Raman spectral shifts in naturally faulted rocks

D. K. Muirhead* (Corresponding Author), L. Kedar, A. Schito, S. Corrado, C. E. Bond, C. Romano

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)
2 Downloads (Pure)

Abstract

AbstractRaman spectral shifts of carbonaceous materials arising from faulted rocks produce varied and complex results. By analysing faulted and adjacent non-faulted samples from four discrete localities in France, Italy and Morocco, we assess changes in specific Raman parameters, including G-peak width, G-peak position, and peak intensity ratios. We consistently observe a shift in Raman parameters between faulted and non-faulted samples; however, the direction and magnitude of this shift varies. Raman peak intensity ratios are shown to both increase and decrease on fault planes. The majority of samples exhibit decreasing peak width and peak position in the faulted samples, but this is not consistent; in two samples an increase is observed, but the shift tends to be small. These data are compared to published Raman spectral shifts from experimental fault data. Our results suggest that fault zone deformation processes may measurably change the carbon nanostructure in faulted rocks. The inconsistent nature of Raman spectral shifts in the fault rock samples analysed, and those published suggest that a complex set of factors control carbon nanostructure changes in fault rocks. These factors, although not discriminated here, likely include, background temperature, frictional heating, strain, carbonaceous material type, amongst others. We have shown that Raman Spectral shifts occur in faulted rocks with implications for how Raman data are used to predict maximum temperatures in faulted sedimentary rocks. We recognise the potential for a range of fault zone processes to modify Raman spectral shifts, however, systematic sampling across individual fault zones is critical.This article is protected by copyright. All rights reserved.
Original languageEnglish
Article numbere2021GC009923
Number of pages13
JournalGeochemistry, Geophysics, Geosystems
Volume22
Issue number10
Early online date20 Oct 2021
DOIs
Publication statusPublished - 20 Oct 2021

Bibliographical note

Acknowledgements.
We thank Colin Taylor at UoA for help in sample preparation.This study was supported by the School of Geosciences at the University of Aberdeen and in part by the NERC Centre for Doctoral Training in Oil & Gas (Grant Number: NE/R01051x/1).

Keywords

  • raman
  • carbon
  • faults

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