Organic geochemistry and petrology of sedimentary exhalative Pb-Zn and polymetallic hyper-enriched black shale deposits in the Selwyn Basin, Yukon
Bibliographic record
Abstract
Paleozoic strata of the Selwyn Basin host sedimentary exhalative (SEDEX) Pb-Zn deposits, and age-correlative strata of the Richardson trough host polymetallic hyper-enriched black shale (HEBS) deposits. In both deposit types, organic matter is spatially and temporally associated with mineralization. We investigated the characteristics of organic matter in mineralization and unmineralized host rocks in the XY Central SEDEX deposit in the Howard's Pass district, and the Nick and Peel River HEBS deposits in the Richardson trough using Rock-Eval pyrolysis, organic petrography, and solvent extraction and gas chromatography mass spectrometry (GCMS) analysis of the soluble organic matter (SOM). All samples experienced extremely high thermal maturity (Tmax up to 599°C), indicating they contain low SOM. Rock-Eval parameters S1, S2, HI, and OI values are low. Total organic carbon (TOC) values are low for Nick and Peel River and are generally higher for XY Central. Residual carbon values are universally high. Mineral carbon values are low for deposits studied (one outlier). Pyrobitumen reflectance is mostly below 5.80%. Full-scan GCMS analyses of SOM reveal that most, if not all, high molecular weight hydrocarbons, including biomarkers, have been lost due to thermal cracking and many detected peaks are likely due to contaminants introduced during sampling.
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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) | 0.001 | 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".