Lead-isotope ratio measurements on hummock and hollow peat from Detour Lake area, Ontario
Bibliographic record
Abstract
Lead-isotope ratios determined for peat from a hummock and hollow sequence in a peatland near Detour Lake in northeastern Ontario are variable (206Pb/207Pb of 1.14 to 1.27 in peat and 1.17 to 1.19 in till) and indicate input of Pb from different sources. Although the Pb-isotope ratios show a pattern of systematic decrease during the last 100 years (206Pb/207Pb from 1.21 to 1.14), there is not a corresponding pattern of systematic change in Pb abundances. The Pb-isotope data, along with the Pb and Sc abundance data, from the hummock samples are best explained by Pb inputs from anthropogenic activities. Highest Pb-isotope ratios (206Pb/207Pb of 1.269) are found in hollow peat formed during the xerothermic period, 6500 to 4000 BP, a time when warmer and drier conditions affected most environmental systems.
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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 | 0.001 |
| Science and technology studies | 0.003 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".