Fourier transform infrared microspectroscopic characterization of Neoproterozoic organic microfossils from the Fifteenmile Group in Yukon, Canada
Fourier transform infrared microspectroscopic characterization of Neoproterozoic organic microfossils from the Fifteenmile Group in Yukon, Canada
复制标题
加拿大育空地区十五英里群新元古代有机微化石的傅里叶变换红外显微光谱表征
作者：
M. Igisu;T. Komiya;S.M. Awramik;Y. Ikemoto;Y. Geng;H. Uehara;K. Takai
将传统和基于同步辐射 (SR) 的傅立叶变换红外显微光谱 (micro-FTIR) 应用到四种类型的 ~ 810Ma 有机壁微化石以及弥漫有机质 (OM) 和来自加拿大育空地区十五英里群的一种不规则形状结构，以进行化学表征。微化石包括一种丝状类型和三种球状类型。微型 FTIR 绘图分析揭示了微化石中有机成分（脂肪族 C-H 键）和碳酸盐的微米尺度空间分布。基于 CH3/CH2 峰高比 (R3/2) 和微化石（不含扩散 OM）的形态与先前描述的元古代微化石的比较，建议了微化石可能的亲缘关系，如下。由于与含有丰富脂肪族 C-H 基团的弥散 OM 显着混合，粘球菌的特征尚未明确。不规则形状的结构可以代表真核生物。弥漫性 OM 可能代表分解的微生物细胞和胞外聚合物 (EPS) 的混合物。对两种球菌类型（盂孢菌和未命名球菌 D 型）的 SR 显微 FTIR 测量表明，盂孢菌中具有壁结构的内部斑点的 R3/2 值与无壁结构的内部斑点相似：未命名球菌 D 型的值不同。结果表明，这两种球菌在化学和形态上都不同。有机壁微化石的显微 FTIR 表征以及形态分析为了解其生物亲和力提供了新的见解。
Conventional and synchrotron radiation‐based (SR) Fourier transform infrared microspectroscopies (micro‐FTIR) were applied to four types of ~ 810 Ma organic‐walled microfossils together with diffuse organic matter (OM) and one irregularly shaped structure from the Fifteenmile Group, in Yukon, Canada, for their chemical characterization. The microfossils comprised one filamentous type and three coccoidal types. Micro‐FTIR mapping analysis revealed the micrometer‐scale, spatial distribution of organic components (aliphatic C‐H bonds) and carbonate in the microfossils. Based on comparisons of CH3/CH2peak height ratios (R3/2) and morphologies of the microfossils (without the diffuse OM) to those of previously described Proterozoic microfossils, possible affinities of the microfossils are suggested, as follows.Palaeolyngbya? andGlenobotrydionbelong to bacteria.Myxococcoidesis not clearly characterized due to the significant mixing with diffuse OM containing abundant aliphatic C‐H groups. The irregularly shaped structure may represent a eukaryote. The diffuse OM may represent a mixture of decomposed microbial cells and extracellular polymeric substances (EPS). SR micro‐FTIR measurements of two coccoid types (Glenobotrydionand Unnamed Coccoid Form D) revealed that the R3/2values of the internal spots with wall structures are similar to those without wall structures inGlenobotrydion: those values from Unnamed Coccoid Form D were different. The results suggest that these two coccoids are different chemically as well as morphologically. Micro‐FTIR characterization of the organic‐walled microfossils together with morphological analysis provides new insight into their biological affinities.