Modification of the dichotomy boundary on Mars by Amazonian mid‐latitude regional glaciation
Bibliographic record
Abstract
Restoration of the dichotomy boundary to its original position to assess its origin requires a thorough knowledge of processes responsible for its degradation and retreat. The unique fretted terrain, located along the Deuteronilus‐Protonilus Mensae northern mid‐latitude portion of the boundary, has been long held to provide clues to dichotomy degradation processes. We use new spacecraft data to show that fretted valleys display a multitude of characteristics typical of integrated valley glacial systems on Earth (multiple theater‐headed, alcove‐like accumulation areas; sharp arete‐like ridges typical of glacial erosion; converging patterns of downslope valley flow; valley lineation patterns typical of folding and shear; wrap‐around features indicative of flow around obstacles; and broad piedmont‐like lobes as the valley fill extends out into the northern lowlands). The single integrated system containing these features covers about 30,000 km2, and is one of dozens of fretted valleys along the dichotomy boundary in this region. These relationships suggest that the boundary area was subjected to very large‐scale regional glaciation during the Amazonian. Recognition and documentation of this important late‐stage process provides information critical to reconstructing the original dichotomy boundary.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".