Structural Relationship between Brittle Deformation and Paleozoic to Mesozoic Basalt Dykes in the Precambrian Basement of the Southern Continental Part of the Cameroon Volcanic Line

Abstract

The work is a vivid description of the structural relationship between brittle deformation of the Precambrian basement in the southern continental part of the Cameroon Line and intrusive Paleozoic and Mesozoic basalt dykes swarms. A multidisciplinary approach that involves a combination of remote sensing techniques and field studies show that the major trend of brittle structures correspond to well-known regional structures: N70˚E (Adamawa Shear Zone), N135˚E (upper Benue trend) and N30˚E (Cameroon Volcanic Line) corresponding to E-W and N-S directions respectively. Basalt dykes are associated to NE-SW, E-W and NW-SE oriented fractures. An integration of the available information on brittle structures and basalt dykes directions suggest an emplacement of the Mesozoic and Paleozoic basalt dykes structurally controlled by Precambrian structures that were originated through Riedel's fracture kinematic model with dextral strike-slip Adamawa Shear Zone as the main shear zone during late stage of the Pan-African collision. Spatially, the restriction of the basalt dykes to the corridor of the Adamawa Shear Zone indicate that a rejuvenation of Precambrian faults may very well be the origin of the dykes with possibility that they may have been reworked several times during the Phanerozoic eon.

Assessment of Hydraulic Parameters and Protection Zones of Catchment Aquifers for Water Supply Network in Ndé Division, West-Cameroon (Central Africa)

“…It consists of variably deformed 580 Ma post-collisional, metaluminous to peraluminous, high K calc-alkaline to shoshonite affinity I type granitoids [16], originated from the partial melting of metasomatized sub continental lithospheric mantle with little crustal contamination and emplaced at the waning stage of the Central Africa Fold Belt in the 635 -645 Ma (U-Pb age, [17]), metagranodiorites and metaleucogranites associated to migmatitic gneiss. In the study area, these pan-African rocks are cross cut by cretaceous tholeiitic basalts [18] whose emplacement into in the upper crust was controlled by Riedel's fracture kinematic model [19]. These pan-African rocks are partially covered by tertiary basalts that formed the eastern edge of the western Cameroon Highlands located in the NE trending southern continental segment of the CVL that stretches from the Annobon Island to Lake Chad [20].…”