Varicolored Marble in the Central Metasedimentary Belt, Grenville Supergroup. II. Petrogenetic Insight from Apatite
Bibliographic record
Abstract
Abstract In the Central Metasedimentary Belt of western Quebec and eastern Ontario, dozens of fluorapatite and phlogopite deposits hosted by varicolored marble were exploited in the early 1900s. We review the literature on four occurrences: Liscombe and Silver Crater in Ontario and Seybold (Moore) and Yates in Quebec. Using the correlative microscopy approach, we report results of high-resolution scanning electron microscopy of selected areas of interest identified in large-area image mosaics of samples from Liscombe and Seybold (Moore). Textural and compositional aspects of the fluorapatite and its entrapped minerals reveal that the dikes of orange to pink calcite formed from a calciocarbonatitic melt of anatectic origin. Gravitational settling of fluorapatite occurred; the movement of slurries of crystals accounts for the striking alignment of crystals. Silicate minerals, fossil remains, and evaporitic intercalations in the precursor limestone account for the variety of minerals produced. Aggressive assimilation of fenitized host rocks by the carbonate melt was locally important. Some prisms of fluorapatite, locally gemmy and glazed, lost their sharp interfacial angles by resorption into the melt. The dikes at the Liscombe and Seybold (Moore) occurrences are poorly blended, as revealed by compositionally distinct generations of fluorapatite and monazite-(Ce), which crystallized sequentially. At the Silver Crater mine, the fluorapatite has been fenitized by alkaline fluid derived from nepheline syenite pegmatites emplaced nearby. The mantle was clearly involved in the waning stages of the Grenville cycle of continent–continent collisions.
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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 | 0.005 | 0.003 |
| Science and technology studies | 0.002 | 0.002 |
| 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".