambdaR⁸². Only samples with a chi-squared <15 are plotted. F Chondrite-normalised plot for Gonneville SP1 cumulates (light grey with circles) overlain by the calculated shape component (orthogonal polynomial function) for the SP1 normalised plot shape (dark grey), ignoring Eu. Individual λ coefficients used to describe this orthogonal polynomial, λ₀, λ₁ and λ₂, are plotted to help visualise what the different λ values describe in plot (E).