Gold mineralisation in the Haya Terrane, Northeast Sudan: combination of neoproterozoic host lithologies and shear zone controls

Gold exploration and mining activities in the Haya Terrane (HT) of Northeastern Sudan are primarily conducted by artisanal and small-scale operators, who often do so with minimal consideration for structural and geological factors. This lack of guidance results in inefficient resource targeting. This study seeks to delineate the structural architecture and lithological controls that influence orogenic gold mineralisation in the Halak area. The objective is to enhance predictive exploration models and to provide a framework for systematic resource development. The investigation involved comprehensive geological and structural mapping, petrographic analysis and geochemical assessment. The outcomes present four deformational phases, offering insights into the geological evolution of the area, which is intricately linked to the tectonic evolution of the Arabian-Nubian shield (ANS). During the initial deformational phase (D 1 ), schistosity surface (S 1 ) developed in conjunction with F 1 isoclinal folds, which exhibit a northeastward dip. The subsequent deformational phase (D 2 ) resulted in the formation of recumbent folds F 2 , characterised by NW-oriented axial planes and S 2 crenulation foliation. In the third deformational phase (D 3 ), earlier structures underwent refolding. Notably, the fourth deformational phase (D 4 ), associated with a dextral shear zone, is predominantly responsible for gold emplacement in the HT. The sericite schist is the predominant host rock, with its auriferous quartz veins attributed to the shear zone. Validation through chip, chip channel and drill samples have confirmed high concentrations of gold in regions displaying hydrothermal alterations with a mean value of 2 ppm. This study emphasises the significant role of structural deformation and shear zones in the localisation of orogenic gold deposits within the HT. Furthermore, it offers an enhanced framework for the exploration of gold mineralisation within the ANS.