Characteristics and Significance of the Transition Zone in Drained Thaw-Lake Basins of the Arctic Coastal Plain, Alaska
Bibliographic record
Abstract
In the three-component conceptual model of arctic soils, the transition zone is recognized as a layer intermediate between the seasonally thawed active layer above and the stable permafrost below. Although typically frozen and therefore part of the near-surface permafrost, the transition zone episodically thaws over a time period ranging from sub-decadal to multicentennial. From an analysis of 138 pedons from the Arctic Coastal Plain near Barrow, Alaska, we were able to delineate the upper boundary of the transition zone in 78% and the lower boundary in 70% of the pedons. The transition zone exhibits the effects of cryoturbation, contains abundant redistributed organic carbon, is enriched by ice in the forms of lenses, veins, and nets (reticulate vein ice) and has abundant soil moisture. The surface (upper boundary) of the transition zone is found at an average depth of 34 ± 7 cm below the ground surface and has an average thickness of 23 ± 8 cm. We observed no significant differences in the thickness of the transition zone or the depth of its boundaries in drained thaw-lake basins ranging in age from 300 to 5500 years BP, suggesting that the processes leading to the development of this zone occur rapidly in Arctic Alaska. Recognition of the transition zone has implications for understanding pedogenic processes in permafrost-affected soils and for determining the response of near-surface permafrost to climate warming.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".