Ash deposits link Oceanic Anoxic Event 2 to High Arctic volcanism
Bibliographic record
Abstract
Abstract Oceanic Anoxic Event 2 (OAE 2) was a major environmental perturbation that occurred ∼94 million years ago. It is associated with profound changes in global climate and carbon cycling, which are commonly attributed to large-scale carbon release from large igneous province (LIP) volcanism. However, the specific LIP(s) involved and the mechanisms of carbon release remain poorly understood, as indicated by discrepancies between carbon release rates suggested by numerical models and LIP degassing estimates. Our study refines the eruptive history of the High Arctic large igneous province (HALIP) by dating ashfall deposits in marine sediments from the Canadian High Arctic using an integrated stratigraphic approach. Our results show that silicic HALIP volcanism began tens of thousands of years before OAE 2, suggesting a strong causal link. Volcanic activity coincides with a marked shift in carbon isotope values, linked to the degassing of HALIP magmas and/or thermogenic gas release. We propose that the concurrent activity of two LIPs—the HALIP and the Kerguelen Plateau—could account for the high rates of carbon release inferred for OAE 2, providing a hypothesis for its pervasive environmental impact.
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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 | 0.001 |
| 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".