Siraj Beyan Mohammed

Addis Ababa Science and Technology University, Ethiopia

Title: Genesis and Styles of Akobo Gold Mineralization within the Surma Shear Zone ultramafic belt in Southwestern Ethiopia

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Biography

Abstract

The Genesis and Styles of Akobo Gold Mineralization refers to the intricate geological and mineralization processes that characterize gold deposits within the Surma Shear Zone ultramafic belt in southwestern Ethiopia. This region, particularly the Segele gold deposit, is notable for its complex geological history marked by tectonic evolution, hydrothermal alterations, and diverse mineralization styles, which have drawn significant interest for exploration and mining activities in recent years. The Segele gold deposit, located in Southwestern Ethiopia, is a significant ultramafic-hosted mineral resource that has garnered attention for its geological uniqueness and economic potential. Situated within the Neoproterozoic Arabian-Nubian Shield, the deposit is characterized by a complex interplay of ultramafic and mafic volcanic sequences, where gold mineralization is primarily associated with ultramafic rocks little bit affected by hydrothermal processes. The exploration of the Segele deposit has revealed an indicated and inferred resource of approximately 94 tonnes, containing 69,000 ounces of gold, with an exceptional grade of 40.6 g/t in the indicated portion . The genesis of the Segele gold deposit is rooted in a series of intricate geological and geochemical processes, particularly the metamorphic alterations and the structural controls that favor gold concentration in pyrocinite and carbonate veins. The deposit's formation is closely linked to tectonic activities associated with the major shear zone associated with Najd Fault System, which facilitated the movement of mineralizing fluids through fractures in the crust, allowing for the accumulation of gold and other base metals. The area's rich mineralization also reflects broader hydrothermal activity, suggesting that extensive geological forces have shaped the region over millions of years. The gold deposits are primarily classified as Orogenic Gold Deposits, formed in association with extensive tectonic activities that led to the formation of distinct mineral assemblages ultrawithinplay of geological, hydrothermal, and tectonic processes that govern gold deposition. Hydrothermal fluids rich in gold are believed to be transported in solution and precipitated under varying physicochemical conditions, which include temperature, pressure, and fluid composition changes. The presence of arsenopyrite and other sulfide minerals plays a critical role in the concentration and deposition of gold, facilitating the development of significant ore deposits in the region. Various styles of gold mineralization have been identified within the Akobo region, including faulthosted  quartz-vein systems, orogenic deposits, and Carlin-type mineralization. Each style exhibits distinct geological and hydrothermal characteristics, influenced by local structural controls and alteration processes. This diversity not only reflects the complexity of mineralization in the Surma Shear Zone but also underscores the potential for future discoveries and resource development in the area.