Crustal and Upper Mantle Structure of the Tien Shan Orogenic Belt From Full‐Wave Ambient Noise Tomography

Researchers have uncovered significant variations in the crustal and upper mantle structure of the Tien Shan orogenic belt, shedding light on its lithosphere formation and modification. Using full-wave ambient noise tomography, they extracted high-quality empirical Green's functions from seismic data collected between 2012 and 2014. The study revealed very slow upper crust beneath the Tarim and Junggar sedimentary basins, with strong seismic heterogeneities in the interior of the Tarim Basin. Notably, the high-velocity mantle lithosphere of the Tarim Basin underthrusts northward toward the central Tien Shan, potentially triggering intrusion of hot mantle material and partial melting. In contrast, a connected high-velocity upper mantle structure from the Tarim Basin across eastern Tien Shan to Junggar Basin suggests convergent effects between these basins, preventing asthenosphere upwelling. Low-velocity anomalies in the western Tien Shan indicate subducted continental crust of the Eurasia lithosphere. These findings suggest distinct tectonic mechanisms along the three segments of the orogenic belt.

Lü, Z., Gao, H., Lei, J., Yang, X., Rathnayaka, S., & Li, C. (2019). Crustal and Upper Mantle Structure of the Tien Shan Orogenic Belt From Full‐Wave Ambient Noise Tomography. Journal of Geophysical Research: Solid Earth, 124(4), 3987–4000. Portico. https://doi.org/10.1029/2019jb017387