Sedimentary characteristics and detrital zircon <scp>U–Pb</scp> isotopes of the Upper Permian–Lower Triassic strata in eastern Ordos Basin, Central North China
Bibliographic record
Abstract
A series of tectonic activities induced by the subduction of the Palaeo‐Asian Ocean (PAO) in the Palaeozoic have been recorded in the North China Craton (NCC). Sedimentary strata provide some precious records to reconstruct the basin evolution in the NCC. In this study, we carried out detrital zircon LA‐ICP‐MS U–Pb dating, sandstone modal analysis, bulk‐rock major, and trace elemental measurements for the Sunjiagou and Liujiagou formations in the eastern Ordos Basin to trace the material source. The results show that the sedimentary rocks were mostly sourced from active continental margins. The detrital zircon ages of the Sunjiagou and Liujiagou formations spread from >3,000 to 250 Ma with peaks of main age populations at 2,508, 1,890, 430, and 270 Ma. Based on the age comparison and the southward palaeocurrents, we consider that the source material of these sedimentary rocks comes from the northern margin of the NCC. This in turn indicates that the amalgamation of the PAO and the NCC should have finished at least by the end of the Late Permian.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".