Rapid Analysis of Muscovites on a Lithium Pegmatite Prospect by Handheld LIBS

June 22, 2023

May 19, 2023

Publication: Russell S. Harmon, Michael A. Wise, Adam C. Curry, Joshua S. Mistele, Michael S. Mason, and Zach Grimac. “Rapid Analysis of Muscovites on a Lithium Pegmatite Prospect by Handheld LIBS,” Minerals 2023,13, 697.

Representative LIBS spectra for a CLP muscovite sample showing emission lines for the elements of interest to this study (red arrows, brackets, and text), the Ar peaks in the infrared portion of the spectrum between 700 and 870 from the Ar purge gas used for the analysis (grey brackets and text), and other elements (black arrows and text).

Abstract: Laser-induced breakdown spectroscopy (LIBS)is a technology for compositional analysis that is particularly effective for light elements, particularly Li, which is a critical commodity for emerging green technologies. This study undertook analysis by handheld LIBS of muscovite from the drill core, outcrop, and soil on the Carolina Lithium Prospect (CLP)in Gaston County, North Carolina (USA), which lies within the Carolina Tin-Spodumene Belt (CTSB). Abundances of the alkali elements Li, K, and Rb were determined for more than 130 muscovites from the Li-rich pegmatites to track the degree of pegmatite fractionation as a pathfinder for spodumene mineralization. Across the CTSB and including the CLP, muscovite Li contents vary over an order of magnitude, ranging from 0.04 to 0.74 wt. %, with their K/Rb ratios varying between 63 and 8, features that together document the highly evolved character of pegmatites within the CTSB district. On average, muscovite Li contents are greater in spodumene-bearing pegmatites at 0.21 ±0.12 wt. % than for common quartz-feldspar pegmatites at 0.14 ± 0.08 wt. %.Although overlapping substantially in the middle portions of their distributions, muscovite K/Rb ratios are biased toward low values for spodumene-bearing pegmatites (X = 21 ± 6) compared to those for quartz-feldspar pegmatites (X = 33 ± 9). This study provides a framework for the use of LIBS analysis of muscovite in outcrop, drill core, and soil samples as an analytical tool for in-field and on-site geochemical analysis during Li pegmatite exploration and prospect evaluation.

Access to publication: https://doi.org/10.3390/min13050697

About this journal: Minerals is an international, peer-reviewed, open access journal of natural mineral systems, mineral resources, mining, and mineral processing. Minerals is published monthly online by MDPI.

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Like its predecessor, the Z-300, but with updated form and software, SciAps Z-903 handheld analyzer measures every element in the periodic table of the elements – from H to U. The extended spectrometer range from 190 nm out to950 nm, allows measurement of longer wavelength emission lines from elements like H, F, N, O, Br, Cl, Rb, Cs and S to be measured. Other benefits include amore sensitive line for lithium near 675 nm to achieve limits of detection in the 2-5 ppm range and potassium without the interference of heavy iron. TheZ-903 is most widely used for mineral exploration, forensics, authentication, and archeology due to the wide elemental range.

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