Kinematic reconstruction of the South Atlantic and South Pacific regions: a new framework for Scotia Sea evolution
Bibliographic record
Abstract
The Scotia Sea formed as a Cenozoic back-arc basin in relation to the eastward retreat of the South Sandwich subduction zone. The initiation of Scotia Sea subduction is a subject of long-standing debate as the location and timing are still unclear. Here we provide a kinematic reconstruction of the oceanic basins of the South Atlantic and South Pacific, and the intra-continental deformation of southern South America and Antarctica, back to Gondwana breakup in the early Jurassic. The Cenozoic Scotia Sea is not reconstructed within the South America – Africa – East Antarctica plate circuit. This creates a framework in which the evolution of the Scotia Sea should have taken place. We use the reconstruction to assess whether, when and where, convergence occurred between South America and East Antarctica that may have initiation subduction. Marine magnetic anomalies of the South America – East Antarctica spreading system are only preserved on the East Antarctic plate in the Weddell Sea. The conjugate anomalies are necessary to assess the interaction between South America and East Antarctica. The motions predicted by the South America – Africa – East Antarctica plate circuit do not fit the preserved anomalies and we thus infer that the conjugate Weddell Sea anomalies moves as an independent plate relative to East Antarctica and South America, in a N-S direction. The predicted motion between the Weddell Sea conjugate anomalies and South America is taken up along the E-W verging southern margin of the Falkland Plateau. The relative motions predicted by this plate circuit, show that convergence occurred between Patagonia and the Antarctic Peninsula from ~70 to 59 Ma. No convergence is predicted prior to 70 Ma or after 59 Ma, and thus the convergence needed to initiate Scotia Sea subduction must have taken place within this time window along an E-W directed subduction zone ranging from between Patagonia and the Antarctic Peninsula, towards to eastern end of the Falkland Plateau.
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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".