Pseudomorphs After Titanite to Investigate Ti Mobilization in a Carbohydrothermal Pegmatite at Moose Creek, Ice River Alkaline Complex, Southeastern British Columbia, Canada
Bibliographic record
Abstract
Abstract Recent work by Piilonen et al. (2025) documents the occurrence of a dike of novel composition in the late-Paleozoic Ice River Alkaline Complex of southeastern British Columbia, Canada. The dike is notable for its mineralogical diversity (28 species documented to date), high abundance of Ti (occurring mainly as titanite, anatase, and brookite), and evidence of Ti mobilization within the close dike system. The occurrence of pseudomorphs after titanite, consisting mostly of anatase, calcite, and minor brookite, are common. These pseudomorphs are investigated here in detail to better constrain the behavior of Ti (and Nb) during, and subsequent to, dike emplacement. Pseudomorph formation is shown to occur by the reaction CaTiOSiO4 (titanite) + HCO3− + 2H2O ↔ CaCO3 (calcite) + TiO2 (anatase) + H4SiO4 + (OH)−, which follows a reaction front that systematically migrates from the edge toward the core of the primary titanite. As primary titanite breaks down, both Ti and Ca are conserved within the pseudomorph volume. Cathodoluminescence imaging (by electron microscopy) shows that growth features such as sector and oscillatory zoning in anatase are common within the samples investigated. The occurrence of such features is consistent with the growth of pseudomorphic phases having occurred in a solution into which Ti and Ca were dissolved and mobilized on the micrometer scale, immediately following initial titanite destabilization. In the later stages of dike evolution, the introduction of fluids rich in Na-Al-Si-Fe dissolve both pseudomorphic anatase and calcite, replacing them with aegirine, natrolite, and minor secondary titanite; Ti is remobilized on the centimeter-scale and partially removed from the pseudomorph volume, precipitating as secondary anatase elsewhere within the dike.
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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 | 0.001 | 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) | 0.001 | 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".