Soft x-ray microscopy and microanalysis: Applications in organic geochemistry
- Argonne National Lab., IL (United States). Chemistry Div.
Soft X-ray imaging and C-NEXAFS microanalysis has 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 sp{sup 2} 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.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 220791
- Report Number(s):
- CONF-950793--; ISBN 0-8194-1875-7
- Country of Publication:
- United States
- Language:
- English
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