Paleomagnetism of the Grum Zn–Pb–Ag deposit, Selwyn Basin, Yukon, Canada
Bibliographic record
Abstract
The Grum deposit is one of five large clastic-dominated Zn–Pb–Ag deposits in the Anvil district of the Selwyn Basin, Yukon. Grum's mineralization occurs at the contact between the late Proterozoic to Cambrian Mount Mye Formation and the Cambrian to Early Ordovician Vangorda Formation. Paleomagnetic analyses of 113 specimens from 15 mineralized sites in the Grum open pit were undertaken to date Grum's mineralization. The analyses isolated a stable characteristic remanent magnetization (ChRM), mostly by thermal and then alternating field demagnetization. The main ChRM carrier is single- or pseudosingle-domain pyrrhotite with minor magnetite that give a paleopole at 67.8°N latitude and 317.4°E longitude (radius of the cone of 95% confidence, A95 = 7.2°). The paleopole yields an age of 176 ± 12 Ma for the Grum deposit after a clockwise rotation and northward translation of the basin to best fit the North American apparent polar wander path. Thus, the Zn–Pb–Ag Grum mineralization significantly predates intrusion of the nearby mid-Cretaceous Anvil Batholith, but is coeval with widespread Early Jurassic metamorphism in the Selwyn Basin that correlates with the Early Jurassic collision of the Intermontane Belt terranes with the North America craton.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".