Decarbonization of siderite in the water-rich upper mantle  

作　　者：Mengqi Guo Fangfei Li Xinyang Li Zhaodong Liu Liang Li Daoyuan Wu Qiang Zhou 

机构地区：[1]Synergetic Extreme Condition High-Pressure Science Center,State Key Laboratory of Superhard Materials,College of Physics,Jilin University,Changchun 130000,China

出　　处：《Geoscience Frontiers》2025年第1期355-362,共8页地学前缘(英文版)

基　　金：support from the National Key Research and Development Project of China(Grant No.2023YFF0804100);the National Natural Science Foundation of China(NSFC 42102030,12074141,and 12274168);supported by Jilin Provincial Science and Technology Development Project(Grants No.20210402054GH and No.20220101011JC);the Program for Jilin University Science and Technology Innovative Research Team(Grant No.2021-TD-05);National Major Science Facility Synergetic Extreme Condition User Facility Achievement Transformation Platform Construction(2021FGWCXNLJSKJ01);supported financially by the National Natural Science Foundation of China(42272041).

摘　　要：The aqueous fluids within subducted slabs have the potential to influence the form of carbonate presence and the carbon cycling process.Experiments were performed on resistive heating diamond anvil cell using siderite crystals and grains with water under conditions of pressure as high as 11.4 GPa and temperatures reaching up to 530℃.These experiments aimed to simulate geological reactions that may occur within a depth range of 340 km in subducted slabs.Raman spectroscopy was employed to monitor the reactions and microscale phenomena within the sample chamber as pressure and temperature increase.The recovered products were analyzed using scanning electron microscopy and transmission electron microscopy.The results indicate that at 0.8 GPa and 108℃,a Fischer-Tropsch Type(FTT)reaction occurred on the sample surface,resulting in the formation of organic compound formaldehyde,followed by the observation of formic acid.At higher pressure and temperature(3.5 GPa,420℃),the formation ofγ-Fe_(2)O_(3)andγ-FeOOH was observed on the sample surface,accompanied by the release of CO_(2)and H_(2).Transmission electron microscope analysis of the quenched product powders indicated that the generated iron oxides were consistent with the phases observed at high pressure and temperature conditions.High pressure and temperature dissolution experiments of siderite in water reveal that carbon may be released into the mantle wedge entirely in the form of CO_(2)in warm subducted slabs and cold subducted slabs that subduct to depths of 75 km.The released CO_(2)participates in the carbon cycle of the island arc volcanic systems in the upper mantle at depths of 70-120 km and accelerates the transfer of subducted carbon to the Earth’s surface.

关 键 词：SIDERITE WATER DISSOLUTION Decarbonization Carbon dioxide Carbon cycle 

分 类 号：TG6[金属学及工艺—金属切削加工及机床]