Negative Carbon Isotope Excursion in the Base Cambrian of Guizhou Province,China: Implication for Biological and Stratigraphical Significance
Bibliographic record
Abstract
The black shale is widely and mostly in the base Cambrian of Guizhou Province. Therefore, to study the carbon isotope excursions on Neoproterozoic—Cambrian boundary in Guizhou Province for geologist is difficult. Then, the 60 m thick base Cambrian consisting of mudstone interbedded thin limestone was discovered recently in Yingping, Fuquan County, Guizhou Province. This discovery is beneficial to study the ocean environment of the early Cambrian. The notable negative C isotope excursion on Neoproterozoic—Cambrian boundary in Yingping, Fuquan County, Guizhou Province compares with the most continuous C isotope chemostratigraphy from the Xiaowaitoushan Member of the Laolin section in Lunaqian village, Huize County, northern Yunnan Province, southwest China, and that from the upper Tsagaan Oloom Formation of southwest Mongolia, and that from the upper Salarrny Gol of northern Siberia, and that from Mackenzie Mt. Canada, and that from Iran, Oman, Poland and Britain. The notable negative carbon isotope excursion has been shown to be a powerful tool for the global division and correlation of Neoproterozoic—Cambrian boundary. The notable negative C isotope excursion in Yingping section, Fuquan County, Guizhou Province, which is located at 20 m thick succession over the Dengying dolostone, then, between this notable negative C isotope excursion and the Dengying dolostone has 8 m thick black shale and siliceous rocks bearing abundant Bradorida and Priapulida fossils, it is shown that ocean animals ware thriving while the black shale and siliceous rocks deposited, but the grey-green mudstone interbedded thin limestone with notable negative C isotope upon the black shale and siliceous rocks is deficient in fossils, and it is shown that mass extinct event at the Neoproterozoic—Cambrian closely relate to this global negative C isotope excursion, but not oxygen-deficient event.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".