Investigation of the Chemical Causes of Variations in the Infrared Reflectance Spectrum of Chert

In this project, differences in the reflectance infrared spectra of chert from ten different localities are investigated using reflectance infrared microspectroscopy (RIRMS). Several other techniques including X-ray diffraction, petrographic analysis, energy dispersive X-ray analysis, and transmission infrared spectroscopy, were used to assist in the identification of trace minerals existing in each chert. Spectral manipulation (including subtraction and differentiation) appear to allow the identification of trace minerals in the chert reflectance infrared spectra. Two statistical analyses (correlation and a ratio analysis) were used to evaluate whether RIRMS could discriminate between visually similar chert types and to determine the extent of intrasample variation. Results of spectral manipulation and the statistical analyses indicate that RIRMS deserves further investigation into its applicability as a chert sourcing technique. Reflectance infrared microspectroscopy is an attractive potential sourcing technique because of its cost efficiency, reproducibility, ability to analyze for intrasample variation, and nondestructive nature