Strong lateral heterogeneities of upper mantle shear-wave structures beneath the central and eastern Tien Shan

The Tien Shan is one of the most active intracontinental orogenic belts worldwide and shows intensive seismicity and tectonic activity that reflects laterally heterogeneous structures. Here, we employ multimode surface wave tomography to construct an anisotropic 3-D shear-wave velocity model, which...

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Bibliographic Details
Published in:International journal of earth sciences : Geologische Rundschau 2022-11, Vol.111 (8), p.2555-2569
Main Authors: Tang, Qingya, Sun, Weijia, Ao, Songjian, Fu, Li-Yun, Xiao, Wenjiao
Format: Article
Language:English
Subjects:
Anomalies
Earth and Environmental Science
Earth Sciences
Geochemistry
Geology
Geophysics/Geodesy
Lithosphere
Mantle plumes
Mineral Resources
Ocean circulation
Original Paper
Orogeny
Sedimentology
Seismicity
SH waves
Shear
Shells
Structural Geology
Subduction
Subduction (geology)
Surface water waves
Surface waves
Tectonics
Three dimensional models
Tomography
Uplift
Upper mantle
Upwelling
Velocity
Wave velocity
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Summary:The Tien Shan is one of the most active intracontinental orogenic belts worldwide and shows intensive seismicity and tectonic activity that reflects laterally heterogeneous structures. Here, we employ multimode surface wave tomography to construct an anisotropic 3-D shear-wave velocity model, which achieves a resolution of 2.0°. The new tomographic model reveals pronounced velocity contrasts between the central Tien Shan, which shows low velocity, and the eastern Tien Shan, which shows high velocity in the depth range of 50–300 km. We interpret that this velocity contrast as potentially resulting from the difference in the uplift mechanism of the Tien Shan. A comprehensive analysis suggested that the uplift of the central Tien Shan might be related to northward subduction of the Tarim lithosphere while the low-velocity anomaly beneath the central Tien Shan might be related to subsequent mantle upwelling. In contrast, the Tarim block in the south collided with the Junggar Basin in the north, which may have led to the uplift of the eastern Tien Shan. The Tarim Basin is mainly characterized by high-velocity anomalies of SV waves but low-velocity anomalies of SH waves beneath the western Tarim Basin, which may be related to the Tarim mantle plume.
ISSN:1437-3254
1437-3262
DOI:10.1007/s00531-021-02149-y