Facies architecture of a subaqueous volcano–sedimentary succession on Bogda Mountains, NW China—Evidence of extension in Late Carboniferous
Bibliographic record
Abstract
A Late Carboniferous volcano–sedimentary complex outcrops on the southwestern flank of the Bogda Mountains, NW China. The volcanic architecture, spatial relationships, and emplacement mechanisms of the lithofacies were studied in detail, providing a lithofacies context for previously published structural and geochemical studies and constraining the reconstruction of palaeo‐environments. Four distinct volcano–sedimentary facies are identified in the Qijiagou Formation: close‐packed pillow basalts, pillow basalts with interstitial sediments, hyaloclastites, and peperites. Textural features of the lithofacies, especially hyaloclastites and peperites, provide clear evidence for in situ fragmentation of lava flows, co‐volcanic sedimentation of limestone, and intimate interaction between lava, water, and sediments. They demonstrate autochthonous, subaqueous origin of the succession. Discovery of peperites and stratigraphic transitions of the related lithofacies indicate a progressively deepening subaqueous environment, resembling a volcanic evolution from early stage of eruption at a shallower level to increasingly subsiding basin with increasing eruption frequency of basaltic lava at greater water depth. Vesicularity of basalts, ambient pressure, and peperitic features indicate eruption depth at between 1,500 and 2,500 m. The deep extensional basin in the Baiyanggou area was coeval with bimodal volcanism, uplift, and granite intrusion along strike in the region, all indicating continental collision and post‐collisional extension. The substantial depth of the Baiyanggou Basin indicates that it may have been a back‐arc or even a residual oceanic basin.
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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 | 0.001 |
| 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) | 0.000 | 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".