Mineralization of the In Ateï gold district (Central Hoggar, South Algeria)

The In Ateï gold district is located in the eastern part of the Laouni “LATEA” terrane (acronym of Laouni, Azrou-n-Fad, Tefedeset, Egéré-Aleksod) (central Hoggar, southern Algeria). In fact, during the post-collision period of the Pan-African orogeny (600 and 570 Ma), this microcontinent was partly destabilized until it corresponded to a meta-craton. The In Abeggui gold deposit is part of the In Ateï district and is located 210 km southeast of the town of Tamanrasset. It is located in a large gabbro-diorite massif of the Neoproterozoic volcano-sedimentary series. The In Abeggui deposit shows two morphological types of gold veins and a mineral paragenesis different from the rest of the Hoggar. In the In Abeggui deposit, a biotite granite pluton comprising contemporary gabbro-diorite bodies is intrusive in the Neoproterozoic volcano-sedimentary series. The mineralized veins are mainly hosted in one of these mafic bodies. Numerous dykes of mafic and felsic rocks cut both the biotite granite and the gabbro-diorite massif. Felsic dikes include granites, microgranites, pink aplo-pegmatites and aplites. The main objective of this work is to study the types of gold mineralization expressed in the Laouni terrane (central Hoggar) based more particularly on those of the In Atei region. Two generations of gold-bearing quartz from the In Abeggui deposit can be distinguished: Veins 1: Tourmaline quartz veins predominantly N30° embedded in the gabbro massif, and Veins 2: Stockwork and quartz veinlets, hosted in aplite dykes covering the vein system1