Major and Trace Element Geochemistry of Ilmenite Suites from the Kimberley Diamond Mines, South Africa
Bibliographic record
Abstract
A method was developed to distinguish between ilmenites from different mantle xenoliths found at Kimberley, South Africa: Granny Smith, dunites, orthopyroxenites, MARID and rutile-ilmenite intergrowths. The method employs a number of oxide screens based on MgO, TiO2 and Cr2O3 and systematically eliminating whole fields defined by mathematical equations. The classification scheme is useful to better understand the source of the ilmenite and has been applied to ilmenite xenocrysts from four diamond mines in the Kimberley area: Bultfontein, Kamfersdam, Otto's Kopje and Wesselton. A relationship between ilmenite chemistry and its paragenesis exists, but it is not as clear as in the Cr-poor megacrysts. A more complex process is responsible for the crystallization of ilmenite in the five different suites at Kimberley, and metasomatim by a Fe-Ti rich magma or melt, similar in composition to the parent magma of the South African megacrysts, plays an important role in ilmenite formation.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".