Reevaluating the earliest traces of life on Earth

我们对地球上最早期生命的性质和多样性知之甚少。在没有明确的微体化石的情况下，任何这样的信息都只能从生物脂质的沉积烃残留物中获得。最古老的岩石，其变质程度可以允许化石生物标志物的保存被发现在ca。2.7到澳大利亚皮尔巴拉克拉通的2.8 Ga Fortescue群，但由于浓度低，因此污染风险高，这种古老生物标志物的原始性备受争议。这使得之前关于太古代分子化石的报道和由此产生的器官多样性重建黯然失色，从而留下了知识真空。2012年，我们在前所未有的无烃条件下在Fortescue层序中钻了三个孔，并收集了超净岩心样品。初步分析表明，这些太古代岩石是迄今为止发现的最原始的岩石，并表明迄今为止所有的研究都受到了一些污染。我在这里建议用专门开发的方法对这些独特的样品进行全面分析，以研究地球上最古老的未受污染的碳氢化合物。研究结果将揭示从这些古老样品中提取的所有有机质和环境信息，无疑为我们了解早期前寒武纪提供了新的范式。

Exceedingly little is known about the nature and diversity of the earliest life on Earth. In the absence of unambiguous microfossils, any such information can only be gained from the sedimentary hydrocarbon remnants of biological lipids. The oldest rocks whose metamorphic grade could allow the preservation of fossil biomarkers are found in the ca. 2.7 to 2.8 Ga Fortescue Group of the Pilbara craton, Australia, but due to low concentrations and a consequently high contamination risk, the originality of such ancient biomarkers is highly debated. This has overshadowed previous reports of Archean molecular fossils and resultant reconstructions of organismic diversity, thereby leaving a knowledge-vacuum. In 2012 we drilled three holes into the Fortescue sequence under unprecedented hydrocarbon-free conditions and collected ultra-clean core samples. Preliminary analyses show that these Archean rocks are the most pristine ever recovered, and indicate that all previous studies hitherto suffered from some contamination. I here propose the comprehensive analysis of these unique samples with specifically-developed methods to study Earths oldest uncontaminated hydrocarbons. The results will reveal all organismic and environmental information that can be extracted from these ancient samples and undoubtedly set a new paradigm for our understanding of the early Precambrian.