Dong Xu-Han, Wang Shui-Jiong, Wang Wenzhong, Huang Shichun, Li Qiu-Li, Liu Chengshuai, Gao Ting, Li Shuguang, Wu Shitou
State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Beijing), Beijing 100083, China.
Frontiers Science Center for Deep-time Digital Earth, China University of Geosciences (Beijing), Beijing 100083, China.
Sci Adv. 2024 Aug 9;10(32):eadm8138. doi: 10.1126/sciadv.adm8138. Epub 2024 Aug 7.
Deep carbon cycle is crucial for mantle dynamics and maintaining Earth's habitability. Recycled carbonates are a strong oxidant in mantle carbon-iron redox reactions, leading to the formation of highly oxidized mantle domains and deep carbon storage. Here we report high Fe/∑Fe values in Cenozoic intraplate basalts from eastern China, which are correlated with geochemical and isotopic compositions that point to a common role of carbonated melt with recycled carbonate signatures. We propose that the source of these highly oxidized basalts has been oxidized by carbonated melts derived from the stagnant subducted slab in the mantle transition zone. Diamonds formed during the carbon-iron redox reaction were separated from the melt due to density differences. This would leave a large amount of carbon (about four times of preindustrial atmospheric carbon budget) stored in the deep mantle and isolated from global carbon cycle. As such, the amounts of subducted slabs stagnated at mantle transition zone can be an important factor regulating the climate.
深部碳循环对于地幔动力学和维持地球的宜居性至关重要。再循环碳酸盐在地幔碳 - 铁氧化还原反应中是一种强氧化剂，导致形成高度氧化的地幔区域和深部碳储存。在此，我们报告了中国东部新生代板内玄武岩中高的Fe/∑Fe值，这些值与地球化学和同位素组成相关，表明具有再循环碳酸盐特征的碳酸熔体起到了共同作用。我们提出，这些高度氧化玄武岩的源区已被源自地幔过渡带停滞俯冲板块的碳酸熔体氧化。在碳 - 铁氧化还原反应过程中形成的钻石由于密度差异而与熔体分离。这将使大量的碳（约为工业化前大气碳储量的四倍）储存在深部地幔中，并与全球碳循环隔离。因此，在地幔过渡带停滞的俯冲板块数量可能是调节气候的一个重要因素。
