A biomarker and δ15N study of thermally altered Silurian cyanobacterial mats
A biomarker and δ15N study of thermally altered Silurian cyanobacterial mats
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DOI：
10.1016/j.orggeochem.2008.11.008
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发表时间：
2009-02-01
影响因子：
3
通讯作者：
Damste, Jaap S. Sinninghe
中科院分区：
文献类型：
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作者：
Bauersachs, Thorsten;Kremer, Barbara;Damste, Jaap S. Sinninghe
来自圣十字和巴兹基山脉（波兰）的志留纪早期硅质岩中含有丰富的微化石，在形态上类似于当代的蓝藻。保存在硅质岩中的有机质大部分是高度成熟的，并且由于生物分解和进行性热蚀变而被广泛降解。这些过程可能改变了沉积的微生物遗骸的原始形态，因此微体化石的起源很容易被误解。因此，硅质岩进行了检查，使用有机地球化学和稳定同位素技术提供支持的蓝藻遗骸的存在。散装沉积物和可提取有机质的氮同位素组成分别为+0.1 ‰至-2.2 ‰和+1.8 ‰至1.7 ‰。因此，δ（15）N值与两个地点的固氮蓝藻的贡献非常一致。圣十字山脉的生物标志物。硅质岩包括中链支化的单甲基烷烃，表明蓝藻的贡献。然而，蓝细菌起源的分子化石没有在Bardzkie山脉中检测到。黄貂鱼，最有可能是因为更大的成熟度比那些从圣十字山。(C)2008爱思唯尔有限公司保留所有权利。
Early Silurian cherts from the Holy Cross and Bardzkie Mountains (Poland) contain abundant microfossils morphologically resembling contemporary cyanobacteria. Most of the organic matter preserved in the cherts is highly mature and extensively degraded because of biological decomposition and progressive thermal alteration. These processes may have changed the original morphology of the deposited microbial remains, so the microfossil origin could be easily misinterpreted. The cherts were therefore examined using organic geochemical and stable isotope techniques to provide support for the presence of cyanobacterial remains. The nitrogen isotopic composition of bulk sediments and extractable organic matter ranged from +0.1 parts per thousand, to -2.2 parts per thousand and from +1.8 parts per thousand to 1.7 parts per thousand, respectively. The delta(15)N values are thus in good agreement with a contribution of diazotrophic cyanobacteria for both locations. Biomarkers in the Holy Cross Mts. cherts included mid-chain branched monomethyl alkanes, indicative of a cyanobacterial contribution. However, Molecular fossils of a cyanobacterial origin were not detected in the Bardzkie Mts. cherts, most likely because of the greater maturity than those from the Holy Cross Mts. (C) 2008 Elsevier Ltd. All rights reserved.