Academic Journal
Crustal Flow‐Driven Plateau Growth and Expansion Front in NE Tibet: Insights From High‐Resolution Attenuation Tomography With High‐Density ChinArray Lg Data.
| Τίτλος: | Crustal Flow‐Driven Plateau Growth and Expansion Front in NE Tibet: Insights From High‐Resolution Attenuation Tomography With High‐Density ChinArray Lg Data. |
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| Συγγραφείς: | Li, Ruo‐Jie1,2 (AUTHOR), Zhao, Lian‐Feng1,3 (AUTHOR) zhaolf@mail.iggcas.ac.cn, Xie, Xiao‐Bi4 (AUTHOR), He, Xi1 (AUTHOR), Yao, Zhen‐Xing1 (AUTHOR) |
| Πηγή: | Geophysical Research Letters. 1/28/2026, Vol. 53 Issue 2, p1-11. 11p. |
| Θεματικοί όροι: | *Structural geology, *Neotectonics, *Attenuation of seismic waves, *Rock deformation, *Viscosity, *Seismic surveys |
| Γεωγραφικοί όροι: | Tibet (China), Tibetan Plateau |
| Περίληψη: | The Northeastern (NE) Tibet, as the front of plateau growth, widely absorbs northeastward extrusion, leading to significant uplift and forming a basin‐mountain tectonic framework. However, it remains unclear how the crust of NE Tibet deformed in response to the far‐field effects of the India‐Eurasia collision. Here, we construct a high‐resolution broadband crustal QLg model in NE Tibet using seismic attenuation tomography based on high‐density ChinArray Lg data. Strong Lg attenuation was observed beneath the Songpan‐Ganzi, suggesting crustal ductile material flow. The Qilian orogeny, characterized by relatively weak low‐QLg anomalies, may have experienced an early stage of plateau formation. The lateral variation in crustal rheology, as revealed by the Lg attenuation gradient, exhibits a distinct strength contrast between the plateau interior and the forelands, indicating a crustal‐scale boundary of plateau expansion. Cenozoic tectonic extrusion and subsequent ductile material flow jointly govern the crustal deformation of NE Tibet. Plain Language Summary: Dense permanent and multi‐stage mobile networks, including the ChinArray‐Himalaya II, recorded a large amount of high‐quality data, providing an unprecedented opportunity to investigate the crustal attenuation structure beneath northeastern (NE) Tibet. We construct a high‐resolution broadband Lg‐wave attenuation model for this region to constrain crustal rheology, calculate the QLg gradient, and use its steepest segment to distinguish the soft, hot, ductile plateau from the hard, cold, rigid cratonic basins at the crustal scale. From this, we determined the boundary of plateau expansion and gained a better understanding of crustal deformation mechanisms in NE Tibet. The QLg model between 0.3 and 2.0 Hz provides the best characterization for regional geological blocks. Pronounced low‐QLg anomalies, widely distributed in the Songpan‐Ganzi and West Qinling, are inferred to result from crustal ductile material flow on a geological timescale. To the north, in contrast, the isolated low‐QLg zone beneath the Qilian orogen possibly originates from brittle crustal shortening. Our results support the coexistence of ductile crustal flow and brittle deformation, thereby enhancing understanding of tectonic evolution in NE Tibet. Key Points: A high‐resolution broadband crustal Lg‐wave attenuation structure is established in Northeastern (NE) TibetStrong Lg attenuation indicates potential ductile crustal flow beneath the Songpan‐Ganzi block and possible brittle Qilianshan shorteningMultiple crustal deformation mechanisms may jointly control the tectonic evolution of the NE margin of the Tibetan Plateau [ABSTRACT FROM AUTHOR] |
| Βάση Δεδομένων: | Academic Search Index |
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