Dating Subhorizontal Ductile Fabric in the Feidong Complex via Zircon and Titanite U–Pb Geochronology: Insights into Middle Triassic Transpressional Deformation along the Southern Tan-Lu Fault Zone
Bibliographic record
Abstract
Abstract The Triassic collision between the Yangtze and North China blocks resulted in the formation of ultrahigh-pressure metamorphic rocks along the Dabie-Sulu orogenic belt, the development of the Tan-Lu fault zone, and the establishment of a crustal-scale décollement within the Lower Yangtze foreland fold-thrust zone. The ductile fabrics exposed in the Zhangbaling–Feidong Complex of the southern Tan-Lu fault zone record the strain that accumulated during that collision. Herein, field observations and structural analysis of high-strain rocks (i.e. microstructures and quartz crystallographic preferred orientations) from the eastern Feidong Complex are combined with estimates of deformation P-T conditions to reveal that top-to-SSW subhorizontal, amphibolite-facies (600 and 700℃, 4.0–6.6 Kbar) ductile fabrics overprint the Paleo-Proterozoic Feidong Complex. U–Pb geochronology on zircon rims and syntectonic titanite indicates that the overprinting deformation occurred in the Middle Triassic (ca. 246–242 Ma). Reinterpretation of reflection seismic profiles across the Tan-Lu fault zone and Lower Yangtze foreland fold-and-thrust zone identifies a large, subhorizontal décollement beneath the sedimentary cover that appears to have influenced the formation of fold-thrust structures in the Lower Yangtze foreland. These new observations and geochronological results are consistent with a transpressional tectonic model wherein the Early-Middle Triassic northward indentation of the Yangtze block into the North China block drove deformation within the southern Tan-Lu fault zone.
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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| 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".