Yu Zhiteng, Singh Satish C, Hamelin Cédric, Grenet Léa, Maia Marcia, Briais Anne, Petracchini Lorenzo, Brunelli Daniele
Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China.
Geo-Ocean UMR6538, CNRS-Ifremer-UBO-UBS, Plouzané, France.
Nat Commun. 2025 Jan 10;16(1):563. doi: 10.1038/s41467-024-55792-9.
Volatiles (CO, HO) play a fundamental role in mantle melting beneath ocean spreading centers, but what role they play during the melt migration remains unknown. Using seismological data recorded by ocean-bottom seismometers, here we report the presence of deep earthquakes at 10-20 km depth in the mantle along the Mid-Atlantic Ridge axis, much below the brittle-ductile boundary. Syntheses of regional basaltic rock samples and their geochemical analyses indicate the presence of an abnormally high quantity of CO (~0.4-3.0 wt%) in the primary melts. As the degassing of a high concentration of dissolved CO produces volume change, we suggest that deep earthquakes in the mantle result from the degassing of CO. The large concentration of CO in the primitive melt will influence the presence of melt beneath the lithosphere-asthenosphere boundary at sub-solidus temperatures.
挥发性物质（CO、H₂O）在洋中脊下方的地幔熔融过程中起着基础性作用，但它们在熔体迁移过程中扮演何种角色仍不清楚。利用海底地震仪记录的地震数据，我们在此报告，在大西洋中脊轴下地幔10 - 20千米深处存在深源地震，该深度远低于脆韧性边界。对区域玄武岩岩石样本的综合分析及其地球化学分析表明，原生熔体中存在异常高含量的CO（约0.4 - 3.0 wt%）。由于高浓度溶解CO的脱气会产生体积变化，我们认为地幔中的深源地震是由CO脱气导致的。原始熔体中大量的CO会影响岩石圈 - 软流圈边界以下亚固相线温度下熔体的存在。
