Effect of Iron on the Stability of Rhodochrosite at the Topmost Lower Mantle Conditions

作     者：Tianlei Zhai Fei Qin Shengxuan Huang Shan Qin Yu Gong Tianlei Zhai;Fei Qin;Shengxuan Huang;Shan Qin;Yu Gong

作者机构：Key Laboratory of Orogenic Belts and Crustal EvolutionMinistry of EducationSchool of Earth and Space SciencesPeking UniversityBeijing100871China School of Earth Sciences and ResourcesChina University of GeosciencesBeijing100083China Beijing Synchrotron Radiation FacilityInstitute of High Energy PhysicsChinese Academy of SciencesBeijing100049China 

出 版 物：《Journal of Earth Science》 (地球科学学刊（英文版）)

年 卷 期：2024年第35卷第2期

页      面：504-513页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 

基　　金：supported by National Natural Science Foundation of China(Nos.42072047 41772034) 

主　　题：deep carbon cycle rhodochrosite reduced mantle diamond formation high pressure tectonics geochemistry 

摘      要：Carbonates are viewed as the principal oxidized carbon carriers during subduction,and thus the stability of subducted carbonates has significant implications for the deep carbon *** we investigate the high pressure-temperature behaviors of rhodochrosite in the presence of iron up to∼34 GPa by in-situ X-ray diffraction and ex-situ Raman *** relatively low temperature below∼1500 K,MnCO_(3)breaks down into MnO and CO_(2).Upon heating to∼1800 K,however,the MnCO_(3)-Fe^(0)reactions occur with the formation of Mn_(3)O_(4),Fe^(O)and reduced carbon.A three-stage reaction mechanism is proposed to understand the kinetics of the carbon-iron-manganese redox *** results suggest that Fe^(0)can serve as a reductant to greatly affect the stability of rhodochrosite,which implies that the effect of Fe-metal should be seriously considered for the high pressure-temperature behaviors of other predominant carbonates at Earth s mantle conditions,particularly at depths greater than∼250 km.