Application of cathodoluminescence microscopy to the study of carbonatite-related fluorspar ores, host rock carbonatites and beneficiation products at Okorusu, Namibia

Cathodoluminescence microscopy (CLM) is uniquely applicable to the study of carbonatite-related fluorspar ore deposits. The mineralogy of the carbonat ites, sodic and potassic fenites, marbles, quartzites and fluorite ores are readily determined and characterized. Calcite, dolomite, apatite and fluor ite were deposited dominantly tinder high-temperature conditions, and they exhibit strong cathodoluminescence (CL). At the Okorusu, Namibia, carbonati te complex and fluorspar mines, three types of carbonatites have been recog nized by field mapping and laboratory CLM. The main carbonatite intrusion i s fine grained and consists mainly of calcite. A later phase of pegmatitic carbonatite consists of calcite, magnetite, Fe-rich pyroxene, apatite and p yrochlore. Pyroxene carbonatites were recognized mainly through their study by CLM.