Till geochemical signatures of the Kiggavik uranium deposit, Nunavut
Bibliographic record
Abstract
In 2010, a drift prospecting study was initiated over the Kiggavik uranium deposit under the Geomapping for Energy and Minerals (GEM) Program. The objective of this study was to document the till geochemical signatures of the Kiggavik uranium deposit and to apply these geochemical characteristics for future exploration for buried, drift-covered uranium deposits. The study area is within the zone affected by the migration of the Keewatin Ice Divide of the Laurentide Ice Sheet. Mineralized bedrock and surface till samples (n=71) were collected directly overlying, up-ice, and at various distances (50 m, 100 m, 200 m, 500 m, 1 km, 2 km, 3 km, 5 km, and 10 km) in a fan-shaped pattern down-ice from the deposit with respect to the dominant north-northwest, northwest, and west ice-flow directions. Samples containing the highest metal contents were located directly to the west of the deposit in locally derived, basement-dominated grey till, which markedly contrasts with the regional red till dominated by material eroded from the Baker Lake and Wharton Groups of the Dubawnt Supergroup. Till geochemistry exhibits a polymetallic dispersal signature down-ice of the Kiggavik Main Zone outcrop. Uranium, Bi, Mo, Au, Ag, Co, Cs, Pb, and W range from elevated to anomalously high concentrations up to 1 km down-ice of the Main Zone and thus can be utilized as pathfinder elements. These pathfinder elements are also present down-ice from other U deposits within the Kiggavik camp, demonstrating their broad applicability to U exploration in basement rocks near the Thelon Basin. Analysis of the <0.063 mm and <0.002 mm fraction of the till matrix shows that elemental abundances are significantly greater in the finer fraction, indicating a strong geochemical partitioning based on grain size. Laboratory gamma-ray spectrometry, Pb isotopic analysis, and X-ray diffraction were conducted on the till samples. Results show that eU and Pb isotope ratios (206Pb/204Pb, 207Pb/204Pb, 207Pb/206Pb) in the till matrix share a strong correlation with U content in till and can be used as a geochemical tool for U exploration. The clay mineralogy of samples with elevated to anomalously high U is enriched in illite and kaolinite relative to quartz. Pebble lithological and Pb isotope ratio analyses have trends that can be applied to deciphering till matrix provenance.
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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 | 0.001 | 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".