Origin of the Sierras Pampeanas, Argentina: Flat-slab subduction and inherited structures
Bibliographic record
Abstract
Abstract The Sierras Pampeanas (27°–33°S) in South America are characterized by basementcored uplifts and shortening that occurs >500 km from the nearest convergent margin. The deformation correlates spatially and temporally with an area of flat-slab subduction of the Nazca plate in the last 10 m.y. We use two-dimensional thermal-mechanical models to study the dynamics of Pampean flat-slab subduction and the origin of the Sierras Pampeanas. Models examine a geological time from ca. 12 Ma to present day, during which time the Juan Fernández Ridge subducted beneath South America. Models show that the buoyant ridge triggers slab flattening, resulting in regional continental compression through end loading at the plate margin. Deformation in the continental interior depends on the inherited structure of the continent, where surface uplifts and shortening are concentrated at preexisting weak zones. The inboard migration of deformation is controlled by surface topography caused by the buoyant ridge rather than basal shear from the growing flat slab. Deformation occurs prior to the passage of the ridge and is inhibited when the ridge is beneath the region owing to dynamic uplift.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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".