Potassic Rocks from the Gondwana Coalfields of India: Closing Pandora’s Box of Petrological Confusion?
Bibliographic record
Abstract
Abstract The nomenclature of potassic lamprophyres occurring in the Gondwana coalfields is discussed from a mineralogical-genetic viewpoint. The concept of a lamprophyre facies and the mineralogical character of calc-alkaline minette and peralkaline phlogopite sanidine lamproite is described. It is concluded that none of the Gondwana coalfields rocks represent calc-alkaline minettes and that there is no “minette-lamproite” association. The Gondwana potassic rocks, together with similar potassic rocks from Majhgawan and the Mainpur region, are considered to be formed from differentiates of distinct magmas formed by the partial melting of metasomatic veins in the lithospheric mantle, and as such cannot be classified using nomenclatural schemes devised for other petrological provinces. The Gondwana potassic rocks, which are the expression of potassic metasomatized lithospheric magmatism in the northern Singhbhum craton, are considered not to be Kaapvaal craton-type orangeites or Kimberley craton-type lamproites, but might be described as lamproites (var.Damodar). It is recommended that use of the terms: “minette-lamproite association”; kimberlite-clan rocks”; and “lamprophyre clan rocks” be discontinued as they serve no useful petrogenetic purpose.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".