发表机构
University of Hawai'i at Manoa; Institute of Science Tokyo; Japan Synchrotron Radiation Research Institute（夏威夷大学马诺阿分校; 东京科学大学; 日本同步辐射研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过高压高温实验测量干燥CaSiO3钙钛矿的电导率，发现其电导率低于此前报道、随压力降低，且无法解释下地幔高电导率异常，对下地幔整体电导率贡献小。
AI 中文摘要
电导率（EC）为地球深部地幔的成分与挥发分分布提供重要约束，而作为下地幔主要相的戴夫钙矿（CaSiO3钙钛矿）的电导率仍缺乏充分约束。我们利用激光加热金刚石对顶砧中的阻抗谱，测量了名义上干燥的CaSiO3钙钛矿在压力高达89 GPa、温度高达2200 K下的电导率。电导率随温度升高而增加，但随压力升高呈系统性降低，且显著低于此前报道值，不过与近期关于氧空位介导离子输运的理论预测大体一致。温度依赖性的显著变化与四方相到立方相的相边界重合，表明结构转变过程中离子输运有适度增强。沿正常下地幔地温梯度，干燥戴夫钙矿的电导率在下地幔顶部与布里奇曼石相当，但随深度增加导电性逐渐降低；在冷板块条件下，干燥戴夫钙矿的电导率显著低于干燥俯冲洋中脊玄武岩（MORB），无法解释观测到的高电导率异常，因此干燥戴夫钙矿对下地幔整体电导率的贡献极小。
英文摘要
Electrical conductivity (EC) provides important constraints on the composition and volatile distribution of Earth's deep mantle, yet the EC of davemaoite (CaSiO3 perovskite), a major lower-mantle phase, remains poorly constrained. We measured the EC of nominally dry CaSiO3 perovskite at pressures up to 89 GPa and temperatures up to 2200 K using impedance spectroscopy in a laser-heated diamond anvil cell. Conductivity increases with temperature but decreases systematically with pressure and it is substantially lower than previously reported, yet broadly consistent with recent theoretical predictions for oxygen-vacancy-mediated ionic transport. A distinct change in the temperature dependence coincides with the tetragonal-to-cubic phase boundary, revealing a modest enhancement of ionic transport across the structural transition. Along a normal lower-mantle geotherm, dry davemaoite is comparable in conductivity to bridgmanite near the top of the lower mantle but becomes progressively less conductive with depth. Under cold-slab conditions, dry davemaoite is substantially less conductive than dry subducted MORB and cannot account for the observed high-conductivity anomalies. Dry davemaoite therefore contributes little to bulk lower-mantle conductivity.
