Column Anion and Trace Element Chemistry of Apatite from Crustal Carbontite Deposits in the Grenville Province: Implications for Crustal Carbontite Genesi
Bibliographic record
Abstract
Apatite group minerals are ubiquitous in crustal carbonatites and can accommodate many elements useful for assessing the chemical provenance of these rocks.Apatite from c. 65 crustal carbonatite occurrences in Ontario, Quebec and New York were analyzed using single crystal Xray diffraction (SCXRD) to determine the column anion composition (via structure and site occupancy refinement) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to assess the trace element composition.Four trends of crustal carbonatites are apparent (Bancroft, Frontenac, Lowlands and Highlands).Most crustal carbonatite apatite is hydroxyl-rich fluorapatite of the approximate composition c. 60:40 F:OH, although chlorapatite and hydroxylapatite also occur.Apatite from the Bancroft and Highlands trends is generally less enriched in Mg and Cl but more enriched in Fe, Mn, As, U, Th and REE than apatite from the Frontenac and Lowlands trends, which commonly contains Cl to c. 10% column anion site occupancy.Plots of 1/δSr vs 1/δEu suggest evolution towards larger Sr/Eu anomalies and higher U/Th/REE concentrations possibly resulting from lower degrees of crust partial melting during the Ottawan-Rigolet transition, whereas no geographic trend in U/Th/REE concentrations and Sr/Eu anomalies is observed in Frontenac and Lowlands samples.No correlations to wall rock chemistry were observed.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".