A SUPPLEMENTAL PRECAMBRIAN-CAMBRIAN BOUNDARY GLOBAL STRATOTYPE SECTION IN SW CHINA
Bibliographic record
Abstract
Since 1992, the siliciclastic Fortune Head section(southeastern Newfoundland, Canada) and the base of the Trichophycus pedium trace fossil zone have together served as the Precambrian Cambrian(PreC C) boundary global stratotype section and point(GSSP). However, the fact that the Fortune Head section consists mainly of siliciclastic rocks makes it difficult to correlate this section with boundary sections consisting mainly of carbonate rocks, which contain abundant small shelly fossils(SSFs) and can also be correlated using stable carbon isotope data. We propose that a predominantly carbonate section near the town of Dahai, eastern Yunnan Province, southwestern China, be designated a supplementary stratotype for the PreC C boundary GSSP, for the following reasons:(1) the Dahai section is continuous, consisting of the Neoproterozoic Baiyanshao and Daibu members conformably overlain by the Early Cambrian Zhongyicun and Dahai members and Shiyantou Formation; (2) the Early Cambrian units contain abundant SSFs representing four assemblage zones; (3) the Dahai section can be correlated with numerous other sections using stable C isotopic chemostratigraphy; (4) the famous Meishucun section, located not far from Dahai, contains both abundant SSFs and trace fossils and can be readily correlated with the SSF rich Dahai section. We further propose that the base of the Cambrian System be placed at the base of the first SSF assemblage zone(the Anabarites Protohertzina Zone), which in the Dahai section coincides with the base of Bed 11.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".