Quantifying the volcanic emissions which triggered Oceanic Anoxic Event 1a and their effect on ocean acidification
Bibliographic record
Abstract
Abstract The Cretaceous Oceanic Anoxic Event 1a (Early Aptian) is thought to be causally related to the eruption of the Ontong Java Plateau large igneous province. This study uses osmium isotope records to quantify the magnitude of the respective CO 2 emissions up to the onset of Oceanic Anoxic Event 1a, and model the associated changes in carbonate saturation state (Ω), atmospheric pCO 2 , carbon isotope ratios and the carbonate compensation depth with a carbon cycle model. These model results suggest that volcanism associated with the rapid negative 187/188 osmium ratios observed during the onset of Oceanic Anoxic Event 1a (Selli Event) increased the planetary CO 2 degassing flux at least six‐fold, causing a negative δ 13 C excursion of ca 1·5‰ in the dissolved surface ocean inorganic carbon pool. This is consistent with previously published δ 13 C data. Volcanic degassing of this magnitude would also suppress the aragonite saturation state of surface water to near under‐saturated values (Ω ca 1·1 to 0·9), shoal the carbonate compensation depth by 1500 m and increase the atmospheric pCO 2 by 3000 p.p.m., before increased weathering and anoxia would counter the pCO 2 increase.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".