Remote sensing applications for carbonatite assessment and mapping using VNIR and SWIR bands at Aluyaynah, UA E

This dissertation undertakes the experimental analysis of multispectral reflectance data to remotely differentiate and lithologically map the extrusive carbonatites from the adjoining rock units in the Al-Uyaynah region located within the northeastern terrain of UAE. The study employs visible/near-infrared (VNIR), shortwave-infrared (SWIR) spectral measurements developed in the laboratory using ASD, Landsat OLI, and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images of extrusive carbonatites in Al-Uyaynah metamorphic sole units. Chapter 1 of the study is a succinct overview of the entire effort. It also encompasses the context of remote sensing and the use of the reflected spectrum from visible to shortwave-infrared in mineral exploration. In particular I focus on carbonatite identification and analysis for the purpose of geological mapping. In Chapter 2 of this study, I perform tests and analyses on new Landsat 8 image data over Al-Uyaynah- UAE so as to examine the validitity of this system for medium resolution distantly sensed reflectance measurements. Specifically, I examine the utility of Landsat 8 imagery to define carbonatite outcrops and relevant lithological components. Chapter 3 of the study examines the Thermal Emission and Reflection Radiometer (ASTER) VNIR and SWIR data over the Al-Uyaynah region. In this Chapter I leveraged an existing low resolution geologic map, ASD laboratory measurements, and field data to examine the spatial distrubtion of carbonatites, alkali volcanics, metavolcanics, and an ophiolite complex using ASTER imagery. I further tested the efficency of four different mapping algorithms for their utility in effectively discriminating between the units and their locations. Chapter 4 of my dissertation examines the relationship between the composition and spectral charachteristics of carbonatite rocks. In this Chapter, carbonatite samples were examined spectrally within the visible near infrared (VNIR) and short wave infrared (SWIR) bands using a lab-based spectroradiometer device (ASD). The carbonatite rocks samples, were analyzed geochemically to determine the major oxides components in the weight percentage (wt%) using X-ray fluorescence (XRF). Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) techniques were then applied in order to determine the rare earth elements (REEs) concentrations in the carbonatites. The ASD spectra and the chemical analysis results offered us a deep understading of the connection between the rock composition and spectral behavior of Al-Uyaynah carbonatite rocks. In Chapter 5 of this study, the entire research effort is combined in a synthesis that links the outcomes from each chapter into a comprehensive study of the spectral characteristics of carbonatites from the Al-Uyaynah region. Pathways for further of research are also recommended. This investigation is significant as it presents: (1) New ways of employing multispectral systems, Landsat 8 and ASTER, for use in the geological mapping of carbonatites; (2) Methods to recognize the mineralogical indicators for ferro/calcio-carbonatites; (3) evalutions of mapping algorithms and creates rankings based on their precision and accuracy for utilization in complex metamorphosed geologic terraines.