Geology and geochemistry of pillow basalt in the Huilvshan region (west Junggar, China): implications for magma source and tectonic setting
Bibliographic record
Abstract
Geological characteristics and geochemical analyses are reported for the early Carboniferous pillow basalt in the Huilvshan region (west Junggar, Northwest China), with the aim to indicate its petrogenesis, magma source characteristics, and tectonic implication. This pillow basalt consists of clinopyroxene and plagioclase with trace amounts of magnetite, apatite, and chromian spinel. It is tholeiitic in composition with low concentrations of Na2O + K2O (1.52–4.74 wt.%). Similar to the N-MORB, the samples of this pillow basalt have nearly flat chondrite-normalized REE patterns ((La/Yb)N = 0.87–1.47) with insignificant Eu anomalies (Eu/Eu* = 0.84–1.18), and show no obvious enrichments of LILEs and insignificant depletions in HFSEs. Petrology and geochemical characteristics suggest that this pillow basalt is the product of MORB-like magma derived from a depleted mantle corresponding to ≤4% partial melting of spinel lherzolite. SIMS analysis of the zircons separated from tuff interlayered with basalt gives a weighted average U–Pb age of 328 ± 3 Ma (MSWD = 1.4), which represents the magma eruption time in the Huilvshan region. From these observations, in combination with the previous work, we conclude that an extensional tectonic regime dominated the tectonic activity of west Junggar during early Carboniferous.
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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 | 0.003 | 0.002 |
| 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) | 0.001 | 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".