Science and Education Publishing Journal of Geosciences and Geomatics 2373-6704 3 4 2015 08 14 Mineral Alteration and Chlorite Geothermometry in Platinum Group Element (PGE)- Bearing Meta-ultramafic Rocks from South East Cameroon 96 108 EN Ako T. A. Economic Geology Unit, Department of Geology, University of Buea, Buea South West Region, Cameroon A. Vishiti K. I. Ateh A. C. Kedia C. E. Suh JGG2015342 10.12691/jgg-3-4-2 2015 07 30 2015 08 09 2015 08 14 The meta-ultramafic rocks that are part of the Paleoproterozoic unit termed the Nyong Series in SE Cameroon were investigated in this study. The lithologic assemblage mapped is exposed on a cliff face and consists of distinguishable horizons that include least, moderately to intensely altered pyroxenite to amphibolite units. The rocks are partially to completely serpenitinized and foliated. The main mineral phases identified under the microscope include pyroxenes (clinopyroxene and orthopyroxene), olivine, hornblende, plagioclase, garnet and sulphides. The rocks depict variable alteration of the pyroxenes and other primary minerals such as olivine to actinolite, chlorite, serpentine, talc, epidote and tremolite. Electron microprobe analysis on chlorite show that the principal chlorite type ranges from talc-chlorite to penninite. Using the chlorite geothermometer it is observed that the hydrothermal alteration temperatures vary between 160-180°C. This has been overprinted by surface temperatures (20 - 40°C) during the process of weathering.