Origin of the Tower Peak unit in the St. Cyr area, Yukon, Canadian Cordillera
Bibliographic record
Abstract
The Yukon-Tanana terrane (YTT) is a composite arc built on the rifted margin of western North America. The YTT is present in the southeastern part of the St. Cyr area in south-central Yukon, but in the northwest section the structural and lithologic relationships are poorly known. This study describes the structural geometry of the northwest section of the St. Cyr area, west of the Canol Road. The lithological, geochemical, and geochronological characteristics of the Tower Peak unit are investigated in an effort to determine its origin and terrane affinity. In the study area, the Tower Peak unit sits tectonically above a low-grade mafic-ultramafic unit. In turn, this mafic-ultramafic unit is thrust over phyllite and marble creating a composite klippe. Detrital zircons from the marble indicate a maximum depositional age of 368 Ma. This result is consistent with the footwall being part of the Devonian to Mississippian Finlayson assemblage, the oldest arc of the composite YTT. The Tower Peak unit is a massive but fractured, sub-greenschist facies metabasalt. Whole-rock and trace element geochemistry of four Tower Peak samples suggest an oceanic or island arc setting for deposition of the Tower Peak unit. Zircons separated from three samples of the Tower Peak unit give a range of U-Pb ion probe ages. Three distinct age populations exist: 600-2582 Ma, 433-303 Ma, and 140-190 Ma. The preferred interpretation is that the Tower Peak unit is Mesozoic in age and may derive from Stikinia or Quesnellia.
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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 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".