Groundwater Ages in Intertill and Buried Valley Aquifers in Saskatchewan, Canada
Bibliographic record
Abstract
Abstract Continental glaciations during the Pleistocene Epoch created complex systems of aquifers and aquitards across many northern regions of the Earth. The low hydraulic conductivities of glacial till aquitards suggest that limited recharge will reach the underlying aquifers, potentially preserving old groundwaters. Here, we characterize the recharge history in intertill and buried valley aquifers in Saskatchewan, Canada using 14 C, 3 H, 4 He δ 2 H, δ 18 O, and major ions. Intertill aquifers with depths of <30 m had corrected 14 C ages ranging from 0 to 15.5 ka. These aquifers also contained 3 H and/or elevated NO 3 in some locations, indicating that a component of modern recharge had mixed with older water. A single sample from the Judith River bedrock aquifer in the region had a corrected 14 C age of 10.2 ka and elevated NO 3 . Samples from buried valley aquifers with depths of 89 to 123 m contained older waters with ages >38 ka in some locations, indicating that recharge occurred before the last glacial advance over the region. While measuring tracers that cover a wide range of ages is necessary to understand these flow systems, δ 2 H and δ 18 O were less diagnostic because values of modern winter precipitation overlapped with groundwaters with a wide range of ages. The range of ages present in the intertill aquifers of the region indicates that these systems are currently being recharged, which indicates some development of groundwater resources is possible but also points to a need for groundwater protection measures.
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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 | 0.002 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".