Fluid-deposited graphite and its geobiological implications in early Archean gneiss from Akilia, Greenland

• Published in: Geobiology
• Main Authors: Lepland, A., van Zuilen, M., Philippot, Pascal
• Other Authors: Geological Survey of Norway (NGU), Tallinn University of Technology (TTÜ), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), University of Bergen (UiB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SDE]Environmental Sciences; Greenland
• Online Access: https://hal.science/hal-03886252; https://doi.org/10.1111/j.1472-4669.2010.00261.x

International audience Graphite, interpreted as altered bioorganic matter in an early Archean, ca. 3.83-Ga-old quartz-amphibole-pyroxene gneiss on Akilia Island, Greenland, has previously been claimed to be the earliest trace of life on Earth. Our petrographic and Raman spectroscopy data from this gneiss reveal the occurrence of graphitic material with the structure of nano-crystalline to crystalline graphite in trails and clusters of CO₂, CH₄ and H₂O bearing fluid inclusions. Irregular particles of graphitic material without a fluid phase, representing decrepitated fluid inclusions are common in such trails too, but occur also as dispersed individual or clustered particles. The occurrence of graphitic material associated with carbonic fluid inclusions is consistent with an abiologic, fluid deposited origin during a poly-metamorphic history. The evidence for fluid-deposited graphitic material greatly complicates any claim about remnants of early life in the Akilia rock.