Major geological events in the late Guadalupian and carbon–strontium isotope responses in the Yangtze platform, South China
Bibliographic record
Abstract
Two sections of marine carbonate strata, Podu and Lengshuixi, from the Yangtze platform, South China, are investigated in terms of major geological events and carbon–strontium isotope responses. The results show a large-scale regression and a Large Igneous Province (LIP) event occurred in succession in the short interval of the late Guadalupian, inducing a biodiversity crisis. The regression event, marked by an increase in the 87Sr/86Sr ratio, is observed in the Jinogondolella postserrata Zone. It contributed significantly to the reduction in species habitat, leading to notable losses within the shallow-water species assemblage. A subsequent LIP event occurred after the appearance of Jinogondolella altudaensis, releasing CO2 and numerous other deleterious gases that further amplified the crisis in shallow-water to deep-sea environments. The corresponding decline in Sr and C isotopes could have been a response to the basaltic eruption (relative increase from mantle-derived Sr) and release of 12C-enriched CO2. During the process of creation of the LIP, the decline in δ13Ccarb was mainly associated with 12C-enriched CO2 release from organic matter in sedimentary strata, and high-temperature isotope fractionation during the volcanic eruption stage (exceeding 1200 °C). This study could further provide valuable clues regarding the development process of the major geological events and the causes of the biodiversity crisis.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 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".