The 1.88-billion-year-old Gunflint carbonaceous microfossils are renowned for their exceptional morphological and chemical preservation, attributed to early and rapid entombment in amorphous silica. The carbonaceous matter lining and partly filling filamentous and spherical structures is interpreted to be indigenous, representing thermally altered relicts of cellular material (i.e., kerogen). Here we show that stromatolitic black cherts from the Gunflint Formation, Schreiber Beach, Ontario, Canada, were saturated in syn-sedimentary oil. The thermally altered oil (pyrobitumen), which occurs in the stromatolites and intercolumn sediments, fills pores and fractures, and coats detrital and diagenetic grain surfaces. The occurrence of detrital bitumen grains in the stromatolites points to the proximity of shallow seafloor oil seeps and hence the possible existence of chemosynthetic microbes degrading hydrocarbons. We suggest that hydrocarbons that migrated through the silicifying stromatolites infiltrated semi-hollow microbial molds that formed following silica nucleation on the walls or sheaths of decayed cells. Upon heating, the hydrocarbons were transformed to nanoporous pyrobitumen, retarding silica recrystallization and enhancing detailed preservation of the carbon-rich microfossils. Hydrocarbon infiltration of silicified microbes offers a new explanation for the preservation of the Gunflint microfossils and may have played a role in the formation of some of Earth's oldest microfossils.

中文翻译：

---

古代石油作为 18.8 亿年前 Gunflint 叠层石和微化石中碳质物质的来源

有 18.8 亿年历史的 Gunflint 碳质微化石以其卓越的形态和化学保存而闻名，这归因于早期快速埋藏在无定形二氧化硅中。内衬和部分填充的丝状和球形结构的碳质物质被解释为是本土的，代表细胞物质的热变遗迹（即，干酪根）。在这里，我们展示了来自加拿大安大略省施赖伯海滩 Gunflint 地层的叠层石黑色燧石在同沉积油中饱和。发生在叠层石和柱间沉积物中的热变油（pyrobitumen）填充孔隙和裂缝，并覆盖碎屑和成岩颗粒表面。叠层石中碎屑沥青颗粒的出现表明靠近浅层海底石油渗漏，因此可能存在降解碳氢化合物的化学合成微生物。我们建议通过硅化叠层石迁移的碳氢化合物渗透到半空心微生物模具中，这些微生物模具是在腐烂细胞的壁或鞘上的二氧化硅成核后形成的。加热后，碳氢化合物转化为纳米多孔焦沥青，延缓二氧化硅重结晶并加强对富含碳的微化石的详细保存。硅化微生物的碳氢化合物渗透为冈弗林特微化石的保存提供了新的解释，并且可能在地球上一些最古老的微化石的形成中发挥了作用。