Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
Bibliographic record
Abstract
The Masjeddaghi porphyry Cu-Au deposit is situated in the Alborz-Azarbaijan structural zone of northwest Iran. Chemical compositions of rock-forming (biotite, amphibole) and accessory minerals (magnetite, apatite) in the potassic to propylitic altered diorite porphyry of Masjeddaghi serve as key indicators of magmatic-hydrothermal mineralization. In situ LA-ICP-MS was conducted to analyze trace element contents of selected magnetite-bearing samples, while EMPA analyzed biotite, amphibole, and apatite compositions. The mineral compositions show a parental magma with calc-alkaline features, suggesting a source comprised of both subduction mantle-derived and crust-derived materials, and the Masjeddaghi mineralizing magmas have a relatively elevated ƒO2 and are classified as oxidized I-type magmas. The calculated temperature ranges are constrained by Al-in-amphibole geothermometry, saturation temperature of apatite, and the Ti-in-biotite geothermometer (830°C–877°C) (845°C-918°C) and (723°C–782°C), respectively, whereas the Al-in-amphibole geobarometry exhibits formation pressure (120–186 MPa; relating to depths ranging from 4 to 10 km) and H2Omelt content at time of crystallization (4.10–4.46 wt%), indicating formation of a hydrous calc-alkaline magma from a deep magmatic reservoir. The intrusion of oxidized hydrous mafic magma from a deeper magma source likely promoted wide magma mixing and prolonged fractional crystallization within the evolved dioritic magma chamber, resulting in exsolution of the ore-forming fluids and the formation of the Masjeddaghi 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 | 0.001 |
| 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".