References / paperEvidence for biogenic graphite in early Archaean Isua metasedimentary rocks
Ohtomo, Y.; Kakegawa, T.; Ishida, A.; Nagase, T.; Rosing, M.T.
Year2014
Source roleprimary-study
DOI / ID10.1038/ngeo2025
Fitness and scope
range · geochronology · methods
Primary field, isotope, Raman and electron-microscopy study of graphite in 3.7 Ga Isua metasediments. Its biogenic interpretation provides a sampled biosignature minimum, not a precise abiogenesis or LUCA date.
Claim ledger
fossil-range · mediumThe Life navigation envelope begins at 3.7 Ga as a conservative sampled biosignature boundary supported by biogenic-graphite evidence and extends to living Earth life at 0 Ma; 3.7 Ga is a minimum age by which life is evidenced, not a precise date for abiogenesis, LUCA or the origin of every lineage.
claim:taxon:life:fossil-range