The geology, geochemistry, and magmatic evolution of the Legris Lake mafic–ultramafic complex, Ontario, Canada
Bibliographic record
Abstract
Abstract The Archean Legris Lake mafic–ultramafic complex (LLC) is spatially (~ 12 km east) and temporally (2690.59 ± 0.77 Ma) associated with the world-class Lac des Iles (LDI) palladium deposit. Modeling of whole-rock major-element compositions suggests that this complex, previously interpreted as gabbroic, is gabbronoritic in composition, adding to the likely association between LDI and the LLC. Mantle normalized trace-element profiles and modeled parental melt compositions from the cumulate lithologies indicate initial melt extraction from a metasomatized mantle source in an arc setting and subsequent crystallization of olivine, orthopyroxene, and plagioclase at depth following assimilation of SiO 2 and S from tonalitic country rock. External S assimilation contributed to sulfide saturation at depth prior to or during emplacement, but sulfide melt entrainment in intruding magmas and its retention at the site of emplacement was variable. These interpretations are supported by (1) variations in Cu/Pd ratios between PGE-rich and PGE-poor lithologies, (2) the strongly negative Eu/Eu* of paragenetically early lithologies, (3) the overlap between whole-rock εNd (T) values of LLC lithologies and Wabigoon tonalite, and (4) the positive δ 34 S and uniformly non-zero ∆ 33 S values of magmatic sulfides. During emplacement the intruding melts also assimilated metasedimentary country rock. This effect likely became more pervasive during later stages and resulted in additional melt fractionation and inheritance of the trace-element signature of the metasedimentary country rock by the intruding magmas. This assimilation does not, however, seem to have been an important driver of sulfide saturation in this system.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".