©2014 Society of Economic Geologists, Inc. Economic Geology, v. 109, pp. 343–366 Mineralogy and Geochemistry of Cu-Rich Ores from the McCreedy East Ni-Cu-PGE Deposit (Sudbury, Canada): Implications for the Behavior of Platinum Group and Chalcophile Elemen
Bibliographic record
Abstract
Copper-rich massive sulfides are an important source of Pt and Pd in magmatic Ni-Cu-platinum group ele-ment ore deposits. At the McCreedy East deposit, Sudbury, they constitute a classic magmatic assemblage of chalcopyrite, cubanite ± pentlandite, located in sharp-walled footwall veins. These Cu-rich ores represent the subsolidus (<600°C) exsolution products of intermediate solid solution (ISS) that crystallized (950°–800°C) from a highly fractionated sulfide liquid rich in Pt, Pd, Ag, As, Bi, Cd, Pb, Se, Sn, Te, and Zn. Laser ablation-inductively coupled plasma-mass spectrometry and scanning electron microscope analyses have revealed the distribution of platinum group elements (PGE) and trace elements in these ores, which is important for a better understanding of the petrogenesis of Cu-rich sulfide deposits and to improve PGE extraction. Chalcopyrite and cubanite are the dominant hosts of Se and Sn, with Co in pentlandite. Lead is hosted by galena and Zn and Cd by sphalerite, with only a small proportion of these elements present at trace level in ISS (now equally distributed between chalcopyrite and cubanite). Platinum, Pd, Au, As, Bi, and Te, however, are not concentrated in the base metal sulfides and are accounted for almost entirely by the platinum group mineral assemblage, which is dominated by Pt-Pd-Bi-Te phases, such as michenerite [(Pt,Pd)BiTe] and froodite [PdBi2], with minor sperrylite [PtAs2] and Sn-bearing platinum group minerals
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.218 | 0.139 |
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 source (direct Gemma or distilled Codex), 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".