Eastern Wrangellia – A New Ni-Cu-PGE Metallogenic Terrane in North America
Bibliographic record
Abstract
Triassic ultramafic-mafic intrusive complexes along the eastern margin of “Wrangellia” adjacent the Denali fault from east-central Alaska to northern British Columbia constitutes a newly recognized Ni-Cu-PGE metallogenic terrane that can be traced for at least 600 km. These silllike intrusive centres acted as subvolcanic magma chambers that fed the extensive thick, overlying basalts and locally picritic pyroclastcs of the Nikolai Group in an oceanic plateau flood basalt setting. Confinement of the olivine-rich ultramafic sills, Ni-Cu-PGE mineralization, and more primitive coeval basalts and picrites exclusively to the eastern portion of Wrangellia is believed to be the product of melts forming in closer proximity to the hotter mantle plume tail or "axial jet" relative to the cooler more distal portions. The recent discovery of proximal, picritic volcanics with some of the larger mineralized ultramafic bodies in Alaska finally concludes the past paradox of tholeiitic parental magmas and primitive Ni-Cu-PGE ores in this terrane. The unprecedented levels of platinum group elements, the vast extent of this mineralized terrane, the temporal association with Siberian Trap magmatism, and the accompanying Noril’sk mineralizing event, suggest that mantle plume activity during the Permo-Triassic was unique with respect to the Phanerozoic record.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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 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".