近日，美国耶鲁大学Boriana Kalderon-Asael团队报道了自生粘土形成的埃迪卡拉风格的特殊化石。2025年12月15日出版的《地质学》杂志发表了这项成果。

埃迪卡拉生物群——地球上最早由复杂宏观生物构成的化石生态系统——对于理解前寒武纪与早古生代动物多样性辐射之间的过渡阶段具有关键意义。该生物群的大部分特异埋藏均以独特的埃迪卡拉式三维铸模形态，异常完好地保存在砂岩中。然而，导致这些软躯体生物化石化的因素——尤其是它们在成分未成熟的砂岩与异粒岩层中的保存机制——仍存在争议。

研究组通过调查加拿大纽芬兰与西北部经典埃迪卡拉生物群化石组合，探讨了粘土矿物在促进埃迪卡拉式化石保存中的埋藏学意义。结合电子显微镜、X射线衍射、主微量元素及锂同位素分析，他们发现了与这些化石伴生的碎屑性黏土矿物与早期成岩黏土矿物的证据。特别值得关注的是，研究组记录了富含铁镁的粘土矿物（包括鲕绿泥石及其他绿泥石族矿物），这可能反映了自生成岩前驱矿物（如硼镁铁矿）的存在——该类矿物在其他类型的特异埋藏中亦被证实具有关键作用。

锂同位素数据进一步证实了碎屑性黏土与海相自生黏土在塑造这些化石铸模保存中的重要性。这些研究结果为理解埃迪卡拉式化石记录的潜在形成机制提供了更广阔的视角，并表明自生粘土矿化作用可能塑造了新元古代-古生代过渡期多个特异埋藏窗口的形成条件。

附：英文原文

Title: Authigenic clays shaped Ediacara-style exceptional fossilization

Author: Lidya G. Tarhan, Thomas H. Boag, Boriana Kalderon-Asael

Issue&Volume: 2025-12-15

Abstract: The Ediacara Biota—Earth’s earliest fossilized ecosystems of complex, macroscopic organisms—has played a key role in shaping understanding of the transition between the Precambrian and early Paleozoic radiations of animal diversity. The majority of Ediacara Biota Lagersttten are exceptionally preserved in the distinctive Ediacara style as three-dimensional casts and molds in sandstones. However, the factors responsible for the fossilization of these soft-bodied organisms—in particular, for their preservation in compositionally immature sandstones and heterolithic strata—remain debated. In this study, we investigate the taphonomic importance of clay minerals in fostering Ediacara-style fossilization in classic Ediacara Biota fossil assemblages in Newfoundland and northwestern Canada. Using a combination of electron microscopy, X-ray diffraction, and major and trace element and lithium isotope analyses, we describe evidence for both detrital and early diagenetic clay minerals associated with these fossils. In particular, we document iron- and magnesium-rich clays, including chamosite and other chlorite-group minerals, which may reflect an authigenic precursor such as berthierine, a mineral that has also been implicated in other modes of exceptional preservation. Lithium isotope data corroborate the importance of detrital and marine authigenic clays in shaping the moldic preservation of these fossils. These results provide a broader view of potential drivers of the Ediacara-style fossil record and suggest that authigenic clay mineralization may have shaped multiple windows of exceptional fossilization across the NeoproterozoicPaleozoic transition.

DOI: 10.1130/G53967.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G53967.1/723271/Authigenic-clays-shaped-Ediacara-style-exceptionalredirectedFrom=fulltext