Abstract
The western part of the Lake Kivu has been described through geological campaign and hypothesis relative to origin, the nature of rocks and tectonic events have been discussed. Field investigation and outcrops description have revealed that Quartzite, Schist, Gneiss and Granite are the most spread rocks around the area. The research undertaken provides the structural analysis of rocks deformations in the surrounding mountains of the Nyamukubi area including structures such as lineaments, joints and faults were identified and their geometric measurement such as dip and rock direction were noted and the analysis on field were done using the stereographic projection Geological investigations suppose that Nyamukubi is built on abasement terrain made by Precambrian metamorphic rocks intruded by granites. It is a terrain whose Kibarian erogenous and the rifting events have completely transformed into folded and a faulted system. The structural analysis supposes that the Kibarian erogenous has transformed the geological material into folded and faultedand the rift event have completed by setting up a normal faulting morphology. Through the structural analysis, it was found that the Nyamukubi area has been deformed into folds and faults by a compressional NE-SW constraint. These compressional stresses might be originating from the Mesoproterozoic kibara erogenous whose results are till now observed through geological materials and forms. However, some extensional movement markers such as veins and normal faults were identified and described. The structural analysis of quartz veins supposes that they are the result of the post orogenic granites whose fluids filled the fractures left by the Kibarianerogenous; these are mineralization containers.
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