Interactions between Ediacaran animals and microbial mats: Insights from Lamonte trevallis, a new trace fossil from the Dengying Formation of South China
Interactions between Ediacaran animals and microbial mats: Insights from Lamonte trevallis, a new trace fossil from the Dengying Formation of South China
复制标题
埃迪卡拉动物与微生物垫之间的相互作用：来自华南灯影组新遗迹化石Lamonte trevallis的见解
DOI：
10.1016/j.palaeo.2013.12.026
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发表时间：
2014-02-15
影响因子：
3
通讯作者：
Yuan, Xunlai
中科院分区：
文献类型：
--
作者：
Meyer, Mike;Xiao, Shuhai;Yuan, Xunlai
正式描述了华南三峡地区埃迪卡拉系灯影组上部石板滩段灰岩中的一个新的物种属和物种种Lamonte trevallis。它的特点是水平隧道与短垂直洞穴和地面小径相连。水平洞穴的横截面呈椭圆形或带褶皱状，保存完整，内部充满碳酸盐岩、微晶石以及方解石和硅胶结物。它们仅出现在粉质、褶皱和微层压层中，这些层被解释为混合的蓝细菌微生物垫；在与微层压层相邻的碎屑内层中没有发现洞穴。垂直痕迹填充了与洞穴相同的材料，但它们通常穿过起皱的微层突出并暴露在垫层表面上。表面痕迹始终保留在负上浮雕或正下浮雕中，并由两个平行系列的尖锐划痕或小旋钮组成。洞穴填充物的 delta O-18（碳水化合物）和 delta C-13（碳水化合物）值不同于微层压层和内碎屑层，但介于两者之间，这与洞穴填充物由早期碳酸盐胶结物、内碎屑和微晶的混合物组成的岩相观察结果一致。层理面生物扰动强度（20-40%）——以被 L. trevallis 痕迹覆盖的层理面面积的百分比测量，与前三叶虫寒武纪碳酸盐的类似测量结果相当。 L trevallis 在微生物垫中的独特存在可能具有埋藏学和生态学意义。这些垫子可能提供了坚固的基质和局部地球化学条件，有助于洞穴结构的完整性，它们也可能促进了洞穴填充物的早期成岩胶结，从而促进了洞穴的保存。这些洞穴与微生物垫的密切联系表明微量生产者积极开采蓝藻垫以利用氧气或营养资源。与许多其他埃迪卡拉追踪者相比，鲹鱼的追踪者能够更好地利用周围的资源，并提供了农业革命初期埃迪卡拉晚期海洋繁荣的底栖生态的地名记录。 (C) 2013 Elsevier B.V. 保留所有权利。
A new ichnogenus and ichnospecies, Lamonte trevallis, is formally described from the Shibantan Member limestone of the upper Ediacaran Dengying Formation, Yangtze Gorges area, South China. It is characterized by horizontal tunnels connected with short vertical burrows and surface trails. The horizontal burrows are elliptical or bibbed in transverse cross-section, preserved in full relief, and filled with carbonate intradasts, micrites, as well as calcite and silica cements. They occur exclusively in silty, crinkled, and microlaminated layers that are interpreted as amalgamated cyanobacterial microbial mats; no burrows have been found in intraclastic layers adjacent to the microlaminated layers. The vertical traces are filled with the same material as the burrows, but they typically project through the crinkled microlaminae and are exposed on the bedding surface. The surface tracks are always preserved in negative epirelief or positive hyporelief and consist of two parallel series of either sharp scratch marks or small knobs. The burrow infill has delta O-18(carb) and delta C-13(carb) values distinct from, but intermediate between, microlaminated and intraclastic layers, consistent with petrographic observation that burrow infill consists of a mixture of early carbonate cements, intraclasts, and micrites. Bedding plane bioturbation intensity (20-40%)-measured as percentage of bedding plane area covered by L. trevallis traces is comparable to similar measurements in pre-trilobite Cambrian carbonates. The exclusive occurrence of L trevallis within microbial mats may have both taphonomic and ecological significance. These mats may have provided firm substrates and localized geochemical conditions that contributed to the structural integrity of the burrows, and they may have also facilitated early diagenetic cementation of burrow infill, thus facilitating burrow preservation. The close association of these burrows with microbial mats implies that the trace producers actively mined cyanobacterial mats to exploit oxygen or nutrient resources. The trace makers of L trevallis were better able to utilize the resources around them than many other Ediacaran trace makers and provide an ichnological record of a flourishing benthic ecology in late Ediacaran oceans at the dawn of the agronomic revolution. (C) 2013 Elsevier B.V. All rights reserved.