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Nature Geoscience | Volume 18 | April 2025 | 365–369 365nature geosciencehttps://doi.org/10.1038/s41561-025-01657-9 ArticlePersistence of davemaoite at lower-mantle conditions Lin Wang    , Nobuyoshi Miyajima   , Fei Wang    & Tomoo Katsura   The lower mantle occupies over half of Earth’s volume, and accordingly, its mineralogy is crucial in determining the structure and dynamics of Earth. Davemaoite, the calcium silicate perovskite, was believed to coexist with bridgmanite in the lower mantle and is considered essential for understanding the chemical evolution and dynamics of Earth’s lower mantle. However, the presence of davemaoite is challenged due to the potential for high calcium silicate solubility in bridgmanite. Here we use an ultrahigh-pressure multi-anvil technique to show experimentally that the calcium solubility in bridgmanite is insuf f i cient to eliminate davemaoite under mantle conditions, including typical mantle pressure, temperature and chemical compositions. We conclude that davemaoite has been stable in Earth’s lower mantle since its formation. Due to the limited calcium solubility in bridgmanite, davemaoite-enriched domains are expected at the core–mantle boundary. These domains could serve as the principal reservoir for incompatible elements in the lower mantle and may be the source for some ocean island basalts. Furthermore, our study of f ers an explanation for the observed large low-shear-wave-velocity provinces at the bottom of the lower mantle. These provinces may consist of davemaoite-enriched materials crystallized from basal magma ocean in early Earth history.Davemaoite (Dvm), the calcium silicate (CaSiO 3 ) perovskite, exhib -its distinctive physical and chemical properties that contribute to our understanding of the chemical evolution and dynamics of Earth’s mantle. Its low seismic velocity offers a possible explana-tion for the observed low-seismic-velocity signatures 1 and the large low-shear-wave-velocity provinces (LLSVPs) 2 at the top and bottom of the lower mantle, respectively. Its low viscosity provides an intrin-sic mechanism for delaminating slab materials and for accumulating recycled oceanic crust either at the boundary between the upper and lower mantles or at the core–mantle boundary 3 . Dvm is also well known as a geochemical reservoir for large-ion incompatible elements in the lower mantle 4 and inferred to contribute to the geochemical diversity observed in ocean island basalts 5,6 . It is the last crystallized phase dur-ing magma ocean solidification 7–9 and therefore affects the element distribution in Earth’s mantle.However, the fundamental question of the existence of Dvm in the lower mantle remains under debate. Some studies have suggested that the solubility of CaSiO 3 in (Mg,Fe)(Al,Si)O 3 bridgmanite (Bdm, the most abundant mineral in the lower mantle), expressed as χ Ca , here defined as the Ca content in cation units normalized to 2, is too low to make Dvm completely dissolve into Bdm 10–12 . These studies proposed that Dvm is the third most abundant phase in the lower mantle 10,13,14 . Other studies 15–17 , however, have reported that χ Ca increases markedly with temperature or Fe content in Bdm, leading to the conclusion that Dvm is absent in hot or oxidized regions in Earth’s lower mantle. Therefore, it remains uncertain whether Dvm exists in the lower mantle.In this Article, we systematically investigate the χ Ca under the lower-mantle conditions using our ultrahigh-pressure multi-anvil tech-nique 18 at pressures from 27 to 50 GPa and temperatures from 2,300 to 2,700 K. Five different starting materials (Extended Data Table 1) with compositions of Ca 0.5 Mg 0.5 SiO 3 (Ca50), Ca 0.04 Mg 0.85 Fe 0.10 SiO 3 (Ca4Fe10), Ca 0.08 Mg 0.80 Fe 0.10 SiO 3 (Ca8Fe10), Ca 0.08 Mg 0.70 Fe 0.11 Al 0.11 Si 0.98 O 3.1 (Fe11Al11) and Ca 0.5 Mg 0.3 Fe 0.2 Al 0.2 Si 0.8 O 3 (Fe20Al20) are used to study the compo-sition effect. Details of our experimental procedures can be found in Received: 22 August 2024Accepted: 6 February 2025Published online: 28 February 2025 Check for updatesBayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany.  e-mail: lin.wang@uni-bayreuth.de