Magnetotelluric Evidence for Asymmetric Simple Shear Extension and Lithospheric Thinning in South China
Bibliographic record
Abstract
Abstract Extension and rifting of the lithosphere is fundamental to the evolution of the continents, but the mechanism by which the lithosphere thins under extension remains enigmatic. Using a new dense array of magnetotelluric data from the rifted margin of southeast China, we resolve the three‐dimensional electrical resistivity structure of the lithosphere to constrain the process of rifting and thinning. Our results reveal a brittle‐ductile transition zone in the Cathaysia Block, featuring low electrical resistivity and low seismic velocity at 15‐ to 20‐km depth. A southeast directed dip is resolved for the Jiangshan‐Shaoxing Fault—a suture zone originally formed by the Neoproterozoic collision of Yangtze and Cathaysia Blocks. This boundary fault had been reactivated to different extents by the Early Paleozoic and Early Mesozoic intracontinental orogenies of south China. Its present structural style, however, was interpreted as a lithospheric‐scale detachment fault that acted during the Late Mesozoic extension and rifting. Given the asymmetries of topography, electrical resistivity, Bouguer gravity anomaly, and Late Mesozoic volcanism across the Gan‐Hang Rift, we propose an asymmetric simple shear extension model for the south China rift system. Water content of up to 0.1 wt% and melt fraction of up to 1% are estimated at 70‐km depth beneath the central Wuyi Mountains, suggesting hydration and partial melting of the mantle lithosphere. The hydration weakening of the mantle lithosphere promoted both the gravitational instability and convective removal of the lowermost lithosphere in south China.
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 | 0.001 | 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) | 0.001 | 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".