Redox, pH and SP variation over mineralization in thick glacial overburden. Part I: methodologies and field investigation atthe Marsh Zone gold property <sup>*</sup>
Bibliographic record
Abstract
A surface and subsurface investigation of pH, oxidation–reduction potential (ORP) and spontaneous potential (SP) was carried out over sulphide-hosted gold mineralization in an area of thick and extensive glacially derived overburden. Protocols were developed to measure ORP and pH in clay slurries, peat and groundwater to test for the presence of redox and pH phenomena that were predicted to occur over mineralization. ORP protocols focused on removing memory effects caused by probe history and storage and on obtaining a reproducible measure of the ORP over mineralization relative to background areas. The results confirm the presence of distinct reduced ‘columns’ in clay and interstitial groundwater overlying sulphide mineralization that are in fact reduced ‘curtains’ that follow the trace of mineralization. These are accompanied by high pH within the reduced column, with minor lows on the flanks, and elevated H 2 S and CO 2 in shallow groundwater over mineralization. Whereas the H 2 S appears to have its source in bedrock mineralization, the CO 2 is likely a secondary near-surface phenomenon related to oxidation of metals in the reduced column, which produces acid and concomitant dissolution of carbonate in the clays. Wide groundwater temperature anomalies are spatially associated with mineralization. High ORP in shallow peat above mineralization may be evidence of an ‘oxidized cap’ over the reduced column. A minor SP response in surface peat was noted but is small in comparison to the redox field voltage . The presence of reduced columns and other features are consistent with a previously published redox-gradient transport model.
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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 | 0.000 |
| 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".