Holocene tree line, permafrost, and climate dynamics in the Nenets Region, East European Arctic
Bibliographic record
Abstract
Pollen, stomata, and macrofossils in a lake core with a basal date of 9700 14C BP were used to reconstruct past changes in climate and vegetation in the arctic tree line area, northeast European Russia. A palsa peat profile was investigated to establish a chronology of mire initiation and permafrost development during the Holocene. Macrofossils show that tree birch was present in the study area at the beginning of the Holocene and stands of spruce became established shortly thereafter. However, pollen evidence suggests that almost 400 years passed before the area was occupied by a mixed sprucebirch forest, which lasted until ca. 5000 BP. Subsequently, the area reverted to foresttundra. Paludification began ca. 9000 BP continuing at least until 5700 BP. The conditions were permafrost-free at least until 4500 BP. The latest permafrost aggradation phase is dated to the Little Ice Age. We interpret summer temperatures to have been ca. 34 °C higher between ca. 8900 and 5500 BP than at present, and the lowest temperature regime of the Holocene to have occurred between 2700 and 2100 BP.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".