Reconstruction of the Yangtze Ramp during Floian to Darriwilian (Ordovician) in South China: Its Morphology, Controlling Factors and Significances
Bibliographic record
Abstract
Abstract A robust stratigraphic framework and a coherent depositional ramp model for the Zitai, Dawan, Meitan and Ningkuo formations of Floian–Darriwilian age (Early–Middle Ordovician) in the Yangtze (Daoba, Xiangshuidong, Daling, Gudongkou and Honghuayuan sections) and Jiangnan regions (Nanba section) was created based on lithofacies and major element analysis. Three siliciclastic (LF1–3) and six carbonate (LF4–9) lithofacies are recognized representing sediments that were deposited in mixed siliciclastic and carbonate ramp environment. The intensity of mixed sedimentation and terrigenous input were evaluated using the elemental proxies Intensity of Mixed sedimentation (IM) and Aluminum Accumulation Rate (AlAR), as well as their mean values during certain time intervals. Mixed sediments are most well‐developed along the marginal Yangtze region, strongly impacted by recurrent influx of westerly derived terrigenous materials in response to global eustatic changes and regional tectonic movements, shaping the gently southeast‐dipping morphology. Regular terrigenous influx resulted in periods of enhanced primary productivity on the Yangtze Ramp as evidenced by matching biodiversity peaks in planktonic organisms, i.e., chitinozoans and acritarchs. Brachiopods and other shelly fauna were also able to proliferate as new niches developed along the gently dipping ramp floor with substrate changes. The biodiversification patterns suggest that terrigenous influx controlled in part by regional tectonics played a more important role than previously thought in the development of Great Ordovician Biodiversification Event in South China.
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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 | 0.003 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".