Rhenium-osmium geochronology of gersdorffite and skutterudite-pararammelsbergite links nickel–cobalt mineralization to the opening of the incipient Meliata Ocean (Western Carpathians, Slovakia)
Bibliographic record
Abstract
Abstract The multi-orogenic crustal segment of the Central Western Carpathians comprises a Variscan basement that is host to small nickel–cobalt (Ni–Co) arsenide and sulfarsenide mineralizations at Ľubietová-Kolba and Čierna Lehota (Slovakia). Here, we constrain the timing of Ni–Co mineralization by using rhenium-osmium (Re–Os) isotope geochemistry of (1) gersdorffite (NiAsS) after krutovite (NiAs2) at Ľubietová-Kolba, and (2) a mixture of skutterudite-pararammelsbergite (CoAs3–NiAs2) from the Čierna Lehota deposit, hosted by metamorphosed carbonaceous rocks. Gersdorffite, which is bereft of common Os, returns a Re–Os model age of 238.2 ± 1.0 (2σ) million years (Ma). Four aliquots of the skutterudite-pararammelsbergite mixture define a robust model 1 isochron at 238.2 ± 12.7 (2σ) Ma (mean square weighted deviates – MSDW = 0.95). A crustal source of Os, and by inference other metals, is inferred from the initial 187Os/188Os ratio of 0.90 ± 0.01 of this isochron. We conclude that studied Ni–Co mineralizations are related to an extensional tectonic regime and hydrothermal fluid flow in connection with the opening of the Meliata ocean in the Middle Triassic (Ladinian).
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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 | 0.001 | 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".