The structure of the northeastern Gulf of St. Lawrence, Canada: new insight from geophysical data analysis
Bibliographic record
Abstract
An improved compilation of magnetic and gravity data has been interpreted in conjunction with seismic reflection profiles to provide new information about the complex structure of the northeastern Gulf of St. Lawrence, Atlantic Canada. This region was affected by plate divergence and convergence events during the Grenville and Appalachian orogenies and the opening of the Iapetus Ocean. The Anticosti Basin, which developed as a foreland basin over the margin of Laurentia, is filled with a thick succession of Cambrian to Silurian sedimentary strata. Most of the interpreted magnetic and gravity anomalies have sources within the basement rocks, which is interpreted as Grenville crust beneath much of the study area. A V-shaped zone of lower amplitude gravity and magnetic anomalies in the center of the region is associated with a slight thickening of Cambrian to Middle Ordovician sedimentary rocks over a downthrown block of anorthositic Grenville crust, with a locally lower density and magnetization. Extensional faults bordering the zone presently display 130250 m of downthrow at basement depths, increasing to the southeast, but show no disruption of strata younger than Middle Ordovician. A magnetic low 200 km to the northeast is of similar geophysical character and is associated with a similar geological structure. Numerous NE-trending normal faults associated with segmentation of the Grenville basement are manifested in the magnetic and seismic data. Related anomaly sources are also present within the overlying Ordovician calcareous and clastic rocks that were deposited during extension associated with the onset of the Taconian orogeny. Other anomalies are associated with faulting and folding of shallower strata, and seismic data indicate that some of the NE-trending faults were reactivated as thrusts towards the close of the Taconian orogeny in the Late Ordovician. The geophysical data show no evidence of significant deformation north of the western margin of Newfoundland that would be associated with later compressive events of the Acadian orogeny.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.011 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".