Spectral reflectance in the visible and near infrared portion of the spectrum (0.35 to 2.55 μm) offers a rapid, inexpensive, non-destructive technique for determining mineralogy and providing some information on the minor element chemistry of the hard-to-discriminate carbonate minerals. It can, in one step, provide information previously obtainable only by the combined application of two or more techniques, and can provide a useful complement to existing mineralogical and petrographic methods for study of carbonates. Calcite, aragonite, and dolomite all have at least 7 absorption features in the 1.60 to 2.55 μm region due to vibrational processes of the carbonate ion. Positions and widths of these bands are diagnostic of mineralogy and can be used to identify these three common minerals even when an absorption band due to small amounts of water present in fluid inclusions masks features near 1.9 μm. Broad double bands near 1.2 μm in calcite and dolomite spectra indicate the presence of Fe2+. The shapes and positions of these bands, if present, can aid in identification of calcites and dolomites. Spectra may be obtained from samples in any form, including powders, sands, and broken, sawed, or polished rock surfaces.

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