早期古細(xì)菌頁(yè)巖和粉砂巖沉積物中較大的、細(xì)胞樣結(jié)構(gòu)的發(fā)現(xiàn),，為認(rèn)為非常早的時(shí)候地球上就有多樣化活生物體的觀點(diǎn)增添了新證據(jù)。有關(guān)這樣古老的化石的說(shuō)法經(jīng)常存在爭(zhēng)議,，因?yàn)榉巧镞^(guò)程可產(chǎn)生生物類微結(jié)構(gòu)和化學(xué)特征,，與活生物體中的相似。
因此,，為了排除這些微結(jié)構(gòu)的非生物來(lái)源,，研究人員進(jìn)行了廣泛努力。它們通過(guò)了這種排查,，結(jié)果表明它們似乎是有有機(jī)壁的微化石,，來(lái)自大型微生物,，這些微生物與以前所報(bào)告的、生活在距今約32億年前的地球早期海洋里陽(yáng)光能夠照射到的淺層海水中的微生物墊共生,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 463, 934-938 (18 February 2010) | doi:10.1038/nature08793
Organic-walled microfossils in 3.2-billion-year-old shallow-marine siliciclastic deposits
Emmanuelle J. Javaux1, Craig P. Marshall2 & Andrey Bekker3
1 Department of Geology, University of Liège, 17 allée du 6 Ao?t B18, Liège 4000, Belgium
2 Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence, Kansas 66044, USA
3 Department of Geological Sciences, University of Manitoba, 125 Dysart Road (Wallace Building), Winnipeg, Manitoba R3T 2N2, Canada
Correspondence to: Emmanuelle J. Javaux1 Correspondence and requests for materials should be addressed to E.J.
Although the notion of an early origin and diversification of life on Earth during the Archaean eon has received increasing support in geochemical, sedimentological and palaeontological evidence, ambiguities and controversies persist regarding the biogenicity and syngeneity of the record older than Late Archaean1, 2, 3. Non-biological processes are known to produce morphologies similar to some microfossils4, 5, and hydrothermal fluids have the potential to produce abiotic organic compounds with depleted carbon isotope values6, making it difficult to establish unambiguous traces of life. Here we report the discovery of a population of large (up to about 300?μm in diameter) carbonaceous spheroidal microstructures in Mesoarchaean shales and siltstones of the Moodies Group, South Africa, the Earth’s oldest siliciclastic alluvial to tidal-estuarine deposits7. These microstructures are interpreted as organic-walled microfossils on the basis of petrographic and geochemical evidence for their endogenicity and syngeneity, their carbonaceous composition, cellular morphology and ultrastructure, occurrence in populations, taphonomic features of soft wall deformation, and the geological context plausible for life, as well as a lack of abiotic explanation falsifying a biological origin. These are the oldest and largest Archaean organic-walled spheroidal microfossils reported so far. Our observations suggest that relatively large microorganisms cohabited with earlier reported benthic microbial mats8 in the photic zone of marginal marine siliciclastic environments 3.2 billion years ago.
