The Wayback Machine - https://web.archive.org/web/20170702105519/http://adsabs.harvard.edu/abs/2014NatGe...7...25O
Sign on

SAO/NASA ADS Physics Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Citations to the Article (16) (Citation History)
· Refereed Citations to the Article
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks
Authors:
Ohtomo, Yoko; Kakegawa, Takeshi; Ishida, Akizumi; Nagase, Toshiro; Rosing, Minik T.
Affiliation:
AA(Natural Resources and Environmental Geochemistry Research Group, Division of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, 980-8578, Japan; ), AB(Natural Resources and Environmental Geochemistry Research Group, Division of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, 980-8578, Japan), AC(Natural Resources and Environmental Geochemistry Research Group, Division of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, 980-8578, Japan), AD(Natural Resources and Environmental Geochemistry Research Group, Division of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, 980-8578, Japan), AE(Nordic Center for Earth Evolution, Natural History Museum of Denmark, University of Copenhagen, 1350, Denmark)
Publication:
Nature Geoscience, Volume 7, Issue 1, pp. 25-28 (2014).
Publication Date:
01/2014
Origin:
NATURE
Abstract Copyright:
(c) 2014: Nature Publishing Group
DOI:
10.1038/ngeo2025
Bibliographic Code:
2014NatGe...7...25O

Abstract

Some graphite contained in the 3.7-billion-year-old metasedimentary rocks of the Isua Supracrustal Belt, Western Greenland, is depleted in 13C and has been interpreted as evidence for early life. However, it is unclear whether this graphite is primary, or was precipitated from metamorphic or igneous fluids. Here we analyse the geochemistry and structure of the 13C- depleted graphite in the Isua schists. Raman spectroscopy and geochemical analyses indicate that the schists are formed from clastic marine sediments that contained 13C-depleted carbon at the time of their deposition. Transmission electron microscope observations show that graphite in the schist occurs as nanoscale polygonal and tube-like grains, in contrast to abiotic graphite in carbonate veins that exhibits a flaky morphology. Furthermore, the graphite grains in the schist contain distorted crystal structures and disordered stacking of sheets of graphene. The observed morphologies are consistent with pyrolysation and pressurization of structurally heterogeneous organic compounds during metamorphism. We thus conclude that the graphite contained in the Isua metasediments represents traces of early life that flourished in the oceans at least 3.7billion years ago.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints
    


Morty Proxy This is a proxified and sanitized view of the page, visit original site.