Trace fossils and substrates of the terminal Proterozoic-Cambrian transition: Implications for the record of early bilaterians and sediment mixing
Trace fossils and substrates of the terminal Proterozoic-Cambrian transition: Implications for the record of early bilaterians and sediment mixing
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DOI：
10.1073/pnas.202322499
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发表时间：
2002-10-01
影响因子：
11.1
通讯作者：
Gehling, JG
中科院分区：
文献类型：
--
作者：
Droser, ML;Jensen, S;Gehling, JG
遗迹化石记录在确定两侧对称动物出现的时间方面很重要。一个保守的估计把这个时间大约在5.55亿年前。靠近沉积物-水界面的痕迹的澄清潜力对于探测早期海底活动至关重要。我们对最早寒武纪沉积物的研究表明，浅地层保存在更大的程度上比典型的大多数中生代，这可以直接和间接地归因于低水平的沉积物混合。低水平的沉积物混合意味着薄事件床被保存。沉积物混合的深度较浅，这也意味着泥质沉积物在接近沉积物-水界面的地方很坚固，增加了在泥质沉积物中记录浅层遗迹化石的可能性。总的来说，遗迹化石可以提供两侧底栖活动开始的可靠记录。
The trace fossil record is important in determining the timing of the appearance of bilaterian animals. A conservative estimate puts this time at approximate to555 million years ago. The preservational potential of traces made close to the sediment-water interface is crucial to detecting early benthic activity. Our studies on earliest Cambrian sediments suggest that shallow tiers were preserved to a greater extent than typical for most of the Phanerozoic, which can be attributed both directly and indirectly to the low levels of sediment mixing. The low levels of sediment mixing meant that thin event beds were preserved. The shallow depth of sediment mixing also meant that muddy sediments were firm close to the sediment-water interface, increasing the likelihood of recording shallow-tier trace fossils in muddy sediments. Overall, trace fossils can provide a sound record of the onset of bilaterian benthic activity.