# Characterization of talc deposits in ultramafic rocks of Gebel El Maiyit and its economic feasibility

## TL;DR

This study examines talc deposits in Gebel El-Maiyit, Egypt, to determine their composition and economic potential.

## Contribution

The paper introduces a detailed characterization of talc types and their formation conditions, along with economic feasibility insights.

## Key findings

- Three talc types were identified: pure talc, tremolite talc, and chlorite talc.
- Talc deposits formed at low temperatures (around 100°C) and higher temperatures (140–175°C) for magnesite.
- High iron and manganese levels require treatment for electrical insulation use, but arsenic levels are low enough for cosmetic applications.

## Abstract

A comprehensive, multiscale investigation, integrating remote sensing, mineralogy, whole rock chemistry, Electron Microprobe (EMP), and stable isotopes (oxygen-18O and carbon-13C), was undertaken to assess the feasibility of talc deposits and their host serpentinite at Gebel El-Maiyit in the Eastern Desert of Egypt. Sentinel 2 remote sensing images were applied to discriminate talc from serpentinites followed by geochemical study of serpentinites using RO`/SiO2 ratios, AFM diagram and MgO versus SiO2 relationship indicates a peridotite origin formed at low temperature Alpine type. Our study revealed that talc deposit has a varied mineralogical composition and according to the predominant talc and gangue minerals three main types have been distinguished: 1- pure talc, 2- tremolite talc and 3- chlorite talc. Paragenetically, talc is derived from serpentine minerals, tremolite and chlorite. The latter is formed at about 231 °C. The chemical data of talc deposit reveals that the summation of talc components (SiO2 + MgO + H2O) is 92.68%, while that of impurity oxides (Al2O3 + CaO + Fe2O3 + FeO) is 5.56%. The carbon13C) and oxygen18O) contents of pure magnesite revealed that the pure phase of Gebel El-Maiyit was formed at low temperature (around 100 °C) while magnesite contained in talc carbonate rock was formed at high temperature (140–175 °C). In terms of source fluids, the metamorphic and /or magmatic water was supposed to be the main fluids which are circulated during the hydrothermal alteration. Although S and P are very minor components in all the talc ore types of the considered area and do not affect their industrial use. Copper (Cu) was not detected. Iron (Fe) and manganese (Mn) concentrations are significantly high, necessitating treatment to reduce these elements for the ore to be suitable as an electrical insulator. Arsenic (As) levels are consistently below 5 ppm, indicating the ore’s potential use in the cosmetic industry without further processing.