Geological and geochemical characteristics of the Waconichi Formation east of the Lemoine auriferous volcanogenic massive sulphide deposit, Abitibi greenstone belt, Quebec
Bibliographic record
Abstract
The Lemoine Mine exploited a small but exceptionally rich auriferous volcanogenic massive sulphide body (0.76 Mt of ore grading 4.6 g/t Au). The deposit was located in the Lower Lemoine Member of the Waconichi Formation, in the Chibougamau area of the Archean Abitibi greenstone belt. The Lower Lemoine Member, which is mostly of tholeiitic magmatic affinity, is overlain by the Upper Lemoine Member comprising transitional basalt and transitional to calc-alkaline rhyolite. Field mapping, geochemical analyses, and detailed core logging of every accessible drillhole in the study area, east of the former mine, has helped to define the Lower Lemoine Member subunits and identify their mode of emplacement. The Lower Lemoine Member is composed of multiple extrusive subunits: from the bottom of the volcanic stratigraphy, the Alpha Rhyolite followed by the Lemoine Rhyolite, the Lemoine Dacite, the Lemoine Andesite, and the Hanging-wall Quartz and Feldspar Porphyry. A second, later, component of the Alpha Rhyolite intrudes the Lemoine Rhyolite locally. The Marelle Quartz and Feldspar Porphyry and the Coco Lake Rhyolite represent subvolcanic intrusions that form concordant sills at multiple stratigraphic levels in the Lower Lemoine Member. Preliminary results also indicate the potential presence and general location of previously unrecognized volcanic vents northeast of the Lemoine deposit, which may have been the site of paleohydrothermal fluid up-flow and may host additional mineralization. The precise location of the volcanic vents is the topic of ongoing work and will have implications for exploration for volcanogenic massive sulphides in the area and in similar settings elsewhere. Moreover, our work indicates that the Lemoine auriferous volcanogenic massive sulphide deposit is hosted in a felsic-dominated volcanic sequence comprising a significant portion of shallow intrusive rocks, defining a major thermal corridor over a large synvolcanic intrusion; conditions that may have contributed in forming such a base- and precious-metal-rich deposit.
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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 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".