The Monashee reflection: Re-examination of a Lithoprobe crustal-scale seismic reflection in the southern Canadian Cordillera
Bibliographic record
Abstract
The Monashee refl ection is a major crustal-scale, crosscutting refl ection that appears on two mutually perpendicular Lithoprobe seismic profi les in the southern Omineca belt of the Canadian Cordillera.It has previously been interpreted as the downplunge extension of a regional ductile thrust fault, the Monashee décollement, which is said to separate the Monashee complex from the overlying Selkirk allochthon.We reinterpret the Monashee refl ection as a shear zone with modest, normal displacement based on recent mapping, geometric analysis of the seismic profi les, and existing geochronological and metamorphic data.Recent mapping has demonstrated that this boundary is not a shear zone with thrust geometry, but rather it is a gradational boundary that has resulted from mutual folding and transposition of rocks ascribed to the Monashee complex and Selkirk allochthon.Overprinting the transition zone in different areas are three high-strain zones: the Greenbush Lake shear band zone, Slate Mountain shear zone, and a ductile shear zone associated with the Columbia River fault.We interpret these high-strain zones as segments of a single, high-strain zone that wraps around the margins of the Thor-Odin culmination.This marginal zone is a complex, outwarddipping, normal structure, which we name the Thor-Odin high-strain zone.Three alternative three-dimensional geometric models have been developed for the Monashee refl ection in order to project the refl ection to the surface.We favor a model in which the surface trace of the Monashee refl ection coincides with the Thor-Odin highstrain zone.Normal shear sense kinematics are interpreted for the Monashee refl ection based on: (1) the overall geometry and fault-drag-like relationship between the Monashee refl ection and refl ections in the hanging wall and footwall; (2) offset of metamorphic and geochronological gradients, which are consistent with an extensional zone rather than with a thrust fault interpretation; and (3) the crosscutting nature of the Monashee refl ection, which is consistent with normal structures throughout the region.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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) | 0.001 | 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".