Mesozoic drift of the Wrangellia superterrane revisited: the way forward from paleomagnetic data
Bibliographic record
Abstract
The allochthonous origin of the Wrangellia superterrane relative to North America has been established in the early days of plate tectonics using paleomagnetic and geological data. However, long-standing disagreement between paleomagnetic and structural studies on magnitude of northward translation of the Wrangellia superterrane during the Latest Cretaceous–earliest Cenozoic has cast doubt on the validity of the paleomagnetic data of the superterrane, including data from Paleozoic and Mesozoic rocks. Here, we compile all paleomagnetic data from the superterrane and present new results from uppermost Triassic limestones and lowermost Jurassic lavas of the Bonanza arc, which confirm that the Wrangellia superterrane was at those times at a much lower latitude than today, either ~25–35° North or ~25–35° South. Moreover, declinations reveal a coherent, major clockwise or counterclockwise rotation, depending on hemispheric origin. When correcting for previously documented true polar wander–the wholesale rotation of the solid Earth relative to the Earth’s spin axis–at the approximate longitude of the Wrangellia superterrane, new and existing paleomagnetic data allows for two possible scenarios of Mesozoic kinematic evolution: from 190 Ma to 80 Ma, the Wrangellia superterrane was either transported ~5000 km northward while rotating ~110° clockwise at a north-dipping subduction zone or remained at northern middle latitudes while rotating ~70° counterclockwise at a south-dipping subduction zone. The robust and reproducible Triassic–lowermost Jurassic and Cretaceous paleomagnetic data make previously speculated systematic artifacts unlikely solutions for the kinematic debate on the Late Cretaceous to Eocene tectonic history of the Wrangellia superterrane.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.000 | 0.001 |
| 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".