Carbon isotope perturbations are not primarily driven by volcanism during the Late Paleozoic Ice Age
Bibliographic record
Abstract
Abstract The late Paleozoic ice age (LPIA) was the longest-lived glaciation of the Phanerozoic, and its demise marks Earth’s only recorded transition from an icehouse to a greenhouse state since the occurrence of vascular plants and complex terrestrial ecosystem. While global volcanism has been widely considered a key driver of carbon cycle during this period, limited high-resolution records have constrained our understanding. Here, we use high-resolution carbon isotope and mercury records from the North China Craton, spanning the late Gzhelian to early Kungurian stages, to evaluate the relationship between carbon cycle perturbation and volcanism. We identify two negative carbon isotope excursions during the late Gzhelian and early Asselian, both coinciding with climate warming. Our data reveal a variable relationship between carbon cycle disturbances and mercury records, suggesting volcanism was not the only trigger. Instead, they may result from the superimposition of multiple mechanisms, including tundra conditions, methane release, or orbitally-paced climate changes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".