The study area is located in the southeastern part of the Comoé basin (southeast of Côte d’Ivoire, north of the town of Alépé). The geology of this study area is marked by granitoids (two-mica bearing granites, granodiorites, microgranites and pegmatites) and metamorphic rocks (gneiss, micaschists, metawackes and schists) which are crossed by several quartz veins. The aim of this study is to identify the petro-structural and metallogenic features of the quartz veins in this part of the Ivorian birimian. The methodology used focused on geological surveys, petrographic descriptions (macroscopic and microscopic), structural analysis and metallogenic analyzed. The petro-structural study revealed the presence of saccharoid quartz veins, tourmaline bearing quartz veins, banded tourmaline quartz veins, biotite bearing quartz vein, translucent quartz veins, smoky quartz veins, white to milky white quartz vein. The morphology of the veins is variable: rectilinear or fusiform with a main NE-SW orientation and secondary orientations NNW-SSE and E-W. In addition, these veins are generally deformed in the form of folds, tension slots, sigmoidal figures. These structures demonstrate the existence of shear corridors. The presence of rolling extinction and quartz subgrains were highlighted by microscopic observations, confirming the dislocation creep mechanism. This mechanism indicates high temperature and differential stress conditions. Observations with metallographic microscopes coupled with geochemical analysis data show that sulphides and gold are present in the fracture planes and quartz subgrains and generally associated with the quartz-tourmaline veins. Hence, the interest in taking into account the quartz-tourmaline association in gold prospecting in the Birimian rocks.

The Sassandra-Cavally (SASCA) domain (SW Côte d’Ivoire) marks the transition between the Archean Kenema-Man craton and the Paleoproterozoic Baoulé-Mossi domain. The methodology applied to study the rocks of the Soubré area considers both field and laboratory work. The Soubré area of the SASCA domain is characterized by migmatitic gneisses, metagranites and garnet micaschists. Migmatitic gneisses are composed of quartz, feldspar, biotite, chlorite, muscovite and opaque minerals, with occasional amphibole rods. Metgranites, on the other hand, are composed of quartz, feldspars such as plagioclase and microcline, biotite, accessory minerals and opaque minerals. Garnet-bearing micaschists are composed of quartz, biotite, muscovite, garnet, plagioclase with accessory and opaque minerals. Structural observations in the Soubré area reveal a first foliation (S1) trending NW-SE, dipping between 40° and 85° towards SW and associated with a N080-trending shear with a sinistral component, as well as folds whose axial planes are parallel to S1. This first foliation is intersected by a second (S2) trending NE-SW with dips of 60-85° either towards NW or SE. The S2 foliation is associated with a N166 shear with a sinistral component and folds whose axial planes are parallel to S2. All these structural observations in the Soubré sector would be compatible with the structures observed in the SASCA domain on the coast from Grand-Béréby to Tabou.