University of Twente Student Theses
The mineralogical and spectral characteristics of a lithium-bearing pegmatite system
Okeke, I.J. (2024) The mineralogical and spectral characteristics of a lithium-bearing pegmatite system.
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| Abstract: | Lithium-bearing pegmatite systems are significant sources of lithium, a critical element in modern energy storage technologies, particularly in the production of lithium-ion batteries. Despite their importance, these types of mineral deposits have been subjected to numerous studies over the years, using a variety of approaches. The analysis of the spectral characteristics can be used to identify the mineralogy with different alteration events associated with granitic intrusions hosting the deposit of lithium-bearing minerals. The occurrence of mineral commodities is usually attributed to geological events, which is why a mineral exploration strategy needs to be developed to identify and describe lithium-bearing pegmatite systems, especially in areas with little or no pegmatite exposure linked to early lithium exploration. Alterations such as metamorphism events can be observed in the visible-near infrared (VNIR) and short-wave infrared (SWIR) spectrum. This research combines laboratory measurements and airborne geophysical datasets to identify and describe a known lithium-bearing pegmatite system in Southwestern England. It aims to analyze the spectral characteristics and mineralogy using an integrated approach of SWIR imaging spectroscopy, VNIR-SWIR spectroscopy, portable X-ray Fluorescence (XRF), X-ray Diffraction (XRD), and magnetic susceptibility with airborne radiometric and magnetic datasets. The laboratory data has proven useful for identifying small features such as aluminous micas, tourmaline, biotite, and topaz in the granite and pegmatite samples while the airborne radiometric and magnetic data improve the identification and characterization of larger features such as granitic plutons. The wavelength maps in the SWIR range were used to identify and map the aluminous micas; muscovite, and illite using the shift in the Al-OH absorption characteristics to determine the spectral mineralogy which includes muscovite, illite, topaz, tourmaline, and biotite. VNIR-SWIR spectroscopy provided useful information, especially in the VNIR region of the spectrum, which allowed lithium-bearing micas like zinnwaldite and lepidolite to be identified. In this study, the stacked spectra of the samples obtained from each component, based on the type level, provided information about the trend in the fractionation process that led to the deposit of minerals. XRD analysis provided insight into the identification of minerals like quartz and feldspars and was compared with the results of the spectral analysis. The radiometric and magnetic signatures provided useful information for improving the characterization of the larger features in the lithium-bearing pegmatite system. The results from the spectral mineralogy and chemical variations showed the progressive fractionation and evolution of batholith granites, topaz granites, and aplite pegmatite from the parent magma. This study demonstrates that by integrating these diverse analytical methods a more robust identification and characterization can be achieved by addressing the limitations of individual methods. |
| Item Type: | Essay (Master) |
| Faculty: | ITC: Faculty of Geo-information Science and Earth Observation |
| Subject: | 38 earth sciences |
| Programme: | Geoinformation Science and Earth Observation MSc (75014) |
| Link to this item: | https://purl.utwente.nl/essays/102562 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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