During the IGCP616Y,the first young project lead by central African Scentist, a database has been built for major tectonic boundaries in central Africa (Kankeu et al. 2012; Danguene et al.2014). scientific activities resulted in the proposition of a new tectonic model for the frontal part of the Pan-African Central Africa Fold Belt against the older cratonic basement of the Congo craton ( Kankeu et al . submited). We have documented at the scale of the southern margin of the Pan-African Central Africa Fold Beld (CAFB) towards the northern margin of the Archean Congo Craton (CC), the spatial association of km-scale strike-slip shear zone and compressional structures such as thrust, folds and foliations which point to a complex
transpressional tectonic evolution perhaps involving zones of pull-apart which allowed the ascent of the magma/granitoides.
Further work is need to show the southward continuation of these shear zones and tectonic boundary , their regional significance into an original Gondwana context and establish genetic links between the geodynamic processes that form the belt and primary ore controls and processes of ore formation. Apart from the importance for the Pan-African evolution, these structures are inferred to have influenced the subsequent tectonic evolution.
Evolution of Mesozoic-Cenozoic fault bounded sedimentary basins and Cenozoic magmatic activity
Mesozoic-Cenozoic fault bounded sedimentary basins of Central Africa Rifts System (CARS) are more or less rich in oil and gaze resources which Izuchukwu Mike (2013) related to stratigraphic ( slope channel fills, mature surfaces, lithologic wedges, basin floor fan and pitchouts) and structural ( hanging wall, footwall closures, half grabens ) traps. Theirs location, type and evolution have been controlled by tectonics activity accompaning the rifting and separation of West Africa from Brazil and the opening of the Atlantic ocean during Cretaceous. Further work is need to documented continuous tectonics activity accompaning the rifting and better integrate onshore and offshore geology on both sides of the Atlantic. Within plate Cenozoic magmatic activity along the Cameroon Volcanic Line (CVL) is also largely determined by the reactivation of early formed lithospheric structures. The CVL is doted with numerous cinder cones and crater many of which are occupied by lakes found to contain very high accumulation of volcanic gases principally carbon dioxide. Two of these lakes (Nyos and Monoun) have been sites of toxic gases indicating that crater lakes of CVL are dangerous and constitute risks of futures gas emission. Although pre-existing faults and shear zones represent a mechanical weakness both at upper and lower crustal evels, not all fault and shear zones reactivate or have any apparent influence on latter structural development. When deep Precambrian structures do reactivate, the maner of the reactivation and its precise influence on later structural evelopment is often poorly defined.
Neotectonic, paleoclimate ans landscape evolution
More recent earthquakes in west and central Africa appear to be spatially related to the preexisting Pan-African shear zones hich may thus be in a state of continuing-reactivation and therefore, zones of potentially high geological risk both for people and for infrastructure. Interacting elements of several different driving mechanisms operating at different spatial scales may produce localized uplift, as well as regional mantle-scale mechanisms producing more regional uplift. Pre-existing aults and structures in the region, seen to have been reactivated in the more recent geological past and present tectonic readjustment are revealed by present seismicity of certain regions ( Nnange 2008); It is suggested ( Runge et al. 2008) that reactivation of pre-existent fault structures may have play (assisted by climate fluctuation?) and important role in the development of the today stepped to staircase-like topography of planation levels. Differential vertical movement at both regional and local scale may have resulted in landscape instability and rapid geomorphic evolution. This is associated with significant changes in tectonic topography and, landscape evolution .Unfortunately the interrelationship of basement structures, neotectonics, paleoclimatology and landscape evolution still somewhat ambiguous. Weathering over long periods of time results in thick commonly lateritic blanket in tropical region with almost complete alteration of the mineralogical, chemical and pretrographic characteristic of bedrock hosted mineralization, presenting particular challenges in exploration. However, the geochemical dispersion of ore-related elements can create larger, though commonly subtitle, exploration targets. A sound understanding of the evolution of the landscapes in which they occur appears to be the best ways through which these can be tackled.
Climate fluctuation/change, weathering depths and people adaptation.
There is also widespread evidence and recognition that fluctuations in climate affected regional environments in central Africa by modified rainfall and hydrological characteristics resulting in heavy rainfall, landslide, flood and drought, aggravated by urban development, roads and agricultural activities including livestock and farming up the hills .Poorest people’s living in these regions with limited potentials for adaptation are directly affected by climate hazards and are usually unable to deal with them unaided. Degree and extend of regional or local climate fluctuation/change and its influence on weathering depths and decomposition of rocks, option available to population remain poorly know. Both economically as well as for the large scientific and public community the long and short-term dynamic interaction between basements studies, active tectonic , climate change, landscape evolution and sustainable management of scarce natural resources like water and soil remain poorly know in west and central Africa as they might be in other parts of the world.