Paleozoic Decollement Displaced the Surface Trace of Iapetus Ocean Closure in Northern Appalachians
Bibliographic record
Abstract
Abstract The northern Appalachians record accretion of Laurentia‐ and Gondwana‐derived terranes to Laurentian margin during the formation of Pangea. Terrane bounding structures, key to reconstructing this history, are poorly understood at depth. We use teleseismic receiver functions to probe the crust beneath Appalachian terranes in Québec and Maine. We identify an eastward‐dipping intra‐crustal boundary extending beneath the trace of the Iapetus Ocean closure that separates the peri‐Laurentian Dunnage and the peri‐Gondwanan Gander terranes. Systematic fabric in rocks is a likely cause of anisotropic seismic properties associated with it. Depth and position associate this boundary with a previously identified décollement separating authochtonous Laurentian basement from rocks emplaced during Pangea's assembly. Neither the décollement nor the crust‐mantle boundary under our profile change beneath the surface trace of the Iapetus Ocean closure, suggesting that it has been transported to the northwest relative to the actual boundary between mantle lithospheres of former Laurentia and Gondwana.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".