Provenance of the Early Triassic in the southwestern Sichuan Basin, Upper Yangtze, and its implications for tectonic evolution
Bibliographic record
Abstract
The opening and closure of the Paleo-Tethys Ocean and the tectonomagmatic thermal event in the Emeishan Large Igneous Province (ELIP) along the western margin of the Yangtze Block during the late Paleozoic to early Mesozoic shaped the unique pattern of the basin–mountain system. To put constraints on the provenance and tectonic settings of the Early Triassic deposition in southwestern Sichuan, the detrital compositions and major and trace elements of clastic rocks from the E’mei and Meigu sections were analyzed. The detrital components of sandstones in southwestern Sichuan are related to basaltic, short-transport, recycled clastics. Detrital zircons from the bottom of the Feixianguan Formation in the Meigu section yield U–Pb ages ranging from 246 to 280 Ma, with a major peak at ∼258 Ma, which are consistent with those of published data from the ELIP major magmatic event. The geochemical characteristics of sandstone are similar to the high-Ti Emeishan basalt of the ELIP and Precambrian to Permian sedimentary rocks of the Yangtze Craton. These results, combined with the research findings based on paleogeography data, indicate that the Early Triassic strata in the E’mei–Meigu region probably originated from both the ELIP and Khamdian Paleoland of the inner Yangtze Craton. The formation of the Sichuan Basin was mainly controlled by the Khamdian Paleoland during that time.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| 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".