American Geophysical Union (AGU) Acta Medica Okayama 0094-8276 53 2 2026 Davemaoite Elasticity Reveals Slab]Induced Heterogeneity in the Mantle Transition Zone e2025GL118147 EN Yingxin Yu State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Xinyue Zhang State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Dongzhou Zhang GeoSoilEnviroCARS, University of Chicago Luo Li State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Zhu Mao State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Ningyu Sun State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Denglei Wang State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Jing Li State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Chaoshuai Zhao State Key Laboratory of Precision Geodesy, School of Earth and Space Sciences, University of Science and Technology of China Cheng Qian State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences Yingzhan Wei State Key Laboratory of High Pressure and Superhard Materials, College of Physics, Jilin University Xinyang Li State Key Laboratory of High Pressure and Superhard Materials, College of Physics, Jilin University Yuzhu Wang Shanghai Advanced Research Institute, Chinese Academy of Sciences Takayuki Ishii Institute for Planetary Materials, Okayama University The observed 2%–7% low-shear velocity (VS) anomalies near the subducted slab at the bottom mantle transition zone (MTZ) indicate strong lateral heterogeneity, which is commonly attributed to subducted oceanic crust. However, davemaoite, a major constituent of the subducted oceanic crust, has been poorly constrained in its elasticity, hindering accurate velocity modeling and obscuring the origin of these low-velocity features. Here we report single-crystal elasticity of Ti-bearing davemaoite with the composition of Ca(Si0.57Ti0.43)O3 under high pressure-temperature and found that Ti incorporation significantly reduces velocities and alters the pressure dependence of the shear modulus. Further velocity modeling demonstrated that subducted crusts with varying Ti content have seismic signatures of 1.7(2)–6.8(5)% low-VS at the bottom MTZ, consistent with the observed low-VS structure in the region. These findings highlight the role of slab-derived chemical heterogeneity in generating mantle seismic anomalies and provide new experimental constraints on the structure and dynamics of the deep Earth. No potential conflict of interest relevant to this article was reported.