Accretion-related metamorphism of the Metchosin Igneous Complex, southern Vancouver Island, British Columbia
Bibliographic record
Abstract
The metamorphic history of the volcanic sequence of the Metchosin Igneous Complex (MIC), an Eocene ophiolite exposed on southern Vancouver Island, British Columbia, Canada, was studied to examine the roles of seafloor and accretion-related processes. Metamorphic facies in the volcanics vary from prehniteactinolite assemblages in the east to greenschist and amphibolite assemblages in the west. In the east, metamorphism is typified by chlorite ± prehnite ± epidote ± actinolite assemblages that fill vesicles and replace interstitial material; plagioclase is variably albitized, and clinopyroxene is relatively fresh. In the west, the common groundmass assemblage is amphibole + epidote ± chlorite. These assemblages and chlorite geothermometry show a regional eastwest gradient of ∼510 °C/km that is oblique to the volcanic stratigraphy. The regional metamorphic facies distribution for the MIC volcanics is not consistent with seafloor hydrothermal metamorphism documented for ocean crust from mid-ocean ridges, ocean islands, or island arcs. We speculate that underthrusting of the MIC beneath the Pacific Rim Terrane led to the regional metamorphism of the MIC, and that the change in metamorphic grade from east to west results from regional tilting of the complex, perhaps by orographic effects, during or after accretion.
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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 | 0.002 |
| 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".