Talc schist deposits from central Cameroon: mineralogical and physico-chemical characterization

Abstract Talc schist deposits are reported in central Cameroon region, and different alteration zones were determined depending on differences related to the texture and color of the host rock. For the purpose of determining mineralogical and physicochemical characteristics of talc schist, a total of 45 samples from the sites studied were collected and analyzed using an array of physico-chemical methods. Talc schist samples are mainly composed of variable amount of talc associated with plagioclase and clay minerals. Three groups of mineral association were determined: i) talc with small amount of chlorite and traces of kaolinite, ii) talc with high amount of chlorite, iii) variable amount of talc with plagioclase and clay minerals. The talc schist samples have homogeneous grain-sizes and are classified as silty sand or sandy silt. The occurrence of Ni and Cr in the talc schists are consistent with the composition of the talc deposits formed in relation to ultramafic rocks. The genesis of talc is due to hydrothermal fluid circulation in ultramafic rocks, attested by the occurrence of S and P.