Trace elements in ore minerals as indicators of hydrothermal fluid evolution in the Au-rich porphyry system of Iron Cap, British Columbia, Canada
Bibliographic record
Abstract
Trace elements in ore minerals are increasingly utilised to illuminate genetic processes, and improve mineral exploration and processing approaches. However, the ore minerals of porphyry deposits have received limited study, despite the need to better understand the nature of hydrothermal fluid evolution in porphyry systems. In this thesis, the trace element contents of the ore mineral assemblages of successive vein generations are examined to investigate variations in hydrothermal fluid characteristics throughout formation of the Au-rich porphyry deposit of Iron Cap, British Columbia, Canada. Detailed petrographic analyses have led to the classification of eight vein generations at Iron Cap. Trace element analyses by LA-ICP-MS reveal that different vein generations exhibit unique geochemical signatures. Both Se and Ag display consistent ore mineral partitioning trends between vein generations, but their concentrations vary systematically. This suggests that these elements record specific changes in hydrothermal fluid characteristics between vein generations, such as temperature, pH, and/or salinity. A lattice strain model for pyrite has been developed, which shows that Co and Ni are lattice-hosted, and actually exhibit higher partition coefficients for pyrite than Fe does. This means that Co/Ni ratios in pyrite (0.2 to 186.6) directly record Co/Ni ratios in the hydrothermal fluids. Fluctuations in Co/Ni ratios in pyrite growth zones revealed by trace element mapping illustrate that the characteristics of the hydrothermal fluids precipitating the pyrite at Iron Cap are regularly oscillating, which can only be explained by the influx of multiple different fluids during vein formation. This research shows that trace elements in porphyry ore minerals have the potential to elucidate genetic processes. In particular, hydrothermal fluid evolution in porphyry systems is shown to be inherently chaotic and complex on both the local and deposit scale, with specific veins necessarily formed by numerous episodes of fluid pulsing, fluid mixing, and/or vein re-opening.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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".