Abstract Lowermost mantle is a critical region for understanding Earth's deep material circulation and thermal evolution. The Asia‐Pacific region, characterized by a complex history of plate convergence involving the Tethyan, Paleo‐Asian and Paleo‐Pacific domains, serves as an ideal natural laboratory for studying deep mantle processes. However, the fine‐scale shear wave velocity structure of this region remains poorly resolved. In this study, we invert a substantial data set of over 57,000 ScS‐S differential travel‐time residuals to image shear wave velocity perturbations within the D ″ layer beneath the Asia‐Pacific region. We systematically evaluate 16 3‐D global tomographic models, identifying HMSL‐S06 as the optimal lowermost‐mantle model in the Asia‐Pacific region. Extensive high‐velocity anomalies are widespread beneath the continental interior, which may be interpreted as remnants of the subducted Mongol‐Okhotsk, Tethys and Izanagi plates. Another distinct high‐velocity anomaly is newly detected in the southeast of Philippine Sea, representing a poorly constrained remnant of intra‐oceanic subduction within Panthalassa. Segmented low‐velocity anomalies are imaged beneath the South China Sea, being evidence for possible mantle plumes from the core‐mantle boundary. Our study offers a comprehensive map of lower mantle velocity variations beneath the Asia‐Pacific region, yielding specific and valuable constraints for geodynamic modeling and paleo‐plate reconstruction in this complex region.
Ye et al. (Mon,) studied this question.
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