Late-alpine five-element mineralization in the Punta Corna vein system (Western Alps): evolution of methane-bearing crustal fluids and their role to arsenide precipitation and ore-deposit metallogeny
Bibliographic record
Abstract
The Punta Corna vein system (PC), located within the Western Alpine meta -ophiolites, is characterized by a five-element vein type mineralization including Fe-Co-Ni arsenides preceded and followed by a typical base-metal sulfide mineralization, comprising tetrahedrite, chalcopyrite, pyrite and galena. Three distinct hydrothermal stages were recognized: Sulfide stage I, Arsenide stage and Sulfide stage II. Microthermometric analysis of fluid inclusion assemblages from Sulfide stage I allowed to constrain fluid A (surface-derived, sulfate-bearing, ∼27.3 wt% total salinity and 140 °C homogenization temperature) and fluid B (deep-seated, methane-bearing, 18.8 wt% total average salinity and 163 °C homogenization temperature). The Arsenide stage is characterized by the presence of fluid C (deep-seated, ∼19 wt% total average salinity and 156 °C homogenization temperature) and fluid D (deep-seated, ∼13 wt% total average salinity and 230 °C homogenization temperature). Fluids B and C are inferred to represent the same fluid, with and without methane, respectively. The absence of methane in fluid C is interpreted as its consumption during arsenide formation by reduction. This detailed fluid inclusion study revealed evidence of pre-ore methane, which has been proposed as a reducing agent, important in the formation of five-element mineralization. This finding has two important implications: (i) it constrains the shift from a hydrothermal system precipitating base metal sulfides to a five-element one through the mixing of a metal-bearing fluid and a highly reduced methane-bearing fluid, and (ii) it records the presence of an oxidized sulfate-bearing brine and the reduced-metal bearing fluid in the crustal rocks, which mixed and thus formed the five-element mineralization. Crucial to this process is the role of late-Alpine brittle tectonics, which, through the development of two main fault systems, enhanced rock permeability allowing the input of different fluids in the active hydrothermal system.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 teacher head, 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".