Timing of Orogenic Exhumation Processes of the Qinling Orogen: Evidence From<sup>40</sup>Ar/<sup>39</sup>Ar Dating
Bibliographic record
Abstract
Abstract The Qinling Orogenic Belt was formed by long‐lived subduction and collision between the North and South China blocks. Our 40 Ar/ 39 Ar geochronological data of amphibole, white mica, and biotite reveal different exhumation and cooling histories of the major units in the North Qinling Belt and South Qinling Belt (SQB), constraining the multiple orogenic processes. The exhumation of the Qinling Group in the North Qinling Belt started before 432 Ma, through about 500 °C during 432.3–405 Ma, followed by rapid cooling below 425 °C at 388.9 ± 1.1 Ma and slow cooling through about 300 °C during 333.3–329.5 Ma. A similar exhumation history of the Kuanping Group started from about 383 Ma, cooled below 425 °C at 364.9 ± 1.2 Ma and 300 °C at 341.8 ± 1.3 Ma. The metamorphic fore‐arc sedimentary wedge cooled below 500 °C during 322–311.2 Ma, below 425 °C at 306.3 ± 2.8 Ma, and 300 °C at 249 ± 2.8 Ma. However, the white mica 40 Ar/ 39 Ar ages of 349.4 ± 5.1 and 363.2 ± 2.5 Ma constrain the syntectonic metamorphic crystallization age of the Devonian Liuling Group in the northern SQB, whereas 228.2 ± 0.7 Ma indicates either a delayed cooling of the Wudang Group in the southern SQB or a second stage of low‐temperature thermal overprint. Together with previous cooling ages and regional geology, our new data support a tectonic model of Early Paleozoic Andean‐type orogeny with subsequent Late Paleozoic continental subduction in the Qinling Orogenic Belt.
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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".