Bibliographic record
Abstract
Abstract Most unroofing mechanisms invoked for the exhumation of blueschist-plus-eclogite terranes, including corner-flow and extensional collapse of the orogenic wedge, predict steep unroofing paths for the deeply-buried rocks and are applicable only to unroofing from depths within the crust. Many high-P and ultrahigh-P rocks of continental affinity are derived from greater depths than this. Their lack of warming during unroofing, together with indications that they may rest directly on less deeply buried equivalents, are suggestive of shallow unroofing paths similar to those for the subduction-channel model. They are interpreted to have been emplaced by the upward extrusion of coherent slices of continental crust, bounded below by thrust faults and above by normal faults, with unroofing paths essentially reversing the original burial paths. Where continental crust has been subducted into the mantle, upward extrusion is probably driven largely by buoyancy forces, although examples of upward extrusion without subduction into the mantle indicate that buoyancy forces may not be essential. Two features in addition to buoyancy may promote upward extrusion. Slab breakoff may reduce the pull from the descending slab, and subduction-zone geometry may change as a continental margin is dragged into the subduction zone. Both features may promote the extrusion of continental crust at precisely the time at which it has been partially subducted. A close spatial relationship between a lateral ramp and a lobate zone of extruded high-P rocks in the Mesoproterozoic Grenvillian orogen indicates that lateral ramps may be important in localizing extrusion. Lateral ramps disturb the two-dimensional flow, with channelling of material into the region of the lateral ramp as it is extruded. Many exhumed ultrahigh-P terrains are associated with jogs in the trends of orogenic fronts that may reflect the presence of lateral ramps at depth. Ultrahigh-P rocks may be expected to be concentrated at such jogs, and may record the channelling in their deformation history.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.002 |
| 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".