Tectonic evolution and significance of Silurian Early Devonian hinterland-directed deformation in the internal Humber zone of the southern Quebec Appalachians
Bibliographic record
Abstract
In the southern Quebec Appalachians, the early tectonic history of the Laurentian margin (Humber zone) comprises foreland-propagating, northwest-directed thrust faulting, nappe emplacement, and regional prograde metamorphism in response to the obduction of large ophiolitic nappes during the Taconian orogeny. In the internal Humber zone, this event is dated at 462 ± 3 Ma (late Middle Ordovician), which is interpreted to represent the timing of near-peak Taconian metamorphism. Superimposed hinterland-directed structures are accompanied by retrograde metamorphism and consist of back thrusts and normal faults, which respectively delimit the northwestern and southeastern limbs of the Sutton and Notre-Dame mountains anticlinoria, both salient structures of the internal Humber zone of southern Quebec. Geochronologic data on the timing of hinterland-directed deformation vary from 431 to 411 Ma. Two tectonic models are presented and discussed, which may account for the Silurian Early Devonian evolution of the Laurentian margin: (1) back thrusting and syn- to post-compressional crustal extension in response to the tectonic wedging of basement-cored duplexes inducing delamination of supracrustal rocks; (2) tectonic exhumation of the internal Humber zone by extensional collapse. Evidence for Silurian Early Devonian extensional tectonism in the Humber zone provides the basement infrastructures necessary for the creation and the onset of sedimentation in the Gaspé Belt basins (e.g., Connecticut Valley Gaspé synclinorium). Several structural, metamorphic features in the internal Humber zone of the northwestern New England Appalachians yield analogous characteristics with those of southern Quebec and may have shared a similar Silurian Early Devonian tectonic evolution.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.001 | 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".