Continents never forget: seismological record of lithospheric deformation 1 billion years ago
Bibliographic record
Abstract
Abstract A seismic array extended from the Grenville Province into the Abitibi and Opatica subprovinces of the Superior Province, Canada. We use P-to-S converted waves in seismograms of distant earthquakes to probe boundaries in seismic properties, and demonstrate the presence of a prominent seismic feature that dips NNW into the mantle beneath the Grenville Front. We use two variants of receiver function (RF) analysis, a common conversion-point (CCP) imaging that combines seismic signals from multiple paths connecting sources and receivers, and harmonic decomposition of RF data that separates signals according to their direction in the cone of paths from which the signals have come. CCP images show the crust beneath the Grenville Province to be thicker than beneath the Superior Province, and identify a NNW-dipping boundary beneath the Grenville Front. Harmonic RF analysis shows that this feature is associated with seismic anisotropy in upper-mantle peridotite, and that this anisotropic feature extends to depths of at least 70 km. We interpret the feature as the result of a NNW-dipping shear zone formed within the mantle lithosphere during the Grenvillian continental collision. It could have accommodated internal deformation within Laurentian lithosphere or, more speculatively, mark the contact with the impacting Amazonian lithosphere.
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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 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".