School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
Sci Adv. 2023 Feb 3;9(5):eadd7925. doi: 10.1126/sciadv.add7925. Epub 2023 Feb 1.
Carbon is the key element of life, and its origin in ancient sedimentary rocks is central to questions about the emergence and early evolution of life. The oldest well-preserved carbon occurs with fossil-like structures in 3.5-billion-year-old black chert. The carbonaceous matter, which is associated with hydrothermal chert-barite vent systems originating in underlying basaltic-komatiitic lavas, is thought to be derived from microbial life. Here, we show that 3.5-billion-year-old black chert vein systems from the Pilbara Craton, Australia contain abundant residues of migrated organic carbon. Using younger analogs, we argue that the black cherts formed during precipitation from silica-rich, carbon-bearing hydrothermal fluids in vein systems and vent-proximal seafloor sediments. Given the volcanic setting and lack of organic-rich sediments, we speculate that the vent-mound systems contain carbon derived from rock-powered organic synthesis in the underlying mafic-ultramafic lavas, providing a glimpse of a prebiotic world awash in terrestrial organic compounds.
碳是生命的关键元素，其在古代沉积岩中的起源是生命起源和早期演化问题的核心。最古老的保存完好的碳与 35 亿年前黑色硅质岩中的化石状结构一起出现。这种碳质物质与源自下部玄武质-科马提岩熔岩的热液硅质-重晶石喷口系统有关，被认为源自微生物生命。在这里，我们表明澳大利亚皮尔巴拉克拉通 35 亿年前的黑色硅质岩脉系统含有丰富的迁移有机碳残留物。使用较年轻的类似物，我们认为黑色硅质岩是在富含硅和碳的热液流体从脉系统和喷口近海底沉积物中沉淀过程中形成的。鉴于火山环境和缺乏富含有机物的沉积物，我们推测喷口丘系统中含有源自下部镁铁质-超镁铁质熔岩中岩石驱动的有机合成的碳，这让我们一窥充满陆地有机化合物的前生物世界。
