Carbonate-hosted Avalon-type fossils in arctic Siberia
Carbonate-hosted Avalon-type fossils in arctic Siberia
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DOI：
10.1130/g24946a.1
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发表时间：
2008-10-01
期刊：
影响因子：
5.8
通讯作者：
Kochnev, Boris B.
中科院分区：
文献类型：
--
作者：
Grazhdankin, Dmitriy V.;Balthasar, Uwe;Kochnev, Boris B.
Avalon型化石对于理解显生宙生态系统的起源至关重要，但它们经常出现在火山碎屑和硅屑相中，极大地限制了它们的古生物分辨率。独特的碳酸盐寄主。位于西伯利亚中北部Olenek隆起的Khatyspyt组的组合，预示着这些神秘生物的解剖和古生态图景得到了极大的增强。Avalon类型的化石通过自生碳酸盐胶结作用保存在细层状结核石灰岩(Khatyspyt-type Taphonomic Window)中。互层硅化钙质泥岩产生不同的碳质挤压，偶尔伴有Avalon型分类群的埋藏性幻影(苗河型埋藏学窗口)。霉菌保存方式似乎不具有分类选择性，因此不能单独解释埃迪卡拉纪宏大化石的形态特殊性和化石组合之间在分类组成上的巨大差异。另一方面，将Avalon型化石排除在碳质挤压(苗河型保存窗)之外是一个真正的挖掘生物学信号，它对某些埃迪卡拉纪组织的性质提供了重要的限制。
Avalon-type fossils are crucial to understanding the origin of Phanerozoic ecosystems, but their usual occurrence in volcaniclastic and siliciclastic facies greatly limits their paleobiological resolution. The unique carbonate-hosted. assemblage of the Khatyspyt Formation, on the Olenek uplift of north-central Siberia, promises a much enhanced anatomical and paleoecological view of these enigmatic organisms. Avalon-type fossils are preserved by authigenic carbonate cementation in intervals of finely laminated nodular limestones (Khatyspyt-type taphonomic window). Interbedded silicified calcareous mudstones yield diverse carbonaceous compressions, occasionafly with taphonomic phantoms of Avalon-type taxa (Miaohetype taphonomic window). Styles of moldic preservation do not appear to be taxon selective, and therefore cannot alone be responsible for the morphological distinctiveness of Ediacaran macrofossils and the profound disparity in the taxonomic composition between fossil assemblages. On the other hand, the exclusion of Avalon-type fossils from carbonaceous compressions (Miaohe-type preservational window) is a real taphonomic signal that provides an important constraint on the properties of certain Ediacaran tissues.