Geochemical and Sedimentological Evidence of Paleoclimatic Change in a Late Holocene Freeze Core Record from Walsh Lake, Northwest Territories
Bibliographic record
Abstract
Climate warming in high-latitude northern environments has the potential to alter cycling of redox-sensitive elements such as arsenic (As) in lacustrine systems (MacDonald et al., 2005).The region around Yellowknife, Northwest Territories (NT), is impacted by widespread As contamination from historical gold mining and mineral processing (Jamieson, 2014).This thesis examines the past response of sediment geochemistry within Walsh Lake, NT, to paleoenvironmental changes in order to inform future mine remediation planning.Grain size, elemental geochemistry, and organic matter (OM) data preserved in an ~1100-year sedimentary freeze core record were analysed.Results suggest that (1) the cycling of trace metals (Cd, Cu, Pb, Sn, Zn) is tied to OM production and sequestration; (2) As sequestration depends on Fe and Mn (oxy)hydroxides; and (3) shifts in sediment geochemistry coincide with the Medieval Climate Anomaly and the Little Ice Age, suggesting that these climate events affected trace metal mobility in Walsh Lake.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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".