Discovery and significance of Cu–Zn intermetallic compounds in the Jingxi gold deposit, western Tianshan Mountains, NW China
Bibliographic record
Abstract
A group of Cu–Zn intermetallic compounds has been discovered in breccias at the Jingxi gold deposit, NW China. The host rocks, silicified tuff and andesite, are cut by pyrite‐bearing quartz veins and are intensely silicified which leads to a high SiO2content (over 85%). The main component of breccia is siliceous rock, with the cement mainly siliceous and tuffaceous. Under the reflected light microscope, the Cu–Zn intermetallic compounds have quadrilateral shapes which range in size from 6 to 28 µm. Scratches and pitting can be seen on the surfaces of them. The reflection colour of these intermetallic compounds is golden yellow, similar to gold but slightly more white, with a reflectivity that is lower than that of Au and is more close to that of pyrite. They are weakly bireflectant, ranging from bright yellow to golden yellow. Under polarized reflected light, they show a weak anisotropism and no internal reflections. The EMPA (WDS) results of the intermetallic compounds reveal that the ranges of concentration (wt%) are Cu: 81.35 ~ 85.36 (on average 83.75), Zn: 6.08 ~ 10.10 (on average 7.39), Sn: 4.13 ~ 6.75 (on average 5.23) and Ni: 0.88 ~ 1.38 (on average 1.05), with minor S: b.d. ~ 5.05. Compared with other Zn–Cu intermetallic compounds previously described, these Cu–Zn intermetallic compounds can be classified as α portion phase which has an over 80% Cu content. In the Jingxi gold deposit, the Cu–Zn intermetallic compounds occur as xenomorphic grains and are paragenetically closely linked with the formation of planar silicification. The characteristics of ore type, ore mineral assemblages and ore textural relations demonstrate that these Cu–Zn intermetallic compounds were formed during the early stage of mineralization (I stage) under conditions of both lowfO2andfS2. Generally speaking, the native elements and their intermetallic compounds formed at the high melting temperatures under strongly reducing conditions, with O and S absent. Because of the sudden drop of the confining pressure, we believe that fast upwelling and cooling of magmatic hydrothermal fluid make reactions between S and Cu/Zn difficult when S is either absent or present. As a result, Cu–Zn intermetallic minerals will deposit. Copyright © 2014 John Wiley & Sons, Ltd.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".