New data on the identification of magnesium-rich carbonate phases using Fourier Transform Infrared Spectroscopy

This paper presents the theory behind the importance and applicability of Fourier infrared spectroscopy in identifying carbonate phases with varying magnesium content. It presents the results of studies of Triassic limestone and dolomite samples taken from the Polish part of the Germanic Basin, which were analysed using this method. The scientific significance of the FTIR method lies in its ability to identify carbonate phases with varying magnesium content, even at low levels. FTIR is one of the few methods that offer such possibilities.

The following phases were analysed: low-Mg calcite, high-Mg calcite, dolomite and huntite. These carbonate phases were identified based on wave numbers occurring in the infrared absorption spectra. Low-Mg calcite is the dominant phase in the limestones. Some samples also contain a small amount of high-Mg calcite. Dolomite and huntite were also identified. High-Mg calcite and dolomite are prevalent in dolomites and dolomitic limestones. The research results indicate that the rocks of the Gogolin Unit (Lower Muschelkalk) and Diplopor Unit (Middle Muschelkalk) exhibit the least differentiation in carbonate phase content with varying magnesium contents, whereas the rocks of the Tarnowice and Boruszowice Units (Upper Muschelkalk) exhibit the most. The results suggest that the rocks of the Lower Muschelkalk (Gogolin Unit) and Middle Muschelkalk (Diplopor Unit) are quartz- and kaolinite-rich limestones. In contrast, the rocks of the Upper Muschelkalk (Tarnowice and Boruszowice units) are dolomites and dolomitic limestones. The results of the study demonstrate that Fourier infrared spectroscopy is one of the most effective methods for identifying carbonate phases with varying magnesium content, including those with magnesium substitution, due to its ease of use and high level of accuracy.