Textures in mylonitised granite from Banefo area in the central part of the Cameroon Central Shear Zone (central Africa) — Kinematics and gradian deformation indicators

The North Equatorial Panafrican belt is constituted by orthogneissified metamorphic and magmatic sets linked to tectonometamorphic events of the neoproterozoic orogeny. This belt whose formations are situated in the North of the congo craton is divided into three distinct geodynamic domains: a southern domain, a northern domain and a central domain. The deformation and metamorphism relationships are a function of the different geodynamic domains of the belt. The central domains, to which belongs the Banefo region, is affected by large strike-slip faults among which is the central cameroonian shear zone. This domain is marked out by numerous syntectonic granitoids. At Banefo (NE Bafoussam, West Cameroon), those massifs are mainly constituted by mylotinised orthogneisses and granites of various degrees. The country rock is made up of gneiss and amphibolite. In the Banefo massifs, the orthogneiss is the least deformed petrographic unit. It shows a heterogranular granoblastic texture with a mineral assemblage formed by quartz, K-feldspars, biotite, etc., within the orthogneiss, remains of magmatic fluidality can still be observed marked by feldspar megacrystal. Field observations reveal a net progression of the intensity of deformation of orthogeisses to ultramylotinised granites having an identical chemical composition as the orthogneisses...conferenc

A new practical and economical technique for the obtention of high quality thin section photographs with the help of a simple optical microscope

Microscopic study is an indispensable step in the determination of the petrographic characteristics of rocks. In Cameroon just like in most developing countries, simple polarizing microscopes of the 20th Century constitute the only available material for macroscopic studies. A major difficulty encountered in the use of these instruments resides in the realisation of photographs of the different parts of the thin section that require illustrations. The technique that has been used upto now has been inefficient and unsatisfactory. Faced with this recurrent situation, we thought of setting up a new, semi-modern, practical and very economical technique for photographing the thin section.conferenc

Neotectonic markers in the Panafrican belt formations of Cameroon: elements of interpretation and their environmental impacts

The North equatorial Panafrican Belt, whose Cameroonian formations are dated between 650 and 400 million years, and which are located in the North of the Congo Craton, is subdivided in to three major geodynamic domains: a north Cameroon domain, a central Cameroon domain and a south Cameroon domain. These major domains are generally, particularly the central domain, affected by great strikeslip faults in which the most important are the central cameroonian shear zone and the Sanaga fault. Studies that establish the order of occurrence of geological events, generally performed in these domains and particularly at Banefo area (West Cameroon) reveal markers of recent tectonics (post panafrican) that affect the granitogneissic basement...conferenc