Petrographic and cathodoluminescence characterization of apatite from the Sue-Dianne and Brooke IOCG mineralization systems, Great Bear magmatic zone, Northwest Territories
Bibliographic record
Abstract
Apatite is the main REE-bearing phase in 19 thin sections from two mineralized systems and their host rocks, the Cu-Ag-(Au) Sue-Dianne IOCG deposit and the nearby Brooke Zone, located within the southern Great Bear magmatic zone, Northwest Territories, Canada. The thin sections show a range of IOCG-related alterations and igneous protoliths. Apatite occurs in all thin sections, in amounts ranging between traces to 5-10%. It can be divided into four populations on the basis of size, cathodoluminescence (CL) response and petrographic association: 1) small euhedral apatite (20-40 µm), occurring in clusters of 5 to 20 grains, generally free of inclusions, found in the volcaniclastic samples; 2) single apatite crystals (60-80 µm) with pitted edges, numerous fluid inclusions and sometimes monazite and hematite inclusions; 3) large single apatite crystals (100-300 µm) within epidote veins, sometimes associated with scheelite; and 4) large fractured apatite crystals (0.5 to 4 mm) with heavy hematite staining associated with hydrothermal breccias. The first 3 populations have a green to yellow CL response and the third population shows some irregular zoning. The fourth population shows a blue CL tint, with irregular green zones throughout grains or near the crystal rims. In that fourth population, mineral inclusions with an orange CL response are likely calcite. Group 3 and 4 also show an heterogeneous REE distribution within crystals under EDX. Given the overprinting of multiple alteration types in many of the specimens, additional work is needed to relate these apatite populations to specific alteration stages associated with IOCG-type mineralization. However, the presence of apatite coarse enough to be picked from glacial sediment samples and showing distinctive CL signatures in rocks related to IOCG mineralization suggests potential as an indicator mineral method.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".