Tarhan Lidya G, Hood Ashleigh V S, Droser Mary L
Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA.
School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, Victoria, Australia.
Geobiology. 2025 Mar-Apr;23(2):e70017. doi: 10.1111/gbi.70017.
The processes responsible for the fossilization of the Ediacara Biota-Earth's earliest fossil record of communities of complex, multicellular organisms-have long been debated. On the basis of both geologic and experimental investigations, recent studies have proposed that early diagenetic silica cementation may have been pivotal to the moldic preservation in sandstone ("Ediacara-style preservation") of fossil assemblages from the eponymous Ediacara Member of South Australia. However, the extent to which early silica cementation can explain other instances of Ediacara-style fossilization in units recording disparate depositional environments, paleogeographies, and geologic ages has not been previously constrained. Herein, we present new paleontological, petrographic, and geochemical data from a range of Ediacara-style fossil assemblages, encompassing a variety of Ediacaran and Cambrian macroorganism morphologies, ecologies, and taxonomic affinities, as well as sedimentary records of organic substrates and the macrofaunal interactions they record. These data indicate that the early diagenetic formation of silica cements was a widespread phenomenon in Ediacaran and Cambrian sandy seafloor environments and likely played a pivotal role in the preservation of these exceptional fossil assemblages. Moreover, the persistence of Ediacara-style fossilization linked to authigenic silica cementation into Cambrian strata provides new evidence that the end-Ediacaran disappearance of the Ediacara Biota was due to evolutionary rather than taphonomic phenomena.
埃迪卡拉生物群是地球上最早的复杂多细胞生物群落的化石记录，其石化过程长期以来一直存在争议。基于地质和实验研究，最近的研究表明，早期成岩作用的硅质胶结作用可能对南澳大利亚同名埃迪卡拉组化石组合在砂岩中的铸型保存（“埃迪卡拉式保存”）起到了关键作用。然而，早期硅质胶结作用能够解释记录不同沉积环境、古地理和地质年代的地层中其他埃迪卡拉式化石形成实例的程度，此前尚未得到限制。在此，我们展示了一系列埃迪卡拉式化石组合的新古生物学、岩石学和地球化学数据，涵盖了各种埃迪卡拉纪和寒武纪大型生物的形态、生态和分类亲缘关系，以及有机底物的沉积记录和它们所记录的大型动物相互作用。这些数据表明，硅质胶结物的早期成岩形成在埃迪卡拉纪和寒武纪砂质海底环境中是一种普遍现象，并且可能在保存这些特殊化石组合方面发挥了关键作用。此外，与自生硅质胶结作用相关的埃迪卡拉式化石形成持续到寒武纪地层，这提供了新的证据，表明埃迪卡拉生物群在埃迪卡拉纪末期的消失是由于进化而非埋藏学现象。
