Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks

@article{Ohtomo2014EvidenceFB,
  title={Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks},
  author={Yoko Ohtomo and Takeshi Kakegawa and Akizumi Ishida and Toshiro Nagase and Minik T. Rosing},
  journal={Nature Geoscience},
  year={2014},
  volume={7},
  pages={25-28}
}
The Archaean rocks of Isua, West Greenland, contain graphite, but its origins are debated. Geochemical and microscopic analyses suggest that the graphite was formed from biologically formed carbon that was deposited at least 3.7 billion years ago. 

Archean Fossil Microorganisms

The article discusses materials on the Archean (4.0–2.5 Ga) microfossils of the Earth (Greenland, Australia, South Africa, and Fennoscandian Shield). The main emphasis is on the description of the

Keivy Paraschists (Archean–Early Proterozoic): Nanobacteria and Life

Nanobacteria, buried in situ, were discovered in the Early Precambrian paraschists (Keivy, Kola Peninsula). It is suggested that occurrence of nanobacteria indicates that a biological factor played a

Graphitic Carbons and Biosignatures

The unambiguous identification of graphitic carbons as remains of life in ancient rocks is challenging because fossilized biogenic molecules are inevitably altered and degraded during diagenesis and

Rise of Earth’s atmospheric oxygen controlled by efficient subduction of organic carbon

Little is known about the deep carbon cycle during the Archaean. High- pressure and -temperature experiments indicate that the subduction of organic carbon on a hotter, younger Earth was efficient,

Elements of Eoarchean life trapped in mineral inclusions

TLDR
The preservation of Eoarchean organic residues within sedimentary material corroborates earlier claims for the biogenic origins of carbon in Isua metasediments.

Biogenic and Abiogenic Graphite in Minerals and Rocks of the Early Earth

Minerals and rocks older than 3.7 billion years in age have attracted investigators looking to find evidence for traces of life. However, ancient rocks are heavily metamorphosed, leaving only

Early trace of life from 3.95 Ga sedimentary rocks in Labrador, Canada

TLDR
The large fractionation between the δ13Ccarb and δ 13Corg values, up to 25‰, indicates the oldest evidence of organisms greater than 3.95 Ga, which enables geochemical study of the biogenic materials themselves, and will provide insight into early life not only on Earth but also on other planets.

Graphitic carbons and biosignatures 2 3

<100 words) 87 Unambiguous identification of graphitic carbons as remains of life in ancient rocks 88 is challenging because fossilized biogenic molecules are inevitably altered and 89 degraded

Chlorine Isotope Composition of Apatite from the >3.7 Ga Isua Supracrustal Belt, SW Greenland

The study of the oldest surviving rock suites is crucial for understanding the processes that shaped the early Earth and formed an environment suitable for life. The metasedimentary and metavolcanic
...

References

SHOWING 1-10 OF 31 REFERENCES

13C-Depleted carbon microparticles in >3700-Ma sea-floor sedimentary rocks from west greenland

TLDR
Turbiditic and pelagic sedimentary rocks from the Isua supracrustal belt in west Greenland contain reduced carbon that is likely biogenic, which was perhaps derived from planktonic organisms.

Metasomatic Origin of Quartz-Pyroxene Rock, Akilia, Greenland, and Implications for Earth's Earliest Life

A quartz-pyroxene rock interpreted as a banded iron formation (BIF) from the island of Akilia, southwest Greenland, contains13C-depleted graphite that has been claimed as evidence for the oldest

Reassessing the evidence for the earliest traces of life

TLDR
It is shown that graphite occurs abundantly in secondary carbonate veins in the ISB that are formed at depth in the crust by injection of hot fluids reacting with older crustal rocks (metasomatism); these metasomatic rocks, which clearly lack biological relevance, were earlier thought to be of sedimentary origin.

Earliest part of Earth's stratigraphic record: A reappraisal of the >3.7 Ga Isua (Greenland) supracrustal sequence

Investigations of the Isua supracrustal rocks in West Greenland allow us to identify the protoliths and alteration history for most Isua rocks. The protoliths consisted of alternating basalt and

Constraints on graphite crystallinity in some Spanish fluid-deposited occurrences from different geologic settings

Abstract Epigenetic, vein-type graphite mineralization originates by deposition from C—O—H fluids in high-temperature environments. Consequently, fluid-deposited graphite is uniformly highly

Raman spectra of carbonaceous material in metasediments: a new geothermometer

Metasedimentary rocks generally contain carbonaceous material (CM) deriving from the evolution of organic matter originally present in the host sedimentary rock. During metamorphic processes, this

Evidence for life on Earth before 3,800 million years ago

IT is unknown when life first appeared on Earth. The earliest known microfossils (˜3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required a