Raman Spectral Studies of Sedimentary Organic Matter

Organic matter of metasediments from Shixia,Longshui of South China and New Caledonia. has been studied by laser Raman microprobe. In all cases the Raman spectrum of two main bands at 1600cm^-1 and 1350cm^-1 having a bandwidth at half peak intersity respectively in the range 30 - 80 and 30 - 250cm^-1 depending on thermal maturity. The spectra are similar to anthracite coals and heat treated industrial carbons. Three distinct types of organic matter originating in sapropelic kerogen can be recognized in the carbonaceous slates of Longshui; (a) indigenous. (b) hydrothermal metamorphis, (c) migration bitumen. There are differences on the intensities,positions and widthes of the Raman bands characteristic of these types of organic matter. Indigenous organic matter of a suite of metasediments from New Caledonia was examined to mdetermine changes in the Raman spectra with thermal maturity. As the reflectance of the canbon increases from R°max (%) = 2. 10 to 14. 9, the width of the 1350cm^-1 Raman band decreases from 200 to 30 cm² At the same time, the and separation deceases form 255 to 230cm^-1, with increasing reflectance.while the ratio of band areas increases from 0. 38 to 1. 0.