Abstract: Petrochemical evidence for autometasomatic alteration associated with fluidized emplacement of dykes in subvolcanic rhyolitic pyroclastic systems: implications for dissecting W-Mo-Bi and Sn-Zn-Cu-In ore-forming environments like Mount Pleasant, New Brunswick
Bibliographic record
Abstract
In intrusion-related environments, the emplacement of dykes can often be overlooked as part of an analysis of the ore-forming system. Although typically cryptic, fluidization is commonly the dominant process controlling the emplacement, via hydrofracturing, of these felsic dykes, based on rheologic arguments and empirical field and petrographic evidence, i.e., tuffisites. It is well known that that expansion of exsolved volatiles increases the ∆V of the system, thus enhancing the energy associated with an eruption. The decrease in geostatic pressure to sub-hydrostatic conditions within the subvolcanic magma chamber and conduit further pressure quenches these evolved low-T magmas inhibiting flow as a melt. The rhythmic textural features, various types of quench textures (i.e., skeletal growth), crystal fragmentation, autobrecciation, and conduit scaling all point to the important role of magmatic volatiles, i.e., gas-glass. Rheomorphic like features associated with continual emplacement of the tuffisite may be developed. However, subsolidus recrystallization processes, governed by the degree of undercooling below the solidus (∆T), may obscure these primary textures. The vapour associated with pyroclastic emplacement can also alter and mineralize the quenched glass entrained within it, but also along the conduit walls, by devitrification-alteration processes; this mineralization process has implications for metal vapour transport. These deuteric alteration effects resultant from F/R>>1 can obscure those same textural features that might otherwise indicate the emplacement mechanism. In addition, ore-element abundances and sulfur can be enhanced within these autometasomatically altered dykes indirectly revealing the oreforming potential of the magmatic systems from which they were derived.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".