The use of fluorescence microscopy in the characterisation of amorphous organic matter

Abstract

The organic content of a sediment can easily be identified microscopically, either by viewing kerogen concentrates in transmitted light, or reflected light measurements on whole rock samples using white light or ultraviolet excitation, provided that the material has a well defined morphology. However, in many samples the organic matter is present in an amorphous form. The origin of such material is difficult to determine, and hence the source rock potential of the sample may be impossible to assess. The production of spectral data, using quantitative fluorescence microscopy, has proved to be one method of characterising amorphous organic matter (AOM), if the fluorescence measured is due predominantly to one type of material; but the spectra produced by this technique can be inconclusive if the fluorescence is due to a mixture of several different types of organic material. Mathematical manipulation of the raw spectral data can be performed on complex spectra. Fourier self-deconvolution, described in this paper, has proved successful in the identification of more than one type of organic material from an amorphous spectral distribution.