Formation, Crystallization, and Migration of Melt in the Mid-orogenic Crust: Muskoka Domain Migmatites, Grenville Province, Ontario
Bibliographic record
Abstract
Migmatitic orthogneisses in the Muskoka domain, southwestern Grenville Province, Ontario, formed during the Ottawan stage (c. 1080–1050 Ma) of the Grenvillian orogeny. Stromatic migmatites are volumetrically dominant, comprising granodioritic gneisses with 2–5 cm thick granitic leucosomes, locally rimmed by thin melanosomes, that constitute 20–30 vol. %, and locally 40–50 vol. %, of the outcrops. Patch migmatites in dioritic gneisses form large (>10 m) pinch-and-swell structures within the stromatic migmatites, and consist of decimetre-scale, irregular patches of granitic leucosome, surrounded by medium-grained hornblende–plagioclase melanosomes interpreted as restite. The patches connect to larger networks of zoned pegmatite dykes. Petrographic and geochemical evidence suggests that the patch leucosomes formed by 20–40% fluid-present, equilibrium melting of the dioritic gneiss, followed by feldspar-dominated crystallization. The dyke networks may have resulted from hydraulic fracturing, probably when the melts reached water saturation during crystallization. Field and geochemical data from the stromatic migmatites suggest a similar petrogenesis to the patch migmatites, but with significant additions of externally derived melts, indicating that they acted as conduits for melts derived from deeper structural levels within the orogen. We hypothesize that the Muskoka domain represents a transfer zone for melts migrating to higher structural levels during Grenvillian deformation.
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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 | 0.001 |
| 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".