Programa de Pós-Graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos, Washington Luiz, 325km, São Carlos, SP, 13565-905, Brazil.
Unité Mixte de Recherche (UMR), Centre National de la Recherche Scientifique (CNRS), IC2MP 7285, University of Poitiers, 86073, Poitiers, France.
Sci Rep. 2021 Mar 3;11(1):5013. doi: 10.1038/s41598-021-84433-0.
The early evolution of metazoans has been reconstructed by studies on exceptionally preserved molds in siliciclastic rocks from the Ediacaran Period. However, there remains considerable controversy regarding the formation mechanisms of this unusual 'Ediacaran-style' preservation. Proposed hypotheses usually include early authigenesis of minerals, but evidence for this is scarce. In a recently discovered deposit of Ediacaran biota in Brazil, we show that the classic moldic preservation is related to clay mineral authigenesis. Specifically, these clays originated from the alteration of original pyroclastic sediments, likely enhanced by microbial activity, leading to early illitization and morphological templating of the fossiliferous surfaces at a micrometric scale. Such high-fidelity preservation was made possible by rapid burial during volcanic events and the in-situ templating of tissue by clays via microbially-mediated mineralization. This newly described Lagerstätte demonstrates that a number of minerals can facilitate preservation, and that perhaps 'Ediacaran-style' preservation result from different processes leading to the same broad style of preservation.
后生动物的早期演化是通过对埃迪卡拉纪硅质碎屑岩中保存极好的模具的研究重建的。然而，对于这种不寻常的“埃迪卡拉式”保存的形成机制仍存在相当大的争议。提出的假说通常包括矿物质的早期自生作用，但这方面的证据很少。在巴西最近发现的埃迪卡拉生物群沉积物中，我们表明经典的模具保存与粘土矿物的自生作用有关。具体来说，这些粘土起源于原始火山碎屑沉积物的蚀变，可能是微生物活动增强的结果，导致化石表面在微米尺度上的早期伊利石化和形态模板化。这种高保真度的保存是通过火山事件期间的快速埋藏和粘土通过微生物介导的矿化对组织的原位模板化实现的。这个新描述的化石遗址表明，许多矿物质可以促进保存，也许“埃迪卡拉式”保存是由不同的过程导致的，这些过程导致了相同的广泛的保存风格。
