Physical modelling of bedrock brecciation by ice segregation in permafrost
Bibliographic record
Abstract
Abstract The lower half of a large block of moist chalk was maintained at subzero temperatures while the upper half was cyclically frozen and thawed, simulating 19 seasonal temperature cycles in an active layer above permafrost. During the experiment, the rock surface heaved vertically by at least 34.7 mm. Sixty‐one percent of the heave occurred during freezing periods, and is attributed primarily to ice segregation accompanying upward freezing from the permafrost table during the early stages of simulated winters. Thirty‐nine percent of the heave occurred during thawing periods, and is attributed to ice segregation in the frozen rock beneath the thaw front during the mid to late stages of simulated summers. By the end of the experiment, the middle horizon of the chalk, representing the upper part of the simulated permafrost and the basal part of the active layer, had become strongly brecciated and rich in segregated ice. The style of brecciation has similarities with that in perennially‐frozen limestone, sandstone and shale in Svalbard and Canada, and chalk frozen during Quaternary cold stages in France and England. These similarities suggest that ice segregation during perennial and seasonal freezing is an important process of weathering and coarse‐sediment supply in areas of frost‐susceptible bedrock. Copyright © 2001 John Wiley & Sons, Ltd.
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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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".