Xu Rong, Cai Yue, Lambart Sarah, Chen Chunfei, Zhang Jun-Bo, Zhou Mei-Fu, Liu Jia, Bai Zhongjie, Wu Tao, Huang Feng, Ruan Ting, Liu Yongsheng
State Key Laboratory of Critical Mineral Research and Exploration, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
Sci Adv. 2025 Apr 25;11(17):eads5104. doi: 10.1126/sciadv.ads5104. Epub 2025 Apr 23.
Recycling of surficial volatiles such as carbon into the mantle plays a fundamental role in modulating Earth's habitability. However, slab devolatilization during subduction could prevent carbon from entering the deep mantle. Boron isotopes are excellent tracers of recycled volatiles, but correlations between boron isotopes and mantle heterogeneity indicators are rarely observed, thereby casting doubt that substantial amounts of volatiles and boron can be recycled into the deep mantle. Here, we show that boron isotopes in two different types of primitive continental intraplate basalts correlate well with mantle heterogeneity indicators, indicating contributions of various subducted crustal components. A common high-δB component shared by both types of basalts is best explained as recycled subducted carbonate rather than serpentinite. Our findings demonstrate that subducted carbonate carries heavy B into Earth's deep mantle, and its recycling could account for the high-δB signatures observed in intraplate magmas and deeply sourced carbonatites.
诸如碳等表层挥发性物质向地幔的再循环在调节地球宜居性方面起着根本性作用。然而，俯冲过程中的板块脱挥发作用可能会阻止碳进入深部地幔。硼同位素是再循环挥发性物质的优良示踪剂，但很少观察到硼同位素与地幔不均一性指标之间的相关性，因此有人怀疑大量挥发性物质和硼能否再循环进入深部地幔。在此，我们表明，两种不同类型的原始大陆板内玄武岩中的硼同位素与地幔不均一性指标密切相关，表明各种俯冲地壳组分的贡献。两种玄武岩共有的一个常见高δB组分，最合理的解释是再循环的俯冲碳酸盐而非蛇纹石。我们的研究结果表明，俯冲碳酸盐将重硼带入地球深部地幔，其再循环可以解释在板内岩浆和深部源碳酸岩中观察到的高δB特征。
