Till, stream sediment, and stream water geochemical signatures of intrusion-hosted Sn-W deposits: examples from the Sisson W-Mo and Mount Pleasant Sn-W-Mo-Bi-In deposits, New Brunswick
Bibliographic record
Abstract
Indicator minerals methods for intrusion-hosted Sn and W deposits were tested at the intrusion-hosted Sisson W-Mo and Mount Pleasant Sn-W-Mo-Bi-In deposits in eastern Canada as part of the Geological Survey of Canada's (GSC) Targeted Geoscience Initiative 4 (TGI 4). The program was a collaborative federal geoscience program with a mandate to provide industry with the next generation of geoscience knowledge and innovative techniques that will result in more effective targeting of buried mineral deposits. The case studies are a collaborative effort between the GSC, the New Brunswick Department of Energy and Mines (NBDEM), and the holders of the Sisson (Northcliff Resources Limited, Hunter Dickinson Inc.) and the Mount Pleasant (Adex Mining Inc.) deposits, and Laurentian University. The detailed till mineralogical + geochemical study described here is one of the first reported for major Sn-W deposits in glaciated terrain. Indicator minerals were examined in heavy mineral (>3.2 specific gravity) concentrates of bedrock and till samples from both deposits, as well as in stream sediment samples from the Sisson deposit area. The <0.063 mm fraction of till samples from both deposits was analysed geochemically using modified aqua regia (partial) and borate fusion (total) digestions. Indicator/pathfinder trace elements in till at the Sisson W-Mo deposit includes W, Mo, Cu, Zn, Pb, Ag, Bi, In, As, Cd, Zn, and Te. Indicator/pathfinder trace elements in till at the Mount Pleasant Sn-W-Mo-Bi-In deposit includes Sn, W, Mo, Bi, In, Ag, As, Cd, Cu, Pb, Re, Te, Tl, and Zn. These element suites reflect the polymetallic nature of these deposits and the broader suite of elements that is now available using modern analytical methods such as inductively coupled plasma - mass spectrometry. The Mount Pleasant deposit is a significant source of indium and till down ice of the deposit contains some of the highest indium values (13 ppm) ever reported for till, indicating that till geochemistry can be an important exploration tool for In-bearing deposits. Indicator/pathfinder elements in stream sediment downstream of the Sisson deposit include W, Mo, Ag, As, Bi, Cd, Cu, In, Tl, and Zn. Indicator/pathfinder elements in stream water around the Sisson deposit include W, Mo, As, Cd, Cu, Cs, and Zn. Indicator minerals of the Sisson deposit identified in the 0.25-0.5 mm fraction of mineralised bedrock, till, and stream sediments include scheelite, wolframite, molybdenite, chalcopyrite, Bi minerals (joseite, native Bi, bismutite, bismuthinite), galena, sphalerite, arsenopyrite, spessartine, pyrrhotite, and pyrite. Indicator minerals of the Mount Pleasant deposit identified in the 0.25-0.5 mm fraction of mineralised bedrock and till include cassiterite, wolframite, molybdenite, topaz, fluorite, galena, sphalerite, chalcopyrite, galena, arsenopyrite, pyrite, and loellingite. Additional but rare secondary indicator minerals of the Mount Pleasant deposit include beudantite, anglesite, and plumbogummite which formed by oxidation and weathering of the galena. The extensive suite of indicator minerals for both deposits reflects their polymetallic natures and the ability of modern indicator mineral methods to recover these minerals. Indicator minerals present in the coarse (0.5-2.0 mm) heavy mineral fraction of till indicate proximity to the mineralised source. A commercial service is now available to systematically determine the scheelite contents of heavy mineral concentrates using its short wave ultraviolet light fluorescence. This service will provide consistent scheelite results within, and between, heavy mineral sampling surveys. Fluorite abundance was shown to be most abundant in the 3.0-3.2 SG (mid-density) fraction of till and can be readily recovered by including a mid-density heavy liquid separation as part of the processing procedures.
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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 | 0.002 |
| 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".