Phase equilibria modelling of kyanite‐bearing anatectic paragneisses from the central Grenville Province
Bibliographic record
Abstract
Abstract Kyanite‐bearing paragneisses from the Manicouagan Imbricate Zone and its footwall (high‐P belt of the central Grenville Province) preserve evidence of partial melting with development of metamorphic textures involving biotite–garnet ± kyanite ± plagioclase ± K‐feldspar–quartz. Garnet in these rocks displays a variety of zoning patterns with respect to Ca. Pseudosection modelling in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O (NCKFMASHTO) system using measured bulk rock compositions accounts for the textural evolution of two aluminous and two sub‐aluminous samples from the presumed thermal peak to conditions at which retained melt solidified. The prograde features are best explained by pseudosections calculated with compositions to account for melt loss. The intersection of isopleths of grossular content and Fe/(Fe + Mg) relating to large porphyroblasts of garnet provide constraints on the P–T conditions of the metamorphic peak. These P–T estimates are considered to be minima because of the potential for diffusional modification of the composition of garnet at high‐T and during the early stages of cooling. However, they are consistent with textural observations and pseudosection topology, with peak assemblages best preserved in rocks for which the calculated pseudosections predict only small changes in mineral proportions in the P–T interval, in which retrograde reactions are inferred to have occurred between the thermal peak and the solidus. Maximum P–T conditions (14.5–15.5 kbar and 840–890 °C) and steep retrograde P–T paths inferred for rocks from the Manicouagan Imbricate Zone are comparable with those determined for mafic rocks from the same area. In contrast, maximum P–T conditions of 12.5–13 kbar and 815–830 °C and flatter P–T paths are inferred for the rocks of the footwall to the Manicouagan Imbricate Zone. The general consistency between textures, mineral compositions and the topologies of the calculated pseudosections suggests that the pseudosection approach is an appropriate tool for inferring the P–T evolution of high‐P anatectic quartzo‐feldspathic rocks.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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
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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".