The distribution of igneous rocks beneath Mont Mégantic (the easternmost Monteregian) as revealed by gravity
Bibliographic record
Abstract
At the surface, Mont Mégantic, the easternmost and most imposing of the Monteregian hills, is composed of 77.5% leucogranite and syenite and 22.5% gabbro. Nonetheless, the intrusion is characterized by a major positive Bouguer anomaly of +20 mGal. A computed three-dimensional gravity adumbration is consonant with the intrusion having the form of a vertical prismatic column with a flat base at a depth of 10 km. The base appears to coincide with the unconformity atop Precambrian basement rocks. Gabbro composes 96% of the adumbration. Leucogranite and syenite make up the remainder and are confined to an uppermost layer no more than about 1 km thick. The subvolcanic texture of the granite and presence of miarolitic cavities at Mégantic show the shallow level of the intrusion, the present surface perhaps having been no deeper than 1 or 2 km. This is the same as the depth of emplacement elucidated at Mont Royal, at the opposite end of the Monteregian chain, which in turn points to uniform uplift and erosion since Early Cretaceous time across the entire area, from the shield and well into the Appalachians. The mechanism of intrusion at Mégantic appears to be the same as that we proposed earlier for the eight classical Monteregians.
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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) | 0.002 | 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".