Title: Origin of peridotites from Thurwah ophiolite (Saudi Arabia), and their potential for CO2 mineralization

Abstract : Mineral carbonation has been proposed as a cost-efficient and technically feasible alternative for permanent CO2 disposal. Peridotites have a significant prospect for in situ mineral carbonation due to the chemical potential and high reactivity of Ca-Mg-Fe-rich minerals with injected CO2-rich fluids to precipitate stable carbonates.

 In contrast to porous sedimentary rocks, crystalline rocks generally have low porosity and permeability. Therefore, In situ carbonation of the mafic and ultramafic rocks from the Jabal Thurwah complex strongly depends on the fractures network since this provides a powerful tool for predicting preferential fluid pathways and reactive surface areas.

The aim of this thesis is to evaluate the feasibility of carbon mineralization into the Jabal Thurwah complex by detailed petrological, mineralogical and geochemical analysis, including XRF, SEM-EDS, and whole rock geochemistry to evaluate the reactivity potential for i mineral carbonation.

 Furthermore, an extensive mapping of the spatial variation of the rock units, structural deformation styles and fracture distribution was characterized using aerial digital photogrammetry, field observations and Landsat images in order to calculate the available permeability in the complex.

 A thorough remapping of the Thurwah complex was conducted, focusing on the mantle sequence to confirm the origin of peridotites and evaluate the possibility of carbon mineralization by the carbifix process.

 Based on recent data on the chemical composition of olivine and Cr-spinel, it can be inferred that Jabal Thurwah represents a forearc-type ophiolitic mélange formed under conditions of high partial melting. Furthermore, this research presents the first discovery of rodingites, which provides additional evidence in favour of the occurrence of an ophiolitic mélange setting.