Controlling factors of cathodeluminescence of carbonate minerals

Cathodelum inescence of carbonate minerals tends to be constrained by the Mn²⁺ and Fe²⁺ contents and Mn²⁺ /Fe²⁺ ratios.In this study,the calcite cement samples were mostly collected from the Cambrian and Ordovician carbonate rock strata in the Western Hills,Beijing.The cathodeluminescence intensities of these samples can be divided into nonluminous,weak,moderate and bright types.Correspondingly,the cathodeluminescence colours include nonluminescence,salmon,orange and bright yellow colours.The correlation of the cathodeluminescence intensities and colours based on the microprobe analysis,and the Mn²⁺ and Fe²⁺ contents and Mn²⁺ /Fe²⁺ ratios has led us to the following conclusions.The calcite cement exhibits no luminescence when there is no Mn²⁺ or only a trace amount of Fe²⁺ in the samples,and the Mn²⁺/Fe²⁺ ratios is 0.The calcite cement exhibits a weak luminescence and salmon when the Mn²⁺/Fe²⁺ ratios range between 0.05 and 0.2.The calcite cement exhibits a moderate luminescence and orange when the Mn²⁺/Fe²⁺ ratios range between 0.2 and 2.The calcite cement exhibits a bright luminescence and bright yellow when the Mn²⁺/Fe²⁺ ratios go up to more than 2.