Abiotic synthesis during the interaction of ferrous chloride-rich silicic fluids with marble under high-grade metamorphic conditions

• 成果类型: Article
• 署名作者: Fei, Chenhui; Guo, Shun; Li, Yibing; Liu, Jingbo
• 署名单位: Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Zhejiang Ocean University; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9388
• DOI: 10.1073/pnas.2423043122
• 发表日期: 2025-09-02
• 关键词: sulu uhp terrane; u-pb; phase-equilibria; subduction zones; organic-matter; kola-peninsula; high-pressures; deep-crustal; hydrocarbons; zircon

摘要

Ferrous chloride-rich silicic fluid and melt infiltration led to the decarbonation of dolomitic marble in the Chinese Sulu ultrahigh-pressure metamorphic terrain under temperatures ranging from 670 to 800 degrees C, pressures from the aragonite + albite to calcite stability fields and the oxygen fugacities between the hematite-magnetite and pyrite-pyrrhotite-magnetite buffers, resulting in the formation of olivine marble and diopsidite. The inclusions in zircons trapped during the decarbonation process suggest that the H2-producing reaction 3FeCl2 (aq) + 3CaCO3 + H2O = Fe3O4 (magnetite) + 3CaCl2 (aq) + 3CO2 + H2 occurred and that it induced magnetite-catalyzed Fischer-Tropsch-type synthesis, as indicated by the presence of whewellite, disordered carbonaceous material, CH4, and CO in the inclusions. The results of this study highlight the role of aqueous Fe in generating H2 and magnetite and have far-reaching implications for carbon speciation and solubility in deep fluids and for endogenic abiotic synthesis, which may be pivotal in the prebiotic occurrence of organic compounds on Earth.