Infaunal response during the end-Permian mass extinction
Bibliographic record
Abstract
Abstract The end-Permian mass extinction (EPME) profoundly shaped shallow marine ecosystems. Although much has been learned about this event based on the body-fossil record, the global infaunal response to the EPME, as represented by ichnofossils, is much less understood. Here we analyze secular changes in ichnodiversity and ichnodisparity from the late Permian to the Middle Triassic based on a global trace-fossil data set. Results show that, in contrast to the body-fossil record, late Permian global ichnodiversity and ichnodisparity maintained their level until the Griesbachian, followed by a sharp loss in the Dienerian. Notably, the Griesbachian shows an unusual dominance of shallower tiers. The discrepancy between the body- and trace-fossil record is interpreted to be the result of the resurgence of widespread microbial matgrounds in the Griesbachian that aided the preservation of surface, semi-infaunal, and shallow-tier ichnofossils. Our study shows that the EPME strongly affected the sediment mixed layer, allowing the preservation of shallower tier trace fossils. The disappearance of the mixed layer in the earliest Triassic may have enhanced pyrite burial in sediments and inhibited its further re-oxidation, therefore impacting sea water sulfate concentrations.
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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 | 0.000 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".