Laser ablation ICP-MS study of trace elements in scheelite in different types of mineralization from the Bohemian Massif
Bibliographic record
Abstract
We describe scheelite in five types of mineral deposit from the Bohemian Massif (greisen, orogenic Au, reduced intrusion-related gold systems (RIRGS), oxidized and reduced skarn) via cathodoluminescence (CL) imaging and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses. We document variability in the scheelite composition within single grains and/or deposit types that reflects the nature and evolution of the ore-forming fluids. We provide scheelite typical trace element characteristics and chondrite-normalized REE patterns for different deposit types, confirming that scheelite can be used as an indicator mineral for their exploration. For example, scheelite from greisen-related deposits is usually rich in Sn, Sr, Y and HREE with various ranges of median values in individual deposits (0.05–8.0 ppm, 232.4–567.1 ppm, 0.06–465.0 ppm and 0.06–632.5 ppm, respectively) and with typical chondrite-normalized REE patterns showing Eu negative or positive anomaly. Under UV light scheelite from Sn-W deposits displays variable colours from whitish via yellowish to bluish. In contrast to greisen-related deposits, scheelite from Au-orogenic association is usually relative rich in Pb (median range in individual deposits: 6.1–11.2 ppm), and relatively poor in Mg, Mo and Nb. Flat and bell-type chondrite-normalized REE patterns show a pronounced Eu positive anomaly. Under UV light it is predominantly homogenous and bluish. Scheelite from oxidized skarn is enriched in Mo, Nb and ΣLREE (median range in individual deposits: 311.4–7214.1 ppm, 1.3–214.9 ppm, and 1.1–1375.8 ppm, respectively), and scheelite from reduced skarns is characterized by the lowest median ranges of Nb (1.7–107.8 ppm), Y (0.69–41.1 ppm), Mn (0.5–17.0 ppm) and Zn (0.04–0.252 ppm) in individual deposits, when compared to all the groups studied. Scheelite from oxidized and reduced skarn deposits displays several types of chondrite-normalized pattern: (1) LREE-enriched with a positive or negative Eu anomaly, (2) Bell-shaped REE patterns with negative or without Eu anomaly, and (3) Flat REE patterns with a negative Eu anomaly. Scheelite from oxidized and reduced skarn deposits is commonly zoned and mostly bluish under UV light.
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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 | 0.000 |
| 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 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".