Compositional Analysis and Morphological Relationships of Amphiboles, Talc and Other Minerals Found in the Talc Deposits from the Gouverneur Mining District, New York (Part 2 of 2)
THE MICROSCOPE
2014, Volume 62:1, pp. 3–13
DOI
https://doi.org/10.59082/DBQK4098
AUTHORS
Brittani D. McNamee and Mickey E. Gunter
ABSTRACT
The authors characterized the chemical composition and morphology of minerals in rock samples and processed products from two former talc mines owned by the R.T. Vanderbilt Company (RTV) in the Gouverneur Mining District in New York State. The main mineral phases within these samples are tremolite, anthophyllite and talc with serpentine, quartz, calcite, and diopside. Bulk analyses of the samples were performed by powder X-ray diffraction (XRD) for structural phases and by X-ray fluorescence (XRF) for bulk chemical composition. Precise compositional data of individual grains were collected by wavelength dispersive spectroscopy (WDS) using an electron microprobe. Mineral formulas were calculated from the resulting weight percent oxides. The morphology of the different mineral phases was observed with backscatter electron (BSE) images and polarized light microscopy (PLM).
All of the mineral phases analyzed have near endmember compositions. The compositions and morphology of the minerals do not vary significantly between the two mines. Tremolite occurs in the samples mainly as unaltered, blocky crystals. Anthophyllite mainly occurs with an acicular texture and a series of fractures perpendicular to the long axis of the crystal. Talc occurs both as platy crystals and as fine-grained asbestiform particles as alteration products of primarily anthophyllite, which occurs in a non-asbestiform habit.
This is the second part of a two-part paper. The first part appeared in Vol. 61, No. 4 (2013).