Cosmogenic nuclides 10Be and 26Al imply limited Antarctic Ice Sheet thickening and low erosion in the Shackleton Range for >1 m.y.
Bibliographic record
Abstract
Concentrations of the cosmogenic nuclides 10Be and 26Al on bedrock surfaces in the Shackleton Range, Antarctica, indicate minimum exposure ages between 3.0 ± 0.3 and 1.16 ± 0.10 Ma. The isotope data indicate that the maximum long-term erosion rate is 0.10-0.35 m/m.y., and the ratios suggest no prolonged periods of burial by cold-based ice. The findings are important because of the location of the massif close to the junction of the East Antarctic Ice Sheet and the landward extent of the Filchner Ice Shelf. These results point to three conclusions. First, the massif has not been overridden by the East Antarctic Ice Sheet during the late Quaternary. Rather, moraines 200-340 to above outlet glaciers are likely to represent the maximum thickening of the Filchner-Ronne Ice Shelf during the Quaternary. Second, the high radionuclide concentrations on bedrock surfaces, one of which is striated, suggest that some glacial landforms were created in at least Pliocene or more likely Miocene time. Third, the exceptionally low erosion rates imply that the modern cold, arid climate has persisted for millions of years. These findings provide evidence of old, stable landscapes over a wider area of Antarctica than the McMurdo Dry Valleys.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".