Geochronology, geochemistry, and Hf isotope of quartz monzonite and diorite in dachaigou, the East Kunlun orogenic belt, China, and their geological significance
Bibliographic record
Abstract
This study focuses on quartz monzonite and diorite plutons in Dachaigou, East Kunlun, examining their formation, age, petrogenesis, magmatic source, and tectonic setting. Through comprehensive field observations, zircon geochronology, geochemistry, and Hf isotope analysis, new insights into the Paleozoic tectonic evolution of the proto-Tethys Ocean in the East Kunlun orogenic belt are provided. Zircon U–Pb dating reveals that quartz monzonite and diorite formed at 417.4 ± 2.1 and 404.6 ± 1.8 Ma, respectively. Geochemical analysis shows that the A/CNK value of quartz monzonite ranges from 0.98 to 1.07, with the Pb content proportional to SiO2, which aligns with the characteristics of I-type granite. The εHf(t) values for quartz monzonite and diorite are −0.84 to 2.2 and −13.22 to 2.04, respectively. Considering the formation age, geochemical characteristics, and regional tectonic evolution, it is concluded that quartz monzonite has a crust-derived origin, whereas diorite has a crust–mantle mixing origin. Both were formed in a post-collision extensional tectonic setting resulting from slab break-off, implying the Proto-Tethys Ocean East Kunlun entered a post-collisional extension stage in the Late Silurian–Early Devonian.
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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".