Soft x-ray microscopy and microanalysis: applications in organic geochemistry

George D. Cody; Robert E. Botto; Harald Ade; Sue Wirick

doi:10.1117/12.221673

25 September 1995 Soft x-ray microscopy and microanalysis: applications in organic geochemistry

George D. Cody, Robert E. Botto, Harald Ade, Sue Wirick

Proceedings Volume 2516, X-Ray Microbeam Technology and Applications; (1995) https://doi.org/10.1117/12.221673
Event: SPIE's 1995 International Symposium on Optical Science, Engineering, and Instrumentation, 1995, San Diego, CA, United States

Abstract

Soft x-ray imaging and C-NEXAFS microanalysis have been used to analyze the organic geochemistry of bio/geo-macromolecules (sporopollenin) in-situ and in a rank variable suite of organic rich sediments extending from recent up to the equivalent of medium volatile bituminous rank. The acquisition of images with the monochromator tuned to 285.5 eV, corresponding to the 1s - (pi) ^* transition of unsaturated carbon, reveals a homogeneous chemical structure in the spore outer wall (exine). Across the rank range absorption at 288.1 eV, corresponding to the 1s - 3p/(sigma) ^* transition of aliphatic carbon, matches that of the surrounding, matrix, vitrinite suggesting that the aliphatic carbon within the two macerals undergoes a parallel chemical structural evolution over the rank interval analyzed. Carbon near edge absorption fine structure spectroscopic microanalysis reveals clear trends in the chemistry of sporopollenin/sporinite. The most pronounced being an increase in the concentration of sp² hybridized carbon. The rate of increase exceeds that of similar aromatization trends in the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and alkyl carbon bonded to oxygen. The concentration of COOH,R groups is low and does not change across the rank range analyzed.

Citation Download Citation

George D. Cody, Robert E. Botto, Harald Ade, and Sue Wirick "Soft x-ray microscopy and microanalysis: applications in organic geochemistry", Proc. SPIE 2516, X-Ray Microbeam Technology and Applications, (25 September 1995); https://doi.org/10.1117/12.221673

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