An abrupt extinction in the Middle Permian (Capitanian) of the Boreal Realm (Spitsbergen) and its link to anoxia and acidification
Why this work is in the frame
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Bibliographic record
Abstract
The controversial Capitanian (Middle Permian, 262 Ma) extinction event is only known from equatorial latitudes, and consequently its global extent is poorly resolved. We demonstrate that there were two, severe extinctions amongst brachiopods in northern Boreal latitudes (Spitsbergen) in the Middle to Late Permian, separated by a recovery phase. New age dating of the Spitsbergen strata (belonging to the Kapp Starostin Formation), using strontium isotopes and δ13C trends and comparison with better-dated sections in Greenland, suggests that the first crisis occurred in the Capitanian. This age assignment indicates that this Middle Permian extinction is manifested at higher latitudes. Redox proxies (pyrite framboids and trace metals) show that the Boreal crisis coincided with an intensification of oxygen depletion, implicating anoxia in the extinction scenario. The widespread and near-total loss of carbonates across the Boreal Realm also suggests a role for acidification in the crisis. The recovery interval saw the appearance of new brachiopod and bivalve taxa alongside survivors, and an increased mollusk dominance, resulting in an assemblage reminiscent of younger Mesozoic assemblages. The subsequent end-Permian mass extinction terminated this Late Permian radiation.
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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 it