GEOSOURCING TALC AND TALC ORES: ACADEMIC AND INDUSTRIAL APPLICATIONS

We are working on a long-term project obtaining talc, talc ores, and talc products and then fully characterizing them with a suite of analytical methods. The end goal of this project will be to determine the source (i.e., geological deposit or mine) of individual talc particles or talc ores. Part of this project works from first principals of talc formation and the resulting differing mineral compositions based on the talc being carbonate or ultramafic hosted. Secondly differing metamorphic conditions (either pro- or retrograde) will also results in different mineral assemblages.

Mineralogical characterization proceeds from bulk methods such as X-ray fluorescence (XRF) and powder X-ray diffraction (XRD), which would yield the overall composition of the material and mineral present to smaller and smaller scales. Electron probe microanalyzer (EPMA) is used in conjunction with wavelength dispersive spectroscopy (WDS) to provide accurate and precise compositions of individual mineral particles. Morphological analyses will be performed both with polarized light microscopy (PLM) at the larger scales and with a backscatter electron detector (BSE) mounted on the EPMA which also is equipped with a field emission gun for greater image resolution. And the PLM equipped with a spindle stage will be used to optical characterized the mineral particles. Other analytical methods such as Raman, Infrared, and Mössbauer spectroscopy will be used as needed to fully character the particles.

One example of integrating different methods would be if amphiboles are found in a product, and the amphiboles are near end-member tremolite as compared to Na and K rich. This would indicate different geological deposits. The same would be true for near Fe-free talc particles vs Fe-containing ones.