Filamentous cyanobacteria fossils and their significance in the Permian-Triassic boundary section at Laolongdong, Chongqing
Filamentous cyanobacteria fossils and their significance in the Permian-Triassic boundary section at Laolongdong, Chongqing
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DOI：
10.1007/s11434-008-0172-1
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发表时间：
2008-06
影响因子：
--
通讯作者：
Hongxia Jiang;Yasheng Wu;C. Cai
中科院分区：
文献类型：
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作者：
Hongxia Jiang;Yasheng Wu;C. Cai
二叠纪末大规模灭绝后立即繁荣的微生物群落代表了异常极端的环境，并且在不同地区存在差异。本研究在重庆老龙洞著名的二叠纪-三叠纪交界地段的灭绝后地层中发现了丝状蓝藻生物群。在薄片中，丝状蓝藻化石长度在1毫米以下，一般向一端逐渐变细，最宽直径可达0.08毫米。有的呈弧形，表明其生活中是柔软的。它们的壁由隐晶质到微晶方解石组成。丝状物的横截面为圆形，内部充满微晶和细晶方解石，这表明丝状物原本是空的。它们随机分布在岩石中，但在某些地方，它们往往呈放射状分布。该丝状生物在形态上与蓝藻门Rivulariaceae的Rivularia相似，但具有钙化鞘，暂定为Rivularia中的一个不确定新种：Rivulariasp。蓝细菌是光合作用自养生物，可以在缺氧条件下生存。这种生物的开花和其他生物的缺乏可能表明环境缺氧且浅，因为这种光合自养生物需要生活在光带内。
The microbial communities blooming immediately after the end-Permian mass extinction represent abnormally extreme environments, and vary in different areas. In this study, filamentous cyanobacterial biota was found in the strata after the extinction in the famous Permian-Triassic boundary section at Laolongdong, Chongqing, southwest China. In thin sections, the filamentous cyanobacterial fossils are below 1 mm in length, and generally taper to one end, with the widest diameter up to 0.08 mm. Some of them are curved, indicating that they are soft in life. Their walls are composed of cryptocrystalline to microcrystalline calcites. The filaments have round cross section, and are internally filled with micrites and fine sparry calcites, which indicate that the filaments are originally empty. They are randomly distributed in the rocks, but in some places, they tend to be distributed in radial pattern. The filamentous organisms are morphologically similar toRivulariaof Rivulariaceae, Cyanobacteria Phylum, but with calcified sheaths, and are tentatively regarded as an indeterminate new species inRivularia: Rivulariasp. Cyanobacteria are photosynthetic autotrophic, and can survive in dysoxic condition. The blooming of this organism and the absence of other organisms may indicate that the environment was oxygendeficient and shallow, since this photosynthetic autotrophic organism needed to live within photic zone.