Possible role of midcrustal igneous sheet intrusions in cratonic arch formation
Bibliographic record
Abstract
Factors controlling widespread cratonic arch formation across western North America from the Early Paleozoic to the Middle Mesozoic remain poorly understood. While a number of causes, such as mantle hot spots, lithospheric contraction, mantle flow, and lithospheric flexure due to surface loading, have been suggested to explain the localized uplift of basement blocks on otherwise tectonically quiescent margins, a variety of mechanisms may be at work. Here, we test the hypothesis that seismically detected packages of discrete midcrustal igneous sheet intrusions impart rheological contrasts within the crust, which act as seeds for cratonic arch formation in the presence of weak intraplate compression, using finite element modeling of intraplate deformation. We find that the seismically resolved sills can generate significant surface uplift in the presence of modest strain rates over reasonable orogenic timescales. Cratonic arch formation would be enhanced in the presence of additional thin, seismically unresolvable sills. While midcrustal sheet intrusions may be just one of many factors influencing cratonic arch formation, their presence in northern Alberta, Canada, can help explain the asymmetric configuration of the well‐studied Peace River Arch.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.006 | 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 teacher head, 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".