A textural and mineralogical study of the footwall rocks to the Sudbury Igneous Complex (North and East ranges)
Bibliographic record
Abstract
In the North and East range footwall rocks of the 1.85 Ga Sudbury Igneous Complex (SIC), quartz and plagioclase (An20-30), plastically deformed prior to the emplacement of the SIC, were thermally annealed, resulting in their replacement by aggregates of strain-free grains that coarsen towards the SIC footwall contact due to radiant heat. In the Victor footwall deposit, SIC East Range, granoblastic polygonal quartz was overprinted by dynamically recrystallized quartz, with microstructures indicative of bulging (BLG) recrystallization. Incipient melting at quartz-plagioclase interfaces in Victor footwall rocks is recorded as interstitial plagioclase seams in quartz with quartz-quartz-plagioclase dihedral angles that peak at ~40 ⁰, characteristic of wetting angles. Subsequent fluid-mediated modification of least-altered plagioclase (An20-30) generated porous albite (An0-10) through a coupled dissolutionprecipitation (CDP) mechanism, which was likely contemporaneous with the crystallization of secondary epidote-group minerals. In the Victor footwall, textures and mineral chemistry of plagioclase, epidote- and chlorite-group minerals support the notion that a relatively oxidized, acidic, Fe-bearing fluid with a temperature of ~310 – 385 ⁰C favoured quartz-plagioclase interfaces as grain-scale fluid pathways, preferentially dissolving the anorthite component of plagioclase and creating void space prior to formation of disseminated chalcopyrite proximal to massive Cu-rich sulfide veins in the footwall setting.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".