Geology and geotectonic classification of pan-african gold mineralizations in the red sea hills, sudan

Hundreds of ancient gold mines and prospects are known in the Red Sea Hills of the Sudan, and many are still of economic importance. Most of the mines are part of the Pan-African tectonostratigraphic sequence. The genesis of the gold expresses three geotectonic events that have left their marks on the style of the mineralization. The first type (I) is syngenetic with volcanogenic massive sulfide deposits that are associated with calc-alkaline, island-arc, acidic volcanism, where gold was deposited some 715 Ma ago. The second type (II) is related to a major tectonic-metamorphic episode during collisional orogeny, which caused the remobilization of gold and its precipitation in silica-barite and massive barite formations, possibly around 650 Ma. The third type (III) takes the form of auriferous quartz veins along first- and second-order shear zones related to postcollisional movement and retromorphism, at ∼550 Ma. Gold was remobilized from volcano-magmatic sequences to be precipitated along structurally more favorable sites.