Research Report

The generality of preservation of organic remains in body fossils by FTIR spectra

Timothy D. Huang,1,2 Yao-Chang Lee,3 Cheng-Cheng Chiang3, Robert R. Reisz1,2,4

1College of Life Sciences, National Chung Hsing University, Taichung, Taiwan, China

2DERC and ICFS of Jilin University, Changchun, Jilin 130012, China

3National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, China

4Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada

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Each chemical bond has unique vibration energy, which yields a certain characteristic peak(s) in Fourier-Transform Infrared Spectroscopy (FTIR). The alkyl (CH3-, CH2-) functional group, which exists in almost all organic compounds, will show two or more distinct absorption peaks in the 2800-3000 cm-1 range. Thus, if a given spectrum shows these peaks, we can safely say that the specimen contains the alkyl structure(s), which means organic compounds. Alkyl peaks can be used as a positive screening indicator without diving into the other IR spectra section. The overtone peaks, shapes, and intensity of carbonates in the 2800-3000cm-1 range are different from the alkyl group. This paper uses FTIR, including synchrotron radiation sr-FTIR, to examine 63 fossil specimens spanning across a long geological time and different taphonomic conditions and 15 extant specimens and nine matrices for comparisons. Each specimen was FTIR scanned multiple times. A total of 107 spectra were selected from 525 scans. The results indicate that preservation of organic remains in body fossils is a common phenomenon, not a particular case.

Key words:  FTIR, Organic Remains, Body Fossils.
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