U-Pb zircon age and regional setting of the Lapeyrère gabbronorite, Portneuf-Mauricie region, south-central Grenville Province, Quebec; Radiogenic age and isotopic studies: Report 14
Bibliographic record
Abstract
High-grade tectonite bodies of the Portneuf Mauricie region were intruded by a number of small and scattered, late Grenvillian, mid-crustal gabbroic intrusions. These consist chiefly of fresh and massive gabbro and gabbronorite with well preserved igneous mineral textures, to locally recrystallized and foliated gneissic equivalents. The Lapeyrère gabbronorite is the largest of these intrusions. Uranium-lead dating of igneous zircon crystals gives a crystallization age at 1069 ± 2 Ma, close to ages previously reported for the Shawinigan gabbronorite, and two small gabbroic intrusions in Canton Taché, along the southern margin of the Lac-Saint-Jean anorthosite complex. Although modest in size, these distant intrusions signal a regionally extensive gabbroic intrusive event in the 1080 1067 Ma interval, at the onset of widespread granitoid plutonism in the south-central Grenville Province. The almost complete absence of anorthosite and the limited volume of gabbroic rocks, appear, however, to set apart this 1080 1067 Ma gabbroic pulse from those leading to classic anorthosite-mangerite-charnockite-granite (AMCG) association.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".