A regional cartographic and tectonic study provided us with valuable information on the geological processes that shaped this region and its structural characteristics. This study allowed us to better understand the regional tectonics and briefly describe the geological history of the region and the formation of the main geological units. Geological mapping: Produce a detailed geological map of the rock formations of the region, including major geological units, faults, folds, lithological contacts and geological structures (faults, folds and deformation zones). The processing of the structural data highlighted the fact that the area was affected by several phases of deformation or orogeny. It is a polyphase zone. Statistical analysis with representation of the fracture distribution confirms the presence of three major peaks. This provides irrefutable proof that the area was affected by: - A family of submeridian breaks including NNW-SSE directed breaks. - An ENE-WSW fracture family. - And another fracture family orthogonal to the previous one, directed WNW-SE. The tectonic regime index (R’) values of 2.62 and 2 confirm that the study area was subjected to two types of regimes: the compressive regime and the shear regime. Using Win Tensor software, we understood that from a tectonic point of view, the area is polyphase, and the analysis with distribution representation highlighted the presence of three major peaks, confirming the presence of three fracture families: the NNW-SSE fracture family, the ENE-WSW fracture family, and the WNW-ESE fracture family. Based on the different results obtained from R’, the index of the tectonic regime (rotational optimization of stress tensor and PBT axes), two types of tectonic regimes are derived, namely a compressive regime with R’ = 2.62 and a shear regime with R’ = 2.
The formations of this region are essentially metamorphic Granit-Gneissic of which the term granitic is descended of the granitization-migmatization of Kimezien. Two tectonic periods have been demonstrated by double schistosities noticed to the level of the micas. The geochronology of these formations will be able to bring more precision on the age of these formations and that has the end will confirm or will invalidate the thesis to evoke in this survey.
This cartographic survey has been done from the samples of cores of polls achieved on longitudinal and transverse profiles as well as by the modelling, appropriated precisely in the concession of the mining of Bakwanga on the massif 12.
Of these data of polls, we could achieve a cartographic survey and deduct the structure of this massive kimberlitic under survey.
Let’s note that most polls on this massif, met the sand, sandstone, the epiclastic kimberlite, the xenokimberlite, the massive kimberlite and the limestone.
In a general manner, to part the limestone, the dolomite, sandstone and the sand, three facies kimberlitics has been put in evidence in this publication and it, according to the percentage in kimberlitics elements, it is about of:
- The kimberlite very tender epiclastic (0-25% of kimberlitic elements).
- The little strengthened xenokimberlite (25-50% of kimberlitic elements).
- The massive kimberlite (beyond 75% of kimberlitic elements).