Orthogneiss occupy most of the western half of the site. Magnetite and/or BIF pyroxenites and quartzites are associated. These rocks are defined by foliation in the form of clear bands containing quartz-feldspar minerals and dark bands made of ferromagnesians (amphiboles-pyroxenes) (Figure 3). However, when poor in ferromagnesian minerals, foliation is expressed rather by an alternation of light bands with slight proportions of ferromagnesians that cannot consist of real dark bands. Orthogneiss sometimes contain fragments of mafic rocks

subparalled to foliation. Under the microscope, it has a granoblastic texture and the alternation of light and dark bands (foliation) is slightly more pronounced. We can also note the presence of quartz veins. The minerals clear as dark are difficult to identify except a few grains of quartz and biotite which are still large in places (Figure 4, Figure 5(A)).

Two traces of granitic rock, occupying the eastern half of the permit and separated by the Sassandra River, form this unit: granites and pegmatitic granites. The granites usually appear as domes in the Gbétéma and Ladjibougou sectors (Figure 5(B)). Granites have a massive appearance or have low deformation gradients (Figure 5(C)). They have a normal grainy texture and are formed of quartz minerals, feldspars, biotite and sericites (Figure 6). As for pegmatitic granites, they have a pegmatitic grainy texture marked by the presence of large quartz crystals (Figure 5(D)). To this is added the granodiorites whose outcrop was observed in the south in the sectors of Ladjibougou (Figure 7(A)). They contain enclaves of surrounding rocks (Figure 5(E)). Granodiorites also have a grainy texture and are composed in addition to the minerals already mentioned, amphiboles and pyroxenes (Figure 7). Microscopically, they are dominated by quartz (in phenocrysts in pegmatitic granites). In addition, microclines, sericites biotites, amphiboles, pyroxenes, plagioclases and garnet.

The quartzites form the large north-south mountain range that occupies the southwest of the permit. These quartzites appear under two facies: magnetite-poor facies and a magnetite-rich quartzite facies. Magnetite-poor quartzites: this facies is essentially composed of metamorphosed silice and feldsparths with very low magnetites, usually observed as porphyroblasts (Figure 8). Under the microscope, these quartzites have a granolepidoblastic texture. It is essentially composed of quartz. To this are added some minerals of sericites and magnetites (Figure 9). Magnetite-rich quartzites: these are quartzites containing high magnetite levels almost in the form of hematite. There are grey or dark brown hematite

beds, which alternate with red or orange silica beds to form BIF (Banded Iron Formation) or banded iron ore (Figure 10).

They have a granoblastic texture under the microscope. We also notice an alternation of band of hematites, ferromagnesian minerals (amphibole and pyroxene) and quartz (Figure 11) this Rock is rich in oxide including hematite which gives it the name of BIF.

Rocks occupy the central part following the North-South direction. The coiled and asymmetrical shape of this unit indicates that it has undergone non-coaxial

deformation. These volcano-sediments contain pyroclastic rocks and metasediments, usually intensely deformed and hydrothermally altered (Figure 12(A) and Figure 12(B)). Pyroclastites show a vacuolar texture, with carbonate porphyroblasts

(calcite). Those subject to alteration show carbonate departures, leaving empty hollows in the rock. Apart from carbonation, silicification and pyritization are also noted. Volcano sediments are sometimes marked by flux schistosity or are altered into sericitoschists (Figure 12(C)). Under the microscope, they have a granolepidoblastic texture and are composed of quartz, plagioclases, sericites, epidote, microclines and some biotites. There are also opaque minerals (Figure 13).

This unit contains on the one hand pyroxenites and on the other hand amphibolites. These are formations with limited contours or extensions that appear as intrusive in the western and southern parts of the permit. The pyroxenites, of gray-greenish color, show a foliated structure with a dominance of the dark bands rich in amphibole pyroxenes on the light bands mainly composed of quartz-feldspar (Figure 14(A)). They also contain garnet minerals of millimetre to centimetre size (Figure 14(B)). They outcrop to the North and South of the great chain of hills and constitute with the orthogneiss the encaissantes of the BIF. Amphibolites on the other hand show an aspect similar to the equante structure (Figure 14(C) and Figure 14(D)). They consist mainly of amphiboles (green hornblende) and plagioclase feldspars. Flush south of the permit in the Gbétéma and Sorotona sectors, they seem more or less associated with granites. Under the microscope, they have a granoblastic and sometimes granolepidoblastic texture. They are composed of pyroxene amphiboles, quartz, plagioclases, epidote, microcline, garnet and opaque minerals (Figure 15). We also observe some amphiboles from the hydration of pyroxene.

The microgranite veins associated with orthogneiss and pegmatite veins described in pegmatitic granites constitute the filonian unit (Figure 16(A) and Figure 16(B)). The microgranites, of decimetric to metric size and formed of quartz, feldspars and biotite, intersect in almost E-W direction (N110, 90˚S) the foliation. The pegmatites appear impressively in the village of Ladjibougou. They are formed by large quartz crystals, feldspars (orthosis) and biotite. However,

their overall pinkish coloration is probably related to the presence of orthosis in significant proportions.

S0 stratification was observed only in quartzites. It is more or less clear than in magnetite-poor quartzites (Figure 17(A)). It is oriented (N20, 80˚W). In magnetite-rich BIF or quartzites, it is confused with alternating beds of dark grey or brown hematite and silica beds (Figure 17(B) and Figure 17(C)). Tectonised, the beds are subparalled to S1 schistosity and have a strong dip to the west or are subvertical (80˚ - 90˚).

Schistosity is generally associated with magnetite quartzites, volcanosediments and amphibolitic schists. Magnetite quartzites are dominated by disjunct schistosity at a low angle of 10˚ - 15˚ with stratification (Figure 18(A)). It is orientation (N00-10, 80˚W). However, in BIF, stratification and schistosity give way to alternating dark and light beds rich respectively in magnetite (hematite) and silica (Figure 18(B) and Figure 18(C)). This S0-S1 structure shows variable orientations from north-south to north-west (N140, 80˚NE). The schistosity is also well visible in the volcanosediments and orientation (N180, 70˚W) (Figure 11(B) and Figure 11(C)). The schistosities associated with magnetite quartzite

formations or BIF and volcano-sediments are due to the establishment of the Sassandra fault. On the other hand, the schistosities described in the amphibolitic schists could be linked to the Eburnean cycle.

It characterizes orthogneiss that occupy the entire western portion of the site and is manifested by alternating light and dark bands, the former being quartz-feldspars and biotite-amphibole. Foliation is also present in pyroxenites. It has an orientation that evolves from an NNE-SSW to NNW-SSE direction via the N-S direction, with strong or subvertical dips (Figure 14(A); Figure 19(A) and Figure 19(B); Figure 20(B) and Figure 20(D)).

Several shear corridors have been distinguished, the main one occupying the central part of the permit. It extends over 5 km and crosses the entire permit from South to North, moving respectively from N-S to NNW-SSE. Smaller shear corridors of NNE-SSW to NE-SW, NNW-SSE and ENE-WSW orientations were also distinguished (Figure 19(B) and Figure 19(C)). The different structural elements suggest that the main shear is senelar as are the NNW-SSE and ENE-WSW orientation shears, while those oriented NNE-SSW to NE-SW are dextrous. Among these structures, we can distinguish isoclinal folds, shear bands, C/S factories, drive folds, microplis or crenulations (very marked in BIF), winding figures, intrafoliar folds, sheath folds, foliation or schistositydefelections, sulking, etc. (Figure 19). Mylonites or cataclases are associated with different shear zones; their characteristics vary according to the petrographic nature of the protolith. Protomylonites and mylonites are distinguished from orthogneiss and pegmatitic granites (Figure 21).

Faults and diaclases, joints and fractures are the elements of brittle deformation that have been highlighted. These structures are generally associated with shear zones. However, there are late fractures that cross all lithologies and structures. Overall, they are oriented NW-SE, N-S and ENE-WSW (Figure 22); however, NE-SW fractures were rarely observed.

Some fractures or joints filled with quartz form veins. However, quartz veins were rarely observed on this permit. Those observed are centimetric in size and generally oriented N-S to NNW-SSE and NE-SW (Figure 23(A)). The veins N-S to NNW-SSE are the most abundant. There are shear- or foliation-sub-allel veins, extension veins and tension veins (Figure 23(C), Figure 23(D), Figure 20(A)).