Petrology, geochemistry, and diabase-granophyre relations of a thick basaltic sill emplaced into wet sediments, western Montana
Bibliographic record
Abstract
The Plains Sill is a thick diabase-granophyre body that intruded the wet sediments of the Middle Proterozoic Prichard Formation of the Belt-Purcell Supergroup. The diabase is a high-iron tholeiite geochemically compatible with large-volume mantle melting in an intracratonic rift environment. Evidence of emplacement into wet sediments includes thick zones of homogenized granosediments adjacent to the sill, soft-sediment deformation at sill contacts, and sedimentary ovoid structures possibly formed by local fluidization of sediments. Utilizing sediment pore water and driven by heat from the sill, the diabase was metamorphosed during crystallization and cooling, leaving hornblende as the dominant mafic phase. Continued retrograde alteration resulted in overgrowths of secondary hornblende and variable alteration of plagioclase to epidote. A miarolitic granophyre layer, up to 150 m thick, caps the diabase and appears igneous in origin. Locally the granophyre is anomalously thick, perhaps reflecting updip migration of granophyric fluid where the Plains Sill cuts upsection through the Prichard Formation stratigraphy.
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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 | 0.000 |
| Science and technology studies | 0.000 | 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".