Rasmussen B
Department of Geology and Geophysics, University of Western Australia, Nedlands, Australia.
Nature. 2000 Jun 8;405(6787):676-9. doi: 10.1038/35015063.
The record of Archaean microfossils is sparse. Of the few bona fide fossil assemblages, most are from shallow-water settings, and they are typically associated with laminated, stromatolitic sedimentary rocks. Microfossils from deep-sea hydrothermal systems have not been reported in Precambrian rocks (> 544 million years old), although thermophilic microbes are ubiquitous in modern sea-floor hydrothermal settings, and apparently have the most ancient lineages. Here, I report the discovery of pyritic filaments, the probable fossil remains of thread-like microorganisms, in a 3,235-million-year-old deep-sea volcanogenic massive sulphide deposit from the Pilbara Craton of Australia. From their mode of occurrence, the micro-organisms were probably thermophilic chemotropic prokaryotes, which inhabited sub-sea-floor hydrothermal environments. They represent the first fossil evidence for microbial life in a Precambrian submarine thermal spring system, and extend the known range of submarine hydrothermal biota by more than 2,700 million years. Such environments may have hosted the first living systems on Earth, consistent with proposals for a thermophilic origin of life.
太古宙微化石的记录稀少。在为数不多的真正化石组合中，大多数来自浅水环境，且通常与纹层状叠层石沉积岩有关。尽管嗜热微生物在现代海底热液环境中普遍存在，且显然拥有最古老的谱系，但在前寒武纪岩石（年龄超过5.44亿年）中尚未报道过来自深海热液系统的微化石。在此，我报告在澳大利亚皮尔巴拉克拉通一处32.35亿年前的深海火山成因块状硫化物矿床中发现了黄铁矿细丝，它们可能是丝状微生物的化石遗迹。从其出现方式来看，这些微生物可能是嗜热化能营养原核生物，栖息于海底以下的热液环境中。它们代表了前寒武纪海底热泉系统中微生物生命的首个化石证据，并将已知的海底热液生物群范围扩展了超过27亿年。这样的环境可能曾是地球上最早的生命系统的栖息地，这与生命起源于嗜热环境的观点相符。
