Mercury evidence of Emeishan volcanism driving the mid-Capitanian (Middle Permian) extinction
Bibliographic record
Abstract
Abstract The mid-Capitanian (Middle Permian) extinction has been widely attributed to the eruption of the Emeishan large igneous province. Here, we investigate the nature and timing of this link by determining Hg concentrations and isotopic compositions of limestones from the Xiongjiachang section of southwestern China, where Emeishan basalts directly overlie sediments recording the mid-Capitanian extinction horizon. Results show an initial Hg-enrichment interval ~2.2 m below the mid-Capitanian extinction horizon. Positive Δ199Hg values in the Hg-enrichment interval suggest enhanced volcanic Hg influx into the ocean via atmospheric Hg(II) deposition. The late stage of the mid-Capitanian extinction interval has lower Δ199Hg values, which indicates enhanced input of terrestrial Hg due to ecosystem collapse and soil erosion. The results of this study provide evidence that the Emeishan large igneous province eruption occurred earlier than the mid-Capitanian extinction, and establish a more reasonable temporal link between Emeishan large igneous province volcanism and the mid-Capitanian extinction.
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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".