Elasticity of davemaoite as a primary contributor to lower-mantle heterogeneities

• 成果类型: Article
• 署名作者: Zhou, Wen-Yi; Hao, Ming; Su, Wenhao; Kim, Taehyun; Chen, Sibo; Shim, Sang-Heon; Zhang, Dongzhou; Nguyen, Phuong Q. H.; Armstrong, Katherine; Zhang, Jin S.
• 署名单位: Texas A&M University System; Texas A&M University College Station; University of Bayreuth; Swiss Federal Institutes of Technology Domain; ETH Zurich; Arizona State University; Arizona State University-Tempe; University of Chicago; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; University of California System; University of California Santa Cruz
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8075; 1095-9203
• DOI: 10.1126/science.adx8356
• 发表日期: 2025-11-27
• 页码: 935-939
• 关键词: EARTHS LOWER MANTLE; high-pressure; SILICATE PEROVSKITE; SEISMIC SCATTERERS; CASIO3 PEROVSKITE; PHASE-TRANSITION; iron; velocity; melt; temperature

摘要

Geophysical detection of subducted mid-ocean ridge basalt (MORB) in the lower mantle is hindered by uncertainties in the elasticity of Fe,Al,Mg,Ti-bearing davemaoite, a key MORB component. Using Brillouin spectroscopy and x-ray diffraction, we determined the elasticity of a Ca0.906(1)Fe2+0.027(1)Fe3+0.042(1)Mg0.033(1)Al0.072(1)Ti0.020(1)Si0.912(1)O3 davemaoite up to 113 gigapascals and 2294 K. We found that it exhibited a shear wave velocity 10 to 20% slower than end-member davemaoite, making it the slowest phase among major lower-mantle minerals. Our models show that MORB, containing 20 to 25 volume percent davemaoite, potentially contributes to large low-shear-velocity provinces (LLSVPs), whereas a cumulate layer enriched in davemaoite crystallized from basal magma ocean may comprise ultralow-velocity zones (ULVZs). Davemaoite's ability to host incompatible and heat-producing elements possibly links LLSVPs and ULVZs to mantle plume initiation and geochemical signatures of ocean island basalts.